QGLViewer Class Reference

A versatile 3D OpenGL viewer based on QGLWidget. More...

## Signals

void | viewerInitialized ()
void | drawNeeded ()
void | drawFinished (bool automatic)
void | animateNeeded ()
void | helpRequired ()
void | axisIsDrawnChanged (bool drawn)
void | gridIsDrawnChanged (bool drawn)
void | FPSIsDisplayedChanged (bool displayed)
void | textIsEnabledChanged (bool enabled)
void | cameraIsEditedChanged (bool edited)
void | stereoChanged (bool on)
void | pointSelected (const QMouseEvent *e)
void | mouseGrabberChanged (qglviewer::MouseGrabber *mouseGrabber)

## Public Member Functions

| QGLViewer (QWidget *parent=0, const QGLWidget *shareWidget=0, Qt::WindowFlags flags=0)
| QGLViewer (QGLContext *context, QWidget *parent=0, const QGLWidget *shareWidget=0, Qt::WindowFlags flags=0)
| QGLViewer (const QGLFormat &format, QWidget *parent=0, const QGLWidget *shareWidget=0, Qt::WindowFlags flags=0)
virtual | ~QGLViewer ()

## Display of visual hints

bool | axisIsDrawn () const
bool | gridIsDrawn () const
bool | FPSIsDisplayed () const
bool | textIsEnabled () const
bool | cameraIsEdited () const
void | setAxisIsDrawn (bool draw=true)
void | setGridIsDrawn (bool draw=true)
void | setFPSIsDisplayed (bool display=true)
void | setTextIsEnabled (bool enable=true)
void | setCameraIsEdited (bool edit=true)
void | toggleAxisIsDrawn ()
void | toggleGridIsDrawn ()
void | toggleFPSIsDisplayed ()
void | toggleTextIsEnabled ()
void | toggleCameraIsEdited ()

## Viewer's colors

QColor | backgroundColor () const
QColor | foregroundColor () const
void | setBackgroundColor (const QColor &color)
void | setForegroundColor (const QColor &color)

## Scene dimensions

qreal | sceneRadius () const
qglviewer::Vec | sceneCenter () const
virtual void | setSceneRadius (qreal radius)
virtual void | setSceneCenter (const qglviewer::Vec &center)
void | setSceneBoundingBox (const qglviewer::Vec &min, const qglviewer::Vec &max)
void | showEntireScene ()

## Associated objects

qglviewer::Camera * | camera () const
qglviewer::ManipulatedFrame * | manipulatedFrame () const
void | setCamera (qglviewer::Camera *const camera)
void | setManipulatedFrame (qglviewer::ManipulatedFrame *frame)

## Mouse grabbers

qglviewer::MouseGrabber * | mouseGrabber () const
void | setMouseGrabberIsEnabled (const qglviewer::MouseGrabber *const mouseGrabber, bool enabled=true)
bool | mouseGrabberIsEnabled (const qglviewer::MouseGrabber *const mouseGrabber)
void | setMouseGrabber (qglviewer::MouseGrabber *mouseGrabber)

## State of the viewer

qreal | aspectRatio () const
qreal | currentFPS ()
bool | isFullScreen () const
bool | displaysInStereo () const
virtual QSize | sizeHint () const
void | setFullScreen (bool fullScreen=true)
void | setStereoDisplay (bool stereo=true)
void | toggleFullScreen ()
void | toggleStereoDisplay ()
void | toggleCameraMode ()

## Display methods

virtual void | startScreenCoordinatesSystem (bool upward=false) const
virtual void | stopScreenCoordinatesSystem () const
void | drawText (int x, int y, const QString &text, const QFont &fnt=QFont())
void | displayMessage (const QString &message, int delay=2000)
static void | drawArrow (qreal length=1.0, qreal radius=-1.0, int nbSubdivisions=12)
static void | drawArrow (const qglviewer::Vec &from, const qglviewer::Vec &to, qreal radius=-1.0, int nbSubdivisions=12)
static void | drawAxis (qreal length=1.0)
static void | drawGrid (qreal size=1.0, int nbSubdivisions=10)
virtual void | drawLight (GLenum light, qreal scale=1.0) const

## Useful inherited methods

int | width () const
int | height () const
virtual void | updateGL ()
void | qglColor (const QColor &color) const
void | qglClearColor (const QColor &color) const
bool | isValid () const
bool | isSharing () const
virtual void | makeCurrent ()
bool | hasMouseTracking () const
virtual void | resize (int width, int height)
virtual void | setMouseTracking (bool enable)
static QImage | convertToGLFormat (const QImage &image)
bool | autoBufferSwap () const
void | setAutoBufferSwap (bool on)

## Snapshots

const QString & | snapshotFileName () const
const QString & | snapshotFormat () const
int | snapshotCounter () const
int | snapshotQuality ()
QFont | scaledFont (const QFont &font) const
void | saveSnapshot (bool automatic=true, bool overwrite=false)
void | saveSnapshot (const QString &fileName, bool overwrite=false)
void | setSnapshotFileName (const QString &name)
void | setSnapshotFormat (const QString &format)
void | setSnapshotCounter (int counter)
void | setSnapshotQuality (int quality)
bool | openSnapshotFormatDialog ()
void | snapshotToClipboard ()

## Buffer to texture

GLuint | bufferTextureId () const
qreal | bufferTextureMaxU () const
qreal | bufferTextureMaxV () const
void | copyBufferToTexture (GLint internalFormat, GLenum format=GL_NONE)

## Animation

bool | animationIsStarted () const
int | animationPeriod () const
void | setAnimationPeriod (int period)
virtual void | startAnimation ()
virtual void | stopAnimation ()
virtual void | animate ()
void | toggleAnimation ()

## Help window

virtual QString | helpString () const
virtual QString | mouseString () const
virtual QString | keyboardString () const
virtual void | help ()
virtual void | aboutQGLViewer ()
QTabWidget * | helpWidget ()

## Drawing methods

virtual void | resizeGL (int width, int height)
virtual void | initializeGL ()
virtual void | init ()
virtual void | paintGL ()
virtual void | preDraw ()
virtual void | preDrawStereo (bool leftBuffer=true)
virtual void | draw ()
virtual void | fastDraw ()
virtual void | postDraw ()

## Mouse, keyboard and event handlers

virtual void | mousePressEvent (QMouseEvent *)
virtual void | mouseMoveEvent (QMouseEvent *)
virtual void | mouseReleaseEvent (QMouseEvent *)
virtual void | mouseDoubleClickEvent (QMouseEvent *)
virtual void | wheelEvent (QWheelEvent *)
virtual void | keyPressEvent (QKeyEvent *)
virtual void | keyReleaseEvent (QKeyEvent *)
virtual void | timerEvent (QTimerEvent *)
virtual void | closeEvent (QCloseEvent *)

## Object selection

int | selectedName () const
int | selectBufferSize () const
int | selectRegionWidth () const
int | selectRegionHeight () const
GLuint * | selectBuffer ()
virtual void | select (const QMouseEvent *event)
virtual void | select (const QPoint &point)
void | setSelectBufferSize (int size)
void | setSelectRegionWidth (int width)
void | setSelectRegionHeight (int height)
void | setSelectedName (int id)
virtual void | beginSelection (const QPoint &point)
virtual void | drawWithNames ()
virtual void | endSelection (const QPoint &point)
virtual void | postSelection (const QPoint &point)

## Keyboard customization

enum | KeyboardAction { DRAW_AXIS, DRAW_GRID, DISPLAY_FPS, ENABLE_TEXT, EXIT_VIEWER, SAVE_SCREENSHOT, CAMERA_MODE, FULL_SCREEN, STEREO, ANIMATION, HELP, EDIT_CAMERA, MOVE_CAMERA_LEFT, MOVE_CAMERA_RIGHT, MOVE_CAMERA_UP, MOVE_CAMERA_DOWN, INCREASE_FLYSPEED, DECREASE_FLYSPEED, SNAPSHOT_TO_CLIPBOARD }
unsigned int | shortcut (KeyboardAction action) const
Qt::Key | pathKey (unsigned int index) const
Qt::KeyboardModifiers | addKeyFrameKeyboardModifiers () const
Qt::KeyboardModifiers | playPathKeyboardModifiers () const
void | setShortcut (KeyboardAction action, unsigned int key)
void | setKeyDescription (unsigned int key, QString description)
void | clearShortcuts ()
virtual void | setPathKey (int key, unsigned int index=0)
virtual void | setPlayPathKeyboardModifiers (Qt::KeyboardModifiers modifiers)
virtual void | setAddKeyFrameKeyboardModifiers (Qt::KeyboardModifiers modifiers)

## Mouse customization

enum | MouseHandler { CAMERA, FRAME }
enum | ClickAction { NO_CLICK_ACTION, ZOOM_ON_PIXEL, ZOOM_TO_FIT, SELECT, RAP_FROM_PIXEL, RAP_IS_CENTER, CENTER_FRAME, CENTER_SCENE, SHOW_ENTIRE_SCENE, ALIGN_FRAME, ALIGN_CAMERA }
enum | MouseAction { NO_MOUSE_ACTION, ROTATE, ZOOM, TRANSLATE, MOVE_FORWARD, LOOK_AROUND, MOVE_BACKWARD, SCREEN_ROTATE, ROLL, DRIVE, SCREEN_TRANSLATE, ZOOM_ON_REGION }
MouseAction | mouseAction (Qt::Key key, Qt::KeyboardModifiers modifiers, Qt::MouseButton button) const
int | mouseHandler (Qt::Key key, Qt::KeyboardModifiers modifiers, Qt::MouseButton button) const
void | getMouseActionBinding (MouseHandler handler, MouseAction action, bool withConstraint, Qt::Key &key, Qt::KeyboardModifiers &modifiers, Qt::MouseButton &button) const
ClickAction | clickAction (Qt::Key key, Qt::KeyboardModifiers modifiers, Qt::MouseButton button, bool doubleClick=false, Qt::MouseButtons buttonsBefore=Qt::NoButton) const
void | getClickActionBinding (ClickAction action, Qt::Key &key, Qt::KeyboardModifiers &modifiers, Qt::MouseButton &button, bool &doubleClick, Qt::MouseButtons &buttonsBefore) const
MouseAction | wheelAction (Qt::Key key, Qt::KeyboardModifiers modifiers) const
int | wheelHandler (Qt::Key key, Qt::KeyboardModifiers modifiers) const
void | getWheelActionBinding (MouseHandler handler, MouseAction action, bool withConstraint, Qt::Key &key, Qt::KeyboardModifiers &modifiers) const
void | setMouseBinding (Qt::KeyboardModifiers modifiers, Qt::MouseButton buttons, MouseHandler handler, MouseAction action, bool withConstraint=true)
void | setMouseBinding (Qt::KeyboardModifiers modifiers, Qt::MouseButton button, ClickAction action, bool doubleClick=false, Qt::MouseButtons buttonsBefore=Qt::NoButton)
void | setWheelBinding (Qt::KeyboardModifiers modifiers, MouseHandler handler, MouseAction action, bool withConstraint=true)
void | setMouseBindingDescription (Qt::KeyboardModifiers modifiers, Qt::MouseButton button, QString description, bool doubleClick=false, Qt::MouseButtons buttonsBefore=Qt::NoButton)
void | setMouseBinding (Qt::Key key, Qt::KeyboardModifiers modifiers, Qt::MouseButton buttons, MouseHandler handler, MouseAction action, bool withConstraint=true)
void | setMouseBinding (Qt::Key key, Qt::KeyboardModifiers modifiers, Qt::MouseButton button, ClickAction action, bool doubleClick=false, Qt::MouseButtons buttonsBefore=Qt::NoButton)
void | setWheelBinding (Qt::Key key, Qt::KeyboardModifiers modifiers, MouseHandler handler, MouseAction action, bool withConstraint=true)
void | setMouseBindingDescription (Qt::Key key, Qt::KeyboardModifiers modifiers, Qt::MouseButton button, QString description, bool doubleClick=false, Qt::MouseButtons buttonsBefore=Qt::NoButton)
void | clearMouseBindings ()

## State persistence

QString | stateFileName () const
virtual QDomElement | domElement (const QString &name, QDomDocument &document) const
virtual void | initFromDOMElement (const QDomElement &element)
virtual void | saveStateToFile ()
virtual bool | restoreStateFromFile ()
void | setStateFileName (const QString &name)

## QGLViewer pool

static const QList< QGLViewer * > & | QGLViewerPool ()
static int | QGLViewerIndex (const QGLViewer *const viewer)

## Detailed Description

A versatile 3D OpenGL viewer based on QGLWidget.

It features many classical viewer functionalities, such as a camera trackball, manipulated objects, snapshot saving and much more. Its main goal is to ease the development of new 3D applications.

New users should read the introduction page to get familiar with important notions such as sceneRadius(), sceneCenter() and the world coordinate system. Try the numerous simple examples to discover the possibilities and understand how it works.

### Usage

To use a QGLViewer, derive you viewer class from the QGLViewer and overload its draw() virtual method. See the simpleViewer example for an illustration.

An other option is to connect your drawing methods to the signals emitted by the QGLViewer (Qt's callback mechanism). See the callback example for a complete implementation.

## Member Enumeration Documentation

## ClickAction

enum ClickAction

Defines the possible actions that can be binded to a mouse click using setMouseBinding(Qt::KeyboardModifiers, Qt::MouseButtons, ClickAction, bool, int).

See the mouse page for details.

Enumerator
NO_CLICK_ACTION |
ZOOM_ON_PIXEL |
ZOOM_TO_FIT |
SELECT |
RAP_FROM_PIXEL |
RAP_IS_CENTER |
CENTER_FRAME |
CENTER_SCENE |
SHOW_ENTIRE_SCENE |
ALIGN_FRAME |
ALIGN_CAMERA |

## KeyboardAction

enum KeyboardAction

Defines the different actions that can be associated with a keyboard shortcut using setShortcut().

See the keyboard page for details.

Enumerator
DRAW_AXIS |
DRAW_GRID |
DISPLAY_FPS |
ENABLE_TEXT |
EXIT_VIEWER |
SAVE_SCREENSHOT |
CAMERA_MODE |
FULL_SCREEN |
STEREO |
ANIMATION |
HELP |
EDIT_CAMERA |
MOVE_CAMERA_LEFT |
MOVE_CAMERA_RIGHT |
MOVE_CAMERA_UP |
MOVE_CAMERA_DOWN |
INCREASE_FLYSPEED |
DECREASE_FLYSPEED |
SNAPSHOT_TO_CLIPBOARD |

## MouseAction

enum MouseAction

Defines the possible actions that can be binded to a mouse action (a click, followed by a mouse displacement).

These actions may be binded to the camera() or to the manipulatedFrame() (see QGLViewer::MouseHandler) using setMouseBinding().

Enumerator
NO_MOUSE_ACTION |
ROTATE |
ZOOM |
TRANSLATE |
MOVE_FORWARD |
LOOK_AROUND |
MOVE_BACKWARD |
SCREEN_ROTATE |
ROLL |
DRIVE |
SCREEN_TRANSLATE |
ZOOM_ON_REGION |

## MouseHandler

enum MouseHandler

Defines the different mouse handlers: camera() or manipulatedFrame().

Used by setMouseBinding(), setMouseBinding(Qt::KeyboardModifiers modifiers, Qt::MouseButtons, ClickAction, bool, int) and setWheelBinding() to define which handler receives the mouse events.

Enumerator
CAMERA |
FRAME |

## Constructor & Destructor Documentation

## QGLViewer() [1/3]

QGLViewer | ( | QWidget * | parent = `0`,
|  | const QGLWidget * | shareWidget = `0`,
|  | Qt::WindowFlags | flags = `0`
| ) |  |

explicit

Constructor. See `QGLWidget` documentation for details.

All viewer parameters (display flags, scene parameters, associated objects...) are set to their default values. See the associated documentation.

If the `shareWidget` parameter points to a valid `QGLWidget`, the QGLViewer will share the OpenGL context with `shareWidget` (see isSharing()).

## QGLViewer() [2/3]

QGLViewer | ( | QGLContext * | context,
|  | QWidget * | parent = `0`,
|  | const QGLWidget * | shareWidget = `0`,
|  | Qt::WindowFlags | flags = `0`
| ) |  |

explicit

Same as QGLViewer(), but a `QGLContext` can be provided so that viewers share GL contexts, even with `QGLContext` sub-classes (use `shareWidget` otherwise).

## QGLViewer() [3/3]

QGLViewer | ( | const QGLFormat & | format,
|  | QWidget * | parent = `0`,
|  | const QGLWidget * | shareWidget = `0`,
|  | Qt::WindowFlags | flags = `0`
| ) |  |

explicit

Same as QGLViewer(), but a specific `QGLFormat` can be provided.

This is for instance needed to ask for a stencil buffer or for stereo display (as is illustrated in the stereoViewer example).

## ~QGLViewer()

~QGLViewer | ( |  | ) |

virtual

Virtual destructor.

The viewer is replaced by `NULL` in the QGLViewerPool() (in order to preserve other viewer's indexes) and allocated memory is released. The camera() is deleted and should be copied before if it is shared by an other viewer.

## Member Function Documentation

## aboutQGLViewer

void aboutQGLViewer | ( |  | ) |

virtual slot

Displays the help window "About" tab. See help() for details.

## addKeyFrameKeyboardModifiers()

Qt::KeyboardModifiers addKeyFrameKeyboardModifiers | ( |  | ) | const

Returns the keyboard modifiers that must be pressed with a pathKey() to add the current camera position to a KeyFrame path.

It can be `Qt::NoModifier`, `Qt::ControlModifier`, `Qt::ShiftModifier`, `Qt::AltModifier`, `Qt::MetaModifier` or a combination of these (using the bitwise '|' operator).

Default value is Qt::AltModifier. Defined using setAddKeyFrameKeyboardModifiers().

See also playPathKeyboardModifiers().

## animate

virtual void animate | ( |  | ) |

virtual slot

Scene animation method.

    When animationIsStarted(), this method is in charge of the scene update before each draw().
    Overload it to define how your scene evolves over time. The time should either be regularly
    incremented in this method (frame-rate independent animation) or computed from actual time (for
    instance using QTime::elapsed()) for real-time animations.

                Note that KeyFrameInterpolator (which regularly updates a Frame) does not use this method
                to animate a Frame, but rather rely on a QTimer signal-slot mechanism.

    See the <a href="../examples/animation.html">animation example</a> for an illustration.

## animateNeeded

void animateNeeded | ( |  | ) |

signal

Signal emitted by the default animate() method.

Connect this signal to your scene animation method or overload animate().

## animationIsStarted()

bool animationIsStarted | ( |  | ) | const

Return `true` when the animation loop is started.

During animation, an infinite loop calls animate() and draw() and then waits for animationPeriod() milliseconds before calling animate() and draw() again. And again.

Use startAnimation(), stopAnimation() or toggleAnimation() to change this value.

See the animation example for illustration.

## animationPeriod()

int animationPeriod | ( |  | ) | const

The animation loop period, in milliseconds.

When animationIsStarted(), this is delay waited after draw() to call animate() and draw() again. Default value is 40 milliseconds (25 Hz).

This value will define the currentFPS() when animationIsStarted() (provided that your animate() and draw() methods are fast enough).

If you want to know the maximum possible frame rate of your machine on a given scene, setAnimationPeriod() to `0`, and startAnimation() (keyboard shortcut is `Enter`). The display will then be updated as often as possible, and the frame rate will be meaningful.

Note
  This value is taken into account only the next time you call startAnimation(). If animationIsStarted(), you should stopAnimation() first.

## aspectRatio()

qreal aspectRatio | ( |  | ) | const

Returns the aspect ratio of the viewer's widget (width() / height()).

## autoBufferSwap()

bool autoBufferSwap | ( |  | ) | const

protected

Returns `true` when buffers are automatically swapped (default). See details in the QGLWidget documentation.

## axisIsDrawn()

bool axisIsDrawn | ( |  | ) | const

Returns `true` if the world axis is drawn by the viewer.

Set by setAxisIsDrawn() or toggleAxisIsDrawn(). Default value is `false`.

## axisIsDrawnChanged

void axisIsDrawnChanged | ( | bool | drawn | ) |

signal

This signal is emitted whenever axisIsDrawn() changes value.

## backgroundColor()

QColor backgroundColor | ( |  | ) | const

Returns the background color of the viewer.

This method is provided for convenience since the background color is an OpenGL state variable set with `glClearColor()`. However, this internal representation has the advantage that it is saved (resp. restored) with saveStateToFile() (resp. restoreStateFromFile()).

Use setBackgroundColor() to define and activate a background color.

Attention
  Each QColor component is an integer ranging from 0 to 255. This differs from the qreal values used by `glClearColor()` which are in the 0.0-1.0 range. Default value is (51, 51, 51) (dark gray). You may have to change foregroundColor() accordingly.
  This method does not return the current OpenGL clear color as `glGet()` does. Instead, it returns the QGLViewer internal variable. If you directly use `glClearColor()` or `qglClearColor()` instead of setBackgroundColor(), the two results will differ.

## beginSelection()

void beginSelection | ( | const QPoint & | point | ) |

protected virtual

This method should prepare the selection. It is called by select() before drawWithNames().

The default implementation uses the `GL_SELECT` mode to perform a selection. It uses selectBuffer() and selectBufferSize() to define a `glSelectBuffer()`. The `GL_PROJECTION` is then set using `gluPickMatrix()`, with a window selection size defined by selectRegionWidth() and selectRegionHeight(). Finally, the `GL_MODELVIEW` matrix is set to the world coordinate system using qglviewer::Camera::loadModelViewMatrix(). See the gluPickMatrix() documentation for details.

You should not need to redefine this method (if you use the `GL_SELECT` mode to perform your selection), since this code is fairly classical and can be tuned. You are more likely to overload endSelection() if you want to use a more complex select buffer structure.

## bufferTextureId()

GLuint bufferTextureId | ( |  | ) | const

Returns the texture id of the texture created by copyBufferToTexture().

Use glBindTexture() to use this texture. Note that this is already done by copyBufferToTexture().

Returns `0` is copyBufferToTexture() was never called or if the texure was deleted using glDeleteTextures() since then.

## bufferTextureMaxU()

qreal bufferTextureMaxU | ( |  | ) | const

Returns the texture coordinate corresponding to the u extremum of the bufferTexture.

The bufferTexture is created by copyBufferToTexture(). The texture size has powers of two dimensions and the buffer image hence only fills a part of it. This value corresponds to the u coordinate of the extremum right side of the buffer image.

Use (0,0) to (bufferTextureMaxU(), bufferTextureMaxV()) texture coordinates to map the entire texture on a quad.

## bufferTextureMaxV()

qreal bufferTextureMaxV | ( |  | ) | const

Same as bufferTextureMaxU(), but for the v texture coordinate.

## camera()

qglviewer::Camera* camera | ( |  | ) | const

Returns the associated qglviewer::Camera, never `NULL`.

## cameraIsEdited()

bool cameraIsEdited | ( |  | ) | const

Returns `true` if the camera() is being edited in the viewer.

Set by setCameraIsEdited() or toggleCameraIsEdited(). Default value is `false`.

The current implementation is limited: the defined camera() paths (see qglviewer::Camera::keyFrameInterpolator()) are simply displayed using qglviewer::Camera::drawAllPaths(). Actual camera and path edition will be implemented in the future.

## cameraIsEditedChanged

void cameraIsEditedChanged | ( | bool | edited | ) |

signal

This signal is emitted whenever cameraIsEdited() changes value..

## clearMouseBindings

void clearMouseBindings | ( |  | ) |

slot

Clears all the default mouse bindings.

After this call, you will have to use setMouseBinding() and setWheelBinding() to restore the mouse bindings you are interested in.

## clearShortcuts

void clearShortcuts | ( |  | ) |

slot

Clears all the default keyboard shortcuts.

After this call, you will have to use setShortcut() to define your own keyboard shortcuts.

## clickAction()

QGLViewer::ClickAction clickAction | ( | Qt::Key | key,
|  | Qt::KeyboardModifiers | modifiers,
|  | Qt::MouseButton | button,
|  | bool | doubleClick = `false`,
|  | Qt::MouseButtons | buttonsBefore = `Qt::NoButton`
| ) |  | const

Same as mouseAction(), but for the ClickAction set using setMouseBinding().

Returns NO_CLICK_ACTION if no click action is associated with this keyboard and mouse buttons combination.

## closeEvent()

void closeEvent | ( | QCloseEvent * | e | ) |

protected virtual

Overloading of the `QWidget` method.

Saves the viewer state using saveStateToFile() and then calls QGLWidget::closeEvent().

## convertToGLFormat()

static QImage convertToGLFormat | ( | const QImage & | image | ) |

static

Converts `image` into the unnamed format expected by OpenGL methods such as glTexImage2D(). See QGLWidget documentation.

## copyBufferToTexture

void copyBufferToTexture | ( | GLint | internalFormat,
|  | GLenum | format = `GL_NONE`
| ) |  |

slot

Makes a copy of the current buffer into a texture.

Creates a texture (when needed) and uses glCopyTexSubImage2D() to directly copy the buffer in it.

Use `internalFormat` and `format` to define the texture format and hence which and how components of the buffer are copied into the texture. See the glTexImage2D() documentation for details.

When `format` is c GL_NONE (default), its value is set to `internalFormat`, which fits most cases. Typical `internalFormat` (and `format`) values are `GL_DEPTH_COMPONENT` and `GL_RGBA`. Use `GL_LUMINANCE` as the `internalFormat` and `GL_RED`, `GL_GREEN` or `GL_BLUE` as `format` to capture a single color component as a luminance (grey scaled) value. Note that `GL_STENCIL` is not supported as a format.

The texture has dimensions which are powers of two. It is as small as possible while always being larger or equal to the current size of the widget. The buffer image hence does not entirely fill the texture: it is stuck to the lower left corner (corresponding to the (0,0) texture coordinates). Use bufferTextureMaxU() and bufferTextureMaxV() to get the upper right corner maximum u and v texture coordinates. Use bufferTextureId() to retrieve the id of the created texture.

Here is how to display a grey-level image of the z-buffer:

copyBufferToTexture(GL_DEPTH_COMPONENT);
glMatrixMode(GL_TEXTURE);
glLoadIdentity();
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
glEnable(GL_TEXTURE_2D);
startScreenCoordinatesSystem(true);
glBegin(GL_QUADS);
glTexCoord2f(0.0, 0.0); glVertex2i(0, 0);
glTexCoord2f(bufferTextureMaxU(), 0.0); glVertex2i(width(), 0);
glTexCoord2f(bufferTextureMaxU(), bufferTextureMaxV()); glVertex2i(width(), height());
glTexCoord2f(0.0, bufferTextureMaxV()); glVertex2i(0, height());
glEnd();
stopScreenCoordinatesSystem();
glDisable(GL_TEXTURE_2D);

Use glReadBuffer() to select which buffer is copied into the texture. See also `glPixelTransfer()`, `glPixelZoom()` and `glCopyPixel()` for pixel color transformations during copy.

Call makeCurrent() before this method to make the OpenGL context active if needed.

Note
  The `GL_DEPTH_COMPONENT` format may not be supported by all hardware. It may sometimes be emulated in software, resulting in poor performances.
  The bufferTextureId() texture is binded at the end of this method.

## currentFPS()

qreal currentFPS | ( |  | ) |

Returns the current averaged viewer frame rate.

This value is computed and averaged over 20 successive frames. It only changes every 20 draw() (previously computed value is otherwise returned).

This method is useful for true real-time applications that may adapt their computational load accordingly in order to maintain a given frequency.

This value is meaningful only when draw() is regularly called, either using a `QTimer`, when animationIsStarted() or when the camera is manipulated with the mouse.

## displayMessage()

void displayMessage | ( | const QString & | message,
|  | int | delay = `2000`
| ) |  |

Briefly displays a message in the lower left corner of the widget. Convenient to provide feedback to the user.

`message` is displayed during `delay` milliseconds (default is 2 seconds) using drawText().

This method should not be called in draw(). If you want to display a text in each draw(), use drawText() instead.

If this method is called when a message is already displayed, the new message replaces the old one. Use setTextIsEnabled() (default shortcut is '?') to enable or disable text (and hence messages) display.

## displaysInStereo()

bool displaysInStereo | ( |  | ) | const

Returns `true` if the viewer displays in stereo.

The QGLViewer object must be created with a stereo format to handle stereovision:

QGLFormat format;
format.setStereoDisplay( TRUE );
QGLViewer viewer(format);

The hardware needs to support stereo display. Try the stereoViewer example to check.

Set by setStereoDisplay() or toggleStereoDisplay(). Default value is `false`.

Stereo is performed using the Parallel axis asymmetric frustum perspective projection method. See Camera::loadProjectionMatrixStereo() and Camera::loadModelViewMatrixStereo().

The stereo parameters are defined by the camera(). See qglviewer::Camera::setIODistance(), qglviewer::Camera::setPhysicalScreenWidth() and qglviewer::Camera::setFocusDistance().

## domElement()

QDomElement domElement | ( | const QString & | name,
|  | QDomDocument & | document
| ) |  | const

virtual

Returns an XML `QDomElement` that represents the QGLViewer.

Used by saveStateToFile(). restoreStateFromFile() uses initFromDOMElement() to restore the QGLViewer state from the resulting `QDomElement`.

`name` is the name of the QDomElement tag. `doc` is the `QDomDocument` factory used to create QDomElement.

The created QDomElement contains state values (axisIsDrawn(), FPSIsDisplayed(), isFullScreen()...), viewer geometry, as well as camera() (see qglviewer::Camera::domElement()) and manipulatedFrame() (if defined, see qglviewer::ManipulatedFrame::domElement()) states.

Overload this method to add your own attributes to the state file:

QDomElement Viewer::domElement(const QString& name, QDomDocument& document) const
{
// Creates a custom node for a light
QDomElement de = document.createElement("Light");
de.setAttribute("state", (lightIsOn()?"on":"off"));
// Note the include of the ManipulatedFrame domElement method.
de.appendChild(lightManipulatedFrame()->domElement("LightFrame", document));
// Get default state domElement and append custom node
QDomElement res = QGLViewer::domElement(name, document);
res.appendChild(de);
return res;
}

See initFromDOMElement() for the associated restoration code.

Attention
  For the manipulatedFrame(), qglviewer::Frame::constraint() and qglviewer::Frame::referenceFrame() are not saved. See qglviewer::Frame::domElement().

## draw()

virtual void draw | ( |  | ) |

protected virtual

The core method of the viewer, that draws the scene.

If you build a class that inherits from QGLViewer, this is the method you want to overload. See the simpleViewer example for an illustration.

The camera modelView matrix set in preDraw() converts from the world to the camera coordinate systems. Vertices given in draw() can then be considered as being given in the world coordinate system. The camera is moved in this world using the mouse. This representation is much more intuitive than the default camera-centric OpenGL standard.

Attention
  The `GL_PROJECTION` matrix should not be modified by this method, to correctly display visual hints (axis, grid, FPS...) in postDraw(). Use push/pop or call camera()->loadProjectionMatrix() at the end of draw() if you need to change the projection matrix (unlikely). On the other hand, the `GL_MODELVIEW` matrix can be modified and left in a arbitrary state.

## drawArrow() [1/2]

void drawArrow | ( | qreal | length = `1.0`,
|  | qreal | radius = `-1.0`,
|  | int | nbSubdivisions = `12`
| ) |  |

static

Draws a 3D arrow along the positive Z axis.

`length`, `radius` and `nbSubdivisions` define its geometry. If `radius` is negative (default), it is set to 0.05 * `length`.

Use drawArrow(const Vec& from, const Vec& to, qreal radius, int nbSubdivisions) or change the `ModelView` matrix to place the arrow in 3D.

Uses current color and does not modify the OpenGL state.

## drawArrow() [2/2]

void drawArrow | ( | const qglviewer::Vec & | from,
|  | const qglviewer::Vec & | to,
|  | qreal | radius = `-1.0`,
|  | int | nbSubdivisions = `12`
| ) |  |

static

Draws a 3D arrow between the 3D point `from` and the 3D point `to`, both defined in the current ModelView coordinates system.

See drawArrow(qreal length, qreal radius, int nbSubdivisions) for details.

## drawAxis()

void drawAxis | ( | qreal | length = `1.0` | ) |

static

Draws an XYZ axis, with a given size (default is 1.0).

The axis position and orientation matches the current modelView matrix state: three arrows (red, green and blue) of length `length` are drawn along the positive X, Y and Z directions.

Use the following code to display the current position and orientation of a qglviewer::Frame:

glPushMatrix();
glMultMatrixd(frame.matrix());
QGLViewer::drawAxis(sceneRadius() / 5.0); // Or any scale
glPopMatrix();

The current color and line width are used to draw the X, Y and Z characters at the extremities of the three arrows. The OpenGL state is not modified by this method.

axisIsDrawn() uses this method to draw a representation of the world coordinate system. See also QGLViewer::drawArrow() and QGLViewer::drawGrid().

## drawFinished

void drawFinished | ( | bool | automatic | ) |

signal

Signal emitted at the end of the QGLViewer::paintGL() method, when frame is drawn.

Can be used to notify an image grabbing process that the image is ready. A typical example is to connect this signal to the saveSnapshot() method, so that a (numbered) snapshot is generated after each new display, in order to create a movie:

connect(viewer, SIGNAL(drawFinished(bool)), SLOT(saveSnapshot(bool)));

The `automatic` bool variable is always `true` and has been added so that the signal can be connected to saveSnapshot() with an `automatic` value set to `true`.

## drawGrid()

void drawGrid | ( | qreal | size = `1.0`,
|  | int | nbSubdivisions = `10`
| ) |  |

static

Draws a grid in the XY plane, centered on (0,0,0) (defined in the current coordinate system).

`size` (OpenGL units) and `nbSubdivisions` define its geometry. Set the `GL_MODELVIEW` matrix to place and orientate the grid in 3D space (see the drawAxis() documentation).

The OpenGL state is not modified by this method.

## drawLight()

void drawLight | ( | GLenum | light,
|  | qreal | scale = `1.0`
| ) |  | const

protected virtual

Draws a representation of `light`.

Called in draw(), this method is useful to debug or display your light setup. Light drawing depends on the type of light (point, spot, directional).

The method retrieves the light setup using `glGetLightfv`. Position and define your lights before calling this method.

Light is drawn using its diffuse color. Disabled lights are not displayed.

Drawing size is proportional to sceneRadius(). Use `scale` to rescale it.

See the drawLight example for an illustration.

Attention
  You need to enable `GL_COLOR_MATERIAL` before calling this method. `glColor` is set to the light diffuse color.

## drawNeeded

void drawNeeded | ( |  | ) |

signal

Signal emitted by the default draw() method.

Connect this signal to your main drawing method or overload draw(). See the callback example for an illustration.

## drawText()

void drawText | ( | int | x,
|  | int | y,
|  | const QString & | text,
|  | const QFont & | fnt = `QFont()`
| ) |  |

Draws `text` at position `x`, `y` (expressed in screen coordinates pixels, origin in the upper left corner of the widget).

The default QApplication::font() is used to render the text when no `fnt` is specified. Use QApplication::setFont() to define this default font.

You should disable `GL_LIGHTING` and `GL_DEPTH_TEST` before this method so that colors are properly rendered.

This method can be used in conjunction with the qglviewer::Camera::projectedCoordinatesOf() method to display a text attached to an object. In your draw() method use:

qglviewer::Vec screenPos = camera()->projectedCoordinatesOf(myFrame.position());
drawText((int)screenPos[0], (int)screenPos[1], "My Object");

See the screenCoordSystem example for an illustration.

Text is displayed only when textIsEnabled() (default). This mechanism allows the user to conveniently remove all the displayed text with a single keyboard shortcut.

See also displayMessage() to drawText() for only a short amount of time.

Use QGLWidget::renderText(x,y,z, text) instead if you want to draw a text located at a specific 3D position instead of 2D screen coordinates (fixed size text, facing the camera).

The `GL_MODELVIEW` and `GL_PROJECTION` matrices are not modified by this method.

Attention
  This method uses display lists to render the characters, with an index that starts at 2000 by default (see the QGLWidget::renderText() documentation). If you use more than 2000 Display Lists, they may overlap with these. Directly use QGLWidget::renderText() in that case, with a higher `listBase` parameter (or overload `fontDisplayListBase`).

## drawWithNames()

virtual void drawWithNames | ( |  | ) |

protected virtual

This method is called by select() and should draw selectable entities.

Default implementation is empty. Overload and draw the different elements of your scene you want to be able to select. The default select() implementation relies on the `GL_SELECT`, and requires that each selectable element is drawn within a `glPushName()` - `glPopName()` block. A typical usage would be (see the select example):

void Viewer::drawWithNames() {
for (int i=0; i<nbObjects; ++i) {
glPushName(i);
object(i)->draw();
glPopName();
}
}

        The resulting selected name is computed by endSelection(), which setSelectedName() to the integer
        id pushed by this method (a value of -1 means no selection). Use selectedName() to update your
        selection, probably in the postSelection() method.

        \attention If your selected objects are points, do not use \c glBegin(GL_POINTS); and \c glVertex3fv()
        in the above \c draw() method (not compatible with raster mode): use \c glRasterPos3fv() instead.

## endSelection()

void endSelection | ( | const QPoint & | point | ) |

protected virtual

This method is called by select() after scene elements were drawn by drawWithNames(). It should analyze the selection result to determine which object is actually selected.

The default implementation relies on `GL_SELECT` mode (see beginSelection()). It assumes that names were pushed and popped in drawWithNames(), and analyzes the selectBuffer() to find the name that corresponds to the closer (z min) object. It then setSelectedName() to this value, or to -1 if the selectBuffer() is empty (no object drawn in selection region). Use selectedName() (probably in the postSelection() method) to retrieve this value and update your data structure accordingly.

This default implementation, although sufficient for many cases is however limited and you may have to overload this method. This will be the case if drawWithNames() uses several push levels in the name heap. A more precise depth selection, for instance privileging points over edges and triangles to avoid z precision problems, will also require an overloading. A typical implementation will look like:

glFlush();
// Get the number of objects that were seen through the pick matrix frustum.
// Resets GL_RENDER mode.
GLint nbHits = glRenderMode(GL_RENDER);
if (nbHits <= 0)
setSelectedName(-1);
else
{
// Interpret results: each object created values in the selectBuffer().
// See the glSelectBuffer() man page for details on the buffer structure.
// The following code depends on your selectBuffer() structure.
for (int i=0; i<nbHits; ++i)
if ((selectBuffer())[i*4+1] < zMin)
setSelectedName((selectBuffer())[i*4+3])
}

See the multiSelect example for a multi-object selection implementation of this method.

## fastDraw()

void fastDraw | ( |  | ) |

protected virtual

Draws a simplified version of the scene to guarantee interactive camera displacements.

This method is called instead of draw() when the qglviewer::Camera::frame() is qglviewer::ManipulatedCameraFrame::isManipulated(). Default implementation simply calls draw().

Overload this method if your scene is too complex to allow for interactive camera manipulation. See the fastDraw example for an illustration.

## foregroundColor()

QColor foregroundColor | ( |  | ) | const

Returns the foreground color used by the viewer.

This color is used when FPSIsDisplayed(), gridIsDrawn(), to display the camera paths when the cameraIsEdited().

Attention
  Each QColor component is an integer in the range 0-255. This differs from the qreal values used by `glColor3f()` which are in the range 0-1. Default value is (180, 180, 180) (light gray).

Use `qglColor(foregroundColor())` to set the current OpenGL color to the foregroundColor().

See also backgroundColor().

## FPSIsDisplayed()

bool FPSIsDisplayed | ( |  | ) | const

Returns `true` if the viewer displays the current frame rate (Frames Per Second).

Use QApplication::setFont() to define the display font (see drawText()).

Set by setFPSIsDisplayed() or toggleFPSIsDisplayed(). Use currentFPS() to get the current FPS. Default value is `false`.

## FPSIsDisplayedChanged

void FPSIsDisplayedChanged | ( | bool | displayed | ) |

signal

This signal is emitted whenever FPSIsDisplayed() changes value.

## getClickActionBinding()

void getClickActionBinding | ( | ClickAction | action,
|  | Qt::Key & | key,
|  | Qt::KeyboardModifiers & | modifiers,
|  | Qt::MouseButton & | button,
|  | bool & | doubleClick,
|  | Qt::MouseButtons & | buttonsBefore
| ) |  | const

Returns the mouse and keyboard state that triggers `action`.

If such a binding exists, results are stored in the `key`, `modifiers`, `button`, `doubleClick` and `buttonsBefore` parameters. If the ClickAction `action` is not bound, `button` is set to `Qt::NoButton`. If several mouse buttons trigger in the ClickAction, one of them is returned.

See also setMouseBinding(), getMouseActionBinding() and getWheelActionBinding().

## getMouseActionBinding()

void getMouseActionBinding | ( | MouseHandler | handler,
|  | MouseAction | action,
|  | bool | withConstraint,
|  | Qt::Key & | key,
|  | Qt::KeyboardModifiers & | modifiers,
|  | Qt::MouseButton & | button
| ) |  | const

Returns the mouse and keyboard state that triggers `action` on `handler` `withConstraint`.

If such a binding exists, results are stored in the `key`, `modifiers` and `button` parameters. If the MouseAction `action` is not bound, `button` is set to `Qt::NoButton`. If several mouse and keyboard states trigger the MouseAction, one of them is returned.

See also setMouseBinding(), getClickActionBinding() and getWheelActionBinding().

## getWheelActionBinding()

void getWheelActionBinding | ( | MouseHandler | handler,
|  | MouseAction | action,
|  | bool | withConstraint,
|  | Qt::Key & | key,
|  | Qt::KeyboardModifiers & | modifiers
| ) |  | const

Returns the keyboard state that triggers `action` on `handler` `withConstraint` using the mouse wheel.

If such a binding exists, results are stored in the `key` and `modifiers` parameters. If the MouseAction `action` is not bound, `key` is set to the illegal -1 value. If several keyboard states trigger the MouseAction, one of them is returned.

See also setMouseBinding(), getClickActionBinding() and getMouseActionBinding().

## gridIsDrawn()

bool gridIsDrawn | ( |  | ) | const

Returns `true` if a XY grid is drawn by the viewer.

Set by setGridIsDrawn() or toggleGridIsDrawn(). Default value is `false`.

## gridIsDrawnChanged

void gridIsDrawnChanged | ( | bool | drawn | ) |

signal

This signal is emitted whenever gridIsDrawn() changes value.

## hasMouseTracking()

bool hasMouseTracking | ( |  | ) | const

Returns `true` if mouseMoveEvent() is called even when no mouse button is pressed.

You need to setMouseTracking() to `true` in order to use MouseGrabber (see mouseGrabber()). See details in the QWidget documentation.

## height()

int height | ( |  | ) | const

Returns viewer's widget height (in pixels). See QGLWidget documentation.

## help

void help | ( |  | ) |

virtual slot

Opens a modal help window that includes four tabs, respectively filled with helpString(), keyboardString(), mouseString() and about libQGLViewer.

Rich html-like text can be used (see the QStyleSheet documentation). This method is called when the user presses the HELP key (default is 'H').

You can use helpWidget() to access to the help widget (to add/remove tabs, change layout...).

The helpRequired() signal is emitted.

## helpRequired

void helpRequired | ( |  | ) |

signal

Signal emitted by the default QGLViewer::help() method.

Connect this signal to your own help method or overload help().

## helpString()

virtual QString helpString | ( |  | ) | const

virtual

Returns the QString displayed in the help() window main tab.

Overload this method to define your own help string, which should shortly describe your application and explain how it works. Rich-text (HTML) tags can be used (see QStyleSheet() documentation for available tags):

QString myViewer::helpString() const
{
QString text("<h2>M y V i e w e r</h2>");
text += "Displays a <b>Scene</b> using OpenGL. Move the camera using the mouse.";
return text;
}

See also mouseString() and keyboardString().

## helpWidget()

QTabWidget* helpWidget | ( |  | ) |

protected

Returns a pointer to the help widget.

Use this only if you want to directly modify the help widget. Otherwise use helpString(), setKeyDescription() and setMouseBindingDescription() to customize the text displayed in the help window tabs.

## init()

virtual void init | ( |  | ) |

protected virtual

Initializes the viewer OpenGL context.

This method is called before the first drawing and should be overloaded to initialize some of the OpenGL flags. The default implementation is empty. See initializeGL().

Typical usage include camera() initialization (showEntireScene()), previous viewer state restoration (restoreStateFromFile()), OpenGL state modification and display list creation.

Note that initializeGL() modifies the standard OpenGL context. These values can be restored back in this method.

Attention
  You should not call updateGL() (or any method that calls it) in this method, as it will result in an infinite loop. The different QGLViewer set methods (setAxisIsDrawn(), setFPSIsDisplayed()...) are protected against this problem and can safely be called.

Note
  All the OpenGL specific initializations must be done in this method: the OpenGL context is not yet available in your viewer constructor.

## initFromDOMElement

void initFromDOMElement | ( | const QDomElement & | element | ) |

virtual slot

Restores the QGLViewer state from a `QDomElement` created by domElement().

Used by restoreStateFromFile() to restore the QGLViewer state from a file.

Overload this method to retrieve custom attributes from the QGLViewer state file. This code corresponds to the one given in the domElement() documentation:

void Viewer::initFromDOMElement(const QDomElement& element)
{
// Restore standard state
QGLViewer::initFromDOMElement(element);
QDomElement child=element.firstChild().toElement();
while (!child.isNull())
{
if (child.tagName() == "Light")
{
if (child.hasAttribute("state"))
setLightOn(child.attribute("state").toLower() == "on");
// Assumes there is only one child. Otherwise you need to parse child's children recursively.
QDomElement lf = child.firstChild().toElement();
if (!lf.isNull() && lf.tagName() == "LightFrame")
lightManipulatedFrame()->initFromDomElement(lf);
}
child = child.nextSibling().toElement();
}
}

See also qglviewer::Camera::initFromDOMElement(), qglviewer::ManipulatedFrame::initFromDOMElement().

Note
  The manipulatedFrame() pointer is not modified by this method. If defined, its state is simply set from the `element` values.

## initializeGL()

void initializeGL | ( |  | ) |

protected virtual

Initializes the QGLViewer OpenGL context and then calls user-defined init().

This method is automatically called once, before the first call to paintGL().

Overload init() instead of this method to modify viewer specific OpenGL state or to create display lists.

To make beginners' life easier and to simplify the examples, this method slightly modifies the standard OpenGL state:

glEnable(GL_LIGHT0);
glEnable(GL_LIGHTING);
glEnable(GL_DEPTH_TEST);
glEnable(GL_COLOR_MATERIAL);

If you port an existing application to QGLViewer and your display changes, you probably want to disable these flags in init() to get back to a standard OpenGL state.

## isFullScreen()

bool isFullScreen | ( |  | ) | const

Returns `true` if the viewer is in fullScreen mode.

Default value is `false`. Set by setFullScreen() or toggleFullScreen().

Note that if the QGLViewer is embedded in an other QWidget, it returns `true` when the top level widget is in full screen mode.

## isSharing()

bool isSharing | ( |  | ) | const

Returns `true` if display list sharing with another QGLWidget was requested in the constructor. See QGLWidget documentation.

## isValid()

bool isValid | ( |  | ) | const

Returns `true` if the widget has a valid GL rendering context. See QGLWidget documentation.

## keyboardString()

QString keyboardString | ( |  | ) | const

virtual

Returns a QString that describes the application keyboard shortcut bindings, and that will be displayed in the help() window `Keyboard` tab.

Default value is a table that describes the custom shortcuts defined using setKeyDescription() as well as the standard QGLViewer::KeyboardAction shortcuts (defined using setShortcut()). See the keyboard page for details on key customization.

See also helpString() and mouseString().

## keyPressEvent()

void keyPressEvent | ( | QKeyEvent * | e | ) |

protected virtual

Overloading of the `QWidget` method.

Default keyboard shortcuts are defined using setShortcut(). Overload this method to implement a specific keyboard binding. Call the original method if you do not catch the event to preserve the viewer default key bindings:

void Viewer::keyPressEvent(QKeyEvent *e)
{
// Defines the Alt+R shortcut.
if ((e->key() == Qt::Key_R) && (e->modifiers() == Qt::AltModifier))
{
myResetFunction();
update(); // Refresh display
}
else
QGLViewer::keyPressEvent(e);
}
// With Qt 2 or 3, you would retrieve modifiers keys using :
// const Qt::ButtonState modifiers = (Qt::ButtonState)(e->state() & Qt::KeyButtonMask);

When you define a new keyboard shortcut, use setKeyDescription() to provide a short description which is displayed in the help() window Keyboard tab. See the keyboardAndMouse example for an illustration.

See also QGLWidget::keyReleaseEvent().

## keyReleaseEvent()

void keyReleaseEvent | ( | QKeyEvent * | e | ) |

protected virtual

## makeCurrent()

virtual void makeCurrent | ( |  | ) |

virtual

Makes this widget's rendering context the current OpenGL rendering context. Useful with several viewers. See QGLWidget documentation.

## manipulatedFrame()

qglviewer::ManipulatedFrame* manipulatedFrame | ( |  | ) | const

Returns the viewer's qglviewer::ManipulatedFrame.

This qglviewer::ManipulatedFrame can be moved with the mouse when the associated mouse bindings are used (default is when pressing the `Control` key with any mouse button). Use setMouseBinding() to define new bindings.

See the manipulatedFrame example for a complete implementation.

Default value is `NULL`, meaning that no qglviewer::ManipulatedFrame is set.

## mouseAction()

QGLViewer::MouseAction mouseAction | ( | Qt::Key | key,
|  | Qt::KeyboardModifiers | modifiers,
|  | Qt::MouseButton | button
| ) |  | const

This method is deprecated since version 2.5.0

Use mouseAction(Qt::Key, Qt::KeyboardModifiers, Qt::MouseButtons) instead.

Returns the MouseAction the will be triggered when the mouse `button` is pressed, while the keyboard `modifiers` and `key` are pressed.

Returns NO_MOUSE_ACTION if no action is associated with this combination. Use 0 for `key` to indicate that no regular key needs to be pressed.

For instance, to know which motion corresponds to Alt+LeftButton, do:

QGLViewer::MouseAction ma = mouseAction(0, Qt::AltModifier, Qt::LeftButton);
if (ma != NO_MOUSE_ACTION) ...

Use mouseHandler() to know which object (CAMERA or FRAME) will execute this action.

## mouseDoubleClickEvent()

void mouseDoubleClickEvent | ( | QMouseEvent * | e | ) |

protected virtual

Overloading of the `QWidget` method.

The behavior of the mouse double click depends on the mouse binding. See setMouseBinding() and the mouse page.

## mouseGrabber()

qglviewer::MouseGrabber* mouseGrabber | ( |  | ) | const

Returns the current qglviewer::MouseGrabber, or `NULL` if no qglviewer::MouseGrabber currently grabs mouse events.

When qglviewer::MouseGrabber::grabsMouse(), the different mouse events are sent to the mouseGrabber() instead of their usual targets (camera() or manipulatedFrame()).

See the qglviewer::MouseGrabber documentation for details on MouseGrabber's mode of operation.

In order to use MouseGrabbers, you need to enable mouse tracking (so that mouseMoveEvent() is called even when no mouse button is pressed). Add this line in init() or in your viewer constructor:

setMouseTracking(true);

Note that mouse tracking is disabled by default. Use QWidget::hasMouseTracking() to retrieve current state.

## mouseGrabberChanged

void mouseGrabberChanged | ( | qglviewer::MouseGrabber * | mouseGrabber | ) |

signal

Signal emitted by setMouseGrabber() when the mouseGrabber() is changed.

`mouseGrabber` is a pointer to the new MouseGrabber. Note that this signal is emitted with a `NULL` parameter each time a MouseGrabber stops grabbing mouse.

## mouseGrabberIsEnabled()

bool mouseGrabberIsEnabled | ( | const qglviewer::MouseGrabber *const | mouseGrabber | ) |

Returns `true` if `mouseGrabber` is enabled.

Default value is `true` for all MouseGrabbers. When set to `false` using setMouseGrabberIsEnabled(), the specified `mouseGrabber` will never become the mouseGrabber() of this QGLViewer. This is useful when you use several viewers: some MouseGrabbers may only have a meaning for some specific viewers and should not be selectable in others.

You can also use qglviewer::MouseGrabber::removeFromMouseGrabberPool() to completely disable a MouseGrabber in all the QGLViewers.

## mouseHandler()

int mouseHandler | ( | Qt::Key | key,
|  | Qt::KeyboardModifiers | modifiers,
|  | Qt::MouseButton | button
| ) |  | const

This method is deprecated since version 2.5.0

Use mouseHanler(Qt::Key, Qt::KeyboardModifiers, Qt::MouseButtons) instead.

Returns the MouseHandler which will be activated when the mouse `button` is pressed, while the `modifiers` and `key` are pressed.

If no action is associated with this combination, returns `-1`. Use 0 for `key` and Qt::NoModifier for `modifiers` to represent the lack of a key press.

For instance, to know which handler receives the Alt+LeftButton, do:

int mh = mouseHandler(0, Qt::AltModifier, Qt::LeftButton);
if (mh == CAMERA) ...

Use mouseAction() to know which action (see the MouseAction enum) will be performed on this handler.

## mouseMoveEvent()

void mouseMoveEvent | ( | QMouseEvent * | e | ) |

protected virtual

Overloading of the `QWidget` method.

Mouse move event is sent to the mouseGrabber() (if any) or to the camera() or the manipulatedFrame(), depending on mouse bindings (see setMouseBinding()).

If you want to define your own mouse behavior, do something like this:

void Viewer::mousePressEvent(QMouseEvent* e)
{
if ((e->button() == myButton) && (e->modifiers() == myModifiers))
myMouseBehavior = true;
else
QGLViewer::mousePressEvent(e);
}
void Viewer::mouseMoveEvent(QMouseEvent *e)
{
if (myMouseBehavior)
// Use e->x() and e->y() as you want...
else
QGLViewer::mouseMoveEvent(e);
}
void Viewer::mouseReleaseEvent(QMouseEvent* e)
{
if (myMouseBehavior)
myMouseBehavior = false;
else
QGLViewer::mouseReleaseEvent(e);
}

## mousePressEvent()

void mousePressEvent | ( | QMouseEvent * | e | ) |

protected virtual

Overloading of the `QWidget` method.

When the user clicks on the mouse:

- if a mouseGrabber() is defined, qglviewer::MouseGrabber::mousePressEvent() is called,
- otherwise, the camera() or the manipulatedFrame() interprets the mouse displacements, depending on mouse bindings.

Mouse bindings customization can be achieved using setMouseBinding() and setWheelBinding(). See the mouse page for a complete description of mouse bindings.

See the mouseMoveEvent() documentation for an example of more complex mouse behavior customization using overloading.

Note
  When the mouseGrabber() is a manipulatedFrame(), the modifier keys are not taken into account. This allows for a direct manipulation of the manipulatedFrame() when the mouse hovers, which is probably what is expected.

## mouseReleaseEvent()

void mouseReleaseEvent | ( | QMouseEvent * | e | ) |

protected virtual

Overloading of the `QWidget` method.

Calls the mouseGrabber(), camera() or manipulatedFrame `mouseReleaseEvent` method.

See the mouseMoveEvent() documentation for an example of mouse behavior customization.

## mouseString()

QString mouseString | ( |  | ) | const

virtual

Returns a QString that describes the application mouse bindings, displayed in the help() window `Mouse` tab.

Result is a table that describes custom application mouse binding descriptions defined using setMouseBindingDescription() as well as standard mouse bindings (defined using setMouseBinding() and setWheelBinding()). See the mouse page for details on mouse bindings.

See also helpString() and keyboardString().

## openSnapshotFormatDialog

bool openSnapshotFormatDialog | ( |  | ) |

slot

Opens a dialog that displays the different available snapshot formats.

Then calls setSnapshotFormat() with the selected one (unless the user cancels).

Returns `false` if the user presses the Cancel button and `true` otherwise.

## paintGL()

void paintGL | ( |  | ) |

protected virtual

Main paint method, inherited from `QGLWidget`.

Calls the following methods, in that order:

- preDraw() (or preDrawStereo() if viewer displaysInStereo()) : places the camera in the world coordinate system.
- draw() (or fastDraw() when the camera is manipulated) : main drawing method. Should be overloaded.
- postDraw() : display of visual hints (world axis, FPS...)

## pathKey()

Qt::Key pathKey | ( | unsigned int | index | ) | const

Returns the keyboard key associated to camera Key Frame path `index`.

Default values are F1..F12 for indexes 1..12.

addKeyFrameKeyboardModifiers() (resp. playPathKeyboardModifiers()) define the state key(s) that must be pressed with this key to add a KeyFrame to (resp. to play) the associated Key Frame path. If you quickly press twice the pathKey(), the path is reset (resp. deleted).

Use camera()->keyFrameInterpolator( `index` ) to retrieve the KeyFrameInterpolator that defines the path.

If several keys are binded to a given `index` (see setPathKey()), one of them is returned. Returns `0` if no key is associated with this index.

See also the keyboard page.

## playPathKeyboardModifiers()

Qt::KeyboardModifiers playPathKeyboardModifiers | ( |  | ) | const

Returns the keyboard modifiers that must be pressed with a pathKey() to play a camera KeyFrame path.

It can be `Qt::NoModifier`, `Qt::ControlModifier`, `Qt::ShiftModifier`, `Qt::AltModifier`, `Qt::MetaModifier` or a combination of these (using the bitwise '|' operator).

Default value is Qt::NoModifier. Defined using setPlayPathKeyboardModifiers().

See also addKeyFrameKeyboardModifiers().

## pointSelected

void pointSelected | ( | const QMouseEvent * | e | ) |

signal

Signal emitted by select().

Connect this signal to your selection method or overload select(), or more probably simply drawWithNames().

## postDraw()

void postDraw | ( |  | ) |

protected virtual

Called after draw() to draw viewer visual hints.

Default implementation displays axis, grid, FPS... when the respective flags are sets.

See the multiSelect and thumbnail examples for an overloading illustration.

The GLContext (color, LIGHTING, BLEND...) is not modified by this method, so that in draw(), the user can rely on the OpenGL context he defined. Respect this convention (by pushing/popping the different attributes) if you overload this method.

## postSelection()

virtual void postSelection | ( | const QPoint & | point | ) |

protected virtual

This method is called at the end of the select() procedure. It should finalize the selection process and update the data structure/interface/computation/display... according to the newly selected entity.

The default implementation is empty. Overload this method if needed, and use selectedName() to retrieve the selected entity name (returns -1 if no object was selected). See the select example for an illustration.

## preDraw()

void preDraw | ( |  | ) |

protected virtual

Sets OpenGL state before draw().

Default behavior clears screen and sets the projection and modelView matrices:

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
camera()->loadProjectionMatrix();
camera()->loadModelViewMatrix();

Emits the drawNeeded() signal once this is done (see the callback example).

## preDrawStereo()

void preDrawStereo | ( | bool | leftBuffer = `true` | ) |

protected virtual

Called before draw() (instead of preDraw()) when viewer displaysInStereo().

Same as preDraw() except that the glDrawBuffer() is set to `GL_BACK_LEFT` or `GL_BACK_RIGHT` depending on `leftBuffer`, and it uses qglviewer::Camera::loadProjectionMatrixStereo() and qglviewer::Camera::loadModelViewMatrixStereo() instead.

## qglClearColor()

void qglClearColor | ( | const QColor & | color | ) | const

Calls `glClearColor`. See QGLWidget documentation.

## qglColor()

void qglColor | ( | const QColor & | color | ) | const

Calls `glColor3`. See QGLWidget::qglColor().

## QGLViewerIndex()

static int QGLViewerIndex | ( | const QGLViewer *const | viewer | ) |

static

Returns the index of the QGLViewer `viewer` in the QGLViewerPool(). This index in unique and can be used to identify the different created QGLViewers (see stateFileName() for an application example).

When a QGLViewer is deleted, the QGLViewers' indexes are preserved and NULL is set for that index. When a QGLViewer is created, it is placed in the first available position in that list. Returns -1 if the QGLViewer could not be found (which should not be possible).

## QGLViewerPool()

static const QList<QGLViewer*>& QGLViewerPool | ( |  | ) |

static

Returns a `QList` that contains pointers to all the created QGLViewers. Note that this list may contain `NULL` pointers if the associated viewer has been deleted.

Can be useful to apply a method or to connect a signal to all the viewers:

foreach (QGLViewer* viewer, QGLViewer::QGLViewerPool())
connect(myObject, SIGNAL(IHaveChangedSignal()), viewer, SLOT(update()));

Attention
  With Qt version 3, this method returns a `QPtrList` instead. Use a `QPtrListIterator` to iterate on the list instead.

## resize

virtual void resize | ( | int | width,
|  | int | height
| ) |  |

virtual slot

Resizes the widget to size `width` by `height` pixels. See also width() and height().

## resizeGL()

void resizeGL | ( | int | width,
|  | int | height
| ) |  |

protected virtual

Callback method used when the widget size is modified.

If you overload this method, first call the inherited method. Also called when the widget is created, before its first display.

## restoreStateFromFile

bool restoreStateFromFile | ( |  | ) |

virtual slot

Restores the QGLViewer state from the stateFileName() file using initFromDOMElement().

States are saved using saveStateToFile(), which is automatically called on viewer exit.

Returns `true` when the restoration is successful. Possible problems are an non existing or unreadable stateFileName() file, an empty stateFileName() or an XML syntax error.

A manipulatedFrame() should be defined before calling this method, so that its state can be restored. Initialization code put after this function will override saved values:

void Viewer::init()
{
// Default initialization goes here (including the declaration of a possible manipulatedFrame).
if (!restoreStateFromFile())
showEntireScene(); // Previous state cannot be restored: fit camera to scene.
// Specific initialization that overrides file savings goes here.
}

## saveSnapshot [1/2]

void saveSnapshot | ( | bool | automatic = `true`,
|  | bool | overwrite = `false`
| ) |  |

slot

Saves a snapshot of the current image displayed by the widget.

Options are set using snapshotFormat(), snapshotFileName() and snapshotQuality(). For non vectorial image formats, the image size is equal to the current viewer's dimensions (see width() and height()). See snapshotFormat() for details on supported formats.

If `automatic` is `false` (or if snapshotFileName() is empty), a file dialog is opened to ask for the file name.

When `automatic` is `true`, the file name is set to `NAME-NUMBER`, where `NAME` is snapshotFileName() and `NUMBER` is snapshotCounter(). The snapshotCounter() is automatically incremented after each snapshot saving. This is useful to create videos from your application:

void Viewer::init()
{
resize(720, 576); // PAL DV format (use 720x480 for NTSC DV)
connect(this, SIGNAL(drawFinished(bool)), SLOT(saveSnapshot(bool)));
}

Then call draw() in a loop (for instance using animate() and/or a camera() KeyFrameInterpolator replay) to create your image sequence.

If you want to create a Quicktime VR panoramic sequence, simply use code like this:

void Viewer::createQuicktime()
{
const int nbImages = 36;
for (int i=0; i<nbImages; ++i)
{
camera()->setOrientation(2.0*M_PI/nbImages, 0.0); // Theta-Phi orientation
showEntireScene();
update(); // calls draw(), which emits drawFinished(), which calls saveSnapshot()
}
}

If snapshotCounter() is negative, no number is appended to snapshotFileName() and the snapshotCounter() is not incremented. This is useful to force the creation of a file, overwriting the previous one.

When `overwrite` is set to `false` (default), a window asks for confirmation if the file already exists. In `automatic` mode, the snapshotCounter() is incremented (if positive) until a non-existing file name is found instead. Otherwise the file is overwritten without confirmation.

The VRender library was written by Cyril Soler (Cyril dot Soler at imag dot fr). If the generated PS or EPS file is not properly displayed, remove the anti-aliasing option in your postscript viewer.

Note
  In order to correctly grab the frame buffer, the QGLViewer window is raised in front of other windows by this method.

## saveSnapshot [2/2]

void saveSnapshot | ( | const QString & | fileName,
|  | bool | overwrite = `false`
| ) |  |

slot

Same as saveSnapshot(), except that it uses `fileName` instead of snapshotFileName().

If `fileName` is empty, opens a file dialog to select the name.

Snapshot settings are set from snapshotFormat() and snapshotQuality().

Asks for confirmation when `fileName` already exists and `overwrite` is `false` (default).

Attention
  If `fileName` is a char* (as is "myFile.jpg"), it may be casted into a `bool`, and the other saveSnapshot() method may be used instead. Pass QString("myFile.jpg") as a parameter to prevent this.

## saveStateToFile

void saveStateToFile | ( |  | ) |

virtual slot

Saves in stateFileName() an XML representation of the QGLViewer state, obtained from domElement().

Use restoreStateFromFile() to restore this viewer state.

This method is automatically called when a viewer is closed (using Escape or using the window's upper right `x` close button). setStateFileName() to `QString::null` to prevent this.

## scaledFont()

QFont scaledFont | ( | const QFont & | font | ) | const

Return a possibly scaled version of `font`, used for snapshot rendering.

From a user's point of view, this method simply returns `font` and can be used transparently.

However when internally rendering a screen snapshot using saveSnapshot(), it returns a scaled version of the font, so that the size of the rendered text on the snapshot is identical to what is displayed on screen, even if the snapshot uses image tiling to create an image of dimensions different from those of the current window. This scaled version will only be used when saveSnapshot() calls your draw() method to generate the snapshot.

All your calls to QGLWidget::renderText() function hence should use this method.

renderText(x, y, z, "My Text", scaledFont(QFont()));

will guarantee that this text will be properly displayed on arbitrary sized snapshots.

Note that this method is not needed if you use drawText() which already calls it internally.

## sceneCenter()

qglviewer::Vec sceneCenter | ( |  | ) | const

Returns the scene center, defined in world coordinates.

See sceneRadius() for details.

Default value is (0,0,0). Simply a wrapper for camera()->sceneCenter(). Set using setSceneCenter().

Do not mismatch this value (that only depends on the scene) with the qglviewer::Camera::pivotPoint().

## sceneRadius()

qreal sceneRadius | ( |  | ) | const

Returns the scene radius.

The entire displayed scene should be included in a sphere of radius sceneRadius(), centered on sceneCenter().

This approximate value is used by the camera() to set qglviewer::Camera::zNear() and qglviewer::Camera::zFar(). It is also used to showEntireScene() or to scale the world axis display..

Default value is 1.0. This method is equivalent to camera()->sceneRadius(). See setSceneRadius().

## select [1/2]

void select | ( | const QMouseEvent * | event | ) |

virtual slot

Simple wrapper method: calls `select`(event->pos()).

Emits `pointSelected(e)` which is useful only if you rely on the Qt signal-slot mechanism and you did not overload QGLViewer. If you choose to derive your own viewer class, simply overload select() (or probably simply drawWithNames(), see the select example) to implement your selection mechanism.

This method is called when you use the SELECT mouse binding(s) (default is Shift + left button). Use setMouseBinding() to change this.

## select [2/2]

void select | ( | const QPoint & | point | ) |

virtual slot

This method performs a selection in the scene from pixel coordinates.

It is called when the user clicks on the SELECT QGLViewer::ClickAction binded button(s) (default is Shift + LeftButton).

This template method successively calls four other methods:

beginSelection(point);
drawWithNames();
endSelection(point);
postSelection(point);

The default implementation of these methods is as follows (see the methods' documentation for more details):

- beginSelection() sets the `GL_SELECT` mode with the appropriate picking matrices. A rectangular frustum (of size defined by selectRegionWidth() and selectRegionHeight()) centered on `point` is created.

- drawWithNames() is empty and should be overloaded. It draws each selectable object of the scene, enclosed by calls to `glPushName()` / `glPopName()` to tag the object with an integer id.

- endSelection() then restores `GL_RENDER` mode and analyzes the selectBuffer() to set in selectedName() the id of the object that was drawn in the region. If several object are in the region, the closest one in the depth buffer is chosen. If no object has been drawn under cursor, selectedName() is set to -1.

- postSelection() is empty and can be overloaded for possible signal/display/interface update.

See the `glSelectBuffer()` man page for details on this `GL_SELECT` mechanism.

This default implementation is quite limited: only the closer object is selected, and only one level of names can be pushed. However, this reveals sufficient in many cases and you usually only have to overload drawWithNames() to implement a simple object selection process. See the select example for an illustration.

If you need a more complex selection process (such as a point, edge or triangle selection, which is easier with a 2 or 3 levels selectBuffer() heap, and which requires a finer depth sorting to privilege point over edge and edges over triangles), overload the endSelection() method. Use setSelectRegionWidth(), setSelectRegionHeight() and setSelectBufferSize() to tune the select buffer configuration. See the multiSelect example for an illustration.

`point` is the center pixel (origin in the upper left corner) of the selection region. Use qglviewer::Camera::convertClickToLine() to transform these coordinates in a 3D ray if you want to perform an analytical intersection.

Attention
  `GL_SELECT` mode seems to report wrong results when used in conjunction with backface culling. If you encounter problems try to `glDisable(GL_CULL_FACE)`.

## selectBuffer()

GLuint* selectBuffer | ( |  | ) |

Returns a pointer to an array of `GLuint`.

This buffer is used by the `GL_SELECT` mode in select() to perform object selection. The buffer size can be modified using setSelectBufferSize(). If you overload endSelection(), you will analyze the content of this buffer. See the `glSelectBuffer()` man page for details.

## selectBufferSize()

int selectBufferSize | ( |  | ) | const

Returns the selectBuffer() size.

See the select() documentation for details. Use setSelectBufferSize() to change this value.

Default value is 4000 (i.e. 1000 objects in selection region, since each object pushes 4 values). This size should be over estimated to prevent a buffer overflow when many objects are drawn under the mouse cursor.

## selectedName()

int selectedName | ( |  | ) | const

Returns the name (an integer value) of the entity that was last selected by select(). This value is set by endSelection(). See the select() documentation for details.

As a convention, this method returns -1 if the selectBuffer() was empty, meaning that no object was selected.

Return value is -1 before the first call to select(). This value is modified using setSelectedName().

## selectRegionHeight()

int selectRegionHeight | ( |  | ) | const

See the selectRegionWidth() documentation. Default value is 3 pixels.

## selectRegionWidth()

int selectRegionWidth | ( |  | ) | const

Returns the width (in pixels) of a selection frustum, centered on the mouse cursor, that is used to select objects.

The height of the selection frustum is defined by selectRegionHeight().

The objects that will be drawn in this region by drawWithNames() will be recorded in the selectBuffer(). endSelection() then analyzes this buffer and setSelectedName() to the name of the closest object. See the gluPickMatrix() documentation for details.

The default value is 3, which is adapted to standard applications. A smaller value results in a more precise selection but the user has to be careful for small feature selection.

See the multiSelect example for an illustration.

## setAddKeyFrameKeyboardModifiers

void setAddKeyFrameKeyboardModifiers | ( | Qt::KeyboardModifiers | modifiers | ) |

virtual slot

Sets the addKeyFrameKeyboardModifiers() value.

## setAnimationPeriod

void setAnimationPeriod | ( | int | period | ) |

slot

Sets the animationPeriod(), in milliseconds.

## setAutoBufferSwap

void setAutoBufferSwap | ( | bool | on | ) |

protected slot

Sets the autoBufferSwap() value.

## setAxisIsDrawn

void setAxisIsDrawn | ( | bool | draw = `true` | ) |

slot

Sets the state of axisIsDrawn(). Emits the axisIsDrawnChanged() signal. See also toggleAxisIsDrawn().

## setBackgroundColor

void setBackgroundColor | ( | const QColor & | color | ) |

slot

Sets the backgroundColor() of the viewer and calls `qglClearColor()`. See also setForegroundColor().

## setCamera

void setCamera | ( | qglviewer::Camera *const | camera | ) |

slot

Associates a new qglviewer::Camera to the viewer.

You should only use this method when you derive a new class from qglviewer::Camera and want to use one of its instances instead of the original class.

It you simply want to save and restore Camera positions, use qglviewer::Camera::addKeyFrameToPath() and qglviewer::Camera::playPath() instead.

This method silently ignores `NULL` `camera` pointers. The calling method is responsible for deleting the previous camera pointer in order to prevent memory leaks if needed.

The sceneRadius() and sceneCenter() of `camera` are set to the current QGLViewer values.

All the `camera` qglviewer::Camera::keyFrameInterpolator() qglviewer::KeyFrameInterpolator::interpolated() signals are connected to the viewer update() slot. The connections with the previous viewer's camera are removed.

## setCameraIsEdited

void setCameraIsEdited | ( | bool | edit = `true` | ) |

slot

Starts (`edit` = `true`, default) or stops (`edit=`false`)` the edition of the camera().

Current implementation is limited to paths display. Get current state using cameraIsEdited().

Attention
  This method sets the qglviewer::Camera::zClippingCoefficient() to 5.0 when `edit` is `true`, so that the Camera paths (see qglviewer::Camera::keyFrameInterpolator()) are not clipped. It restores the previous value when `edit` is `false`.

## setForegroundColor

void setForegroundColor | ( | const QColor & | color | ) |

slot

Sets the foregroundColor() of the viewer, used to draw visual hints. See also setBackgroundColor().

## setFPSIsDisplayed

void setFPSIsDisplayed | ( | bool | display = `true` | ) |

slot

Sets the state of FPSIsDisplayed(). Emits the FPSIsDisplayedChanged() signal. See also toggleFPSIsDisplayed().

## setFullScreen

void setFullScreen | ( | bool | fullScreen = `true` | ) |

slot

Sets the isFullScreen() state.

If the QGLViewer is embedded in an other QWidget (see QWidget::topLevelWidget()), this widget is displayed in full screen instead.

## setGridIsDrawn

void setGridIsDrawn | ( | bool | draw = `true` | ) |

slot

Sets the state of gridIsDrawn(). Emits the gridIsDrawnChanged() signal. See also toggleGridIsDrawn().

## setKeyDescription

void setKeyDescription | ( | unsigned int | key,
|  | QString | description
| ) |  |

slot

Defines a custom keyboard shortcut description, that will be displayed in the help() window `Keyboard` tab.

The `key` definition is given as an `int` using Qt enumerated values. Set an empty `description` to remove a shortcut description:

setKeyDescription(Qt::Key_W, "Toggles wireframe display");
setKeyDescription(Qt::CTRL+Qt::Key_L, "Loads a new scene");
// Removes a description
setKeyDescription(Qt::CTRL+Qt::Key_C, "");

See the keyboardAndMouse example for illustration and the keyboard page for details.

## setManipulatedFrame

void setManipulatedFrame | ( | qglviewer::ManipulatedFrame * | frame | ) |

slot

Sets the viewer's manipulatedFrame().

Several objects can be manipulated simultaneously, as is done the multiSelect example.

Defining the own viewer's camera()->frame() as the manipulatedFrame() is possible and will result in a classical camera manipulation. See the luxo example for an illustration.

Note that a qglviewer::ManipulatedCameraFrame can be set as the manipulatedFrame(): it is possible to manipulate the camera of a first viewer in a second viewer.

## setMouseBinding [1/4]

void setMouseBinding | ( | Qt::KeyboardModifiers | modifiers,
|  | Qt::MouseButton | button,
|  | MouseHandler | handler,
|  | MouseAction | action,
|  | bool | withConstraint = `true`
| ) |  |

slot

Defines a MouseAction binding.

Same as calling setMouseBinding(Qt::Key, Qt::KeyboardModifiers, Qt::MouseButton, MouseHandler, MouseAction, bool), with a key value of Qt::Key(0) (i.e. no regular extra key needs to be pressed to perform this action).

## setMouseBinding [2/4]

void setMouseBinding | ( | Qt::KeyboardModifiers | modifiers,
|  | Qt::MouseButton | button,
|  | ClickAction | action,
|  | bool | doubleClick = `false`,
|  | Qt::MouseButtons | buttonsBefore = `Qt::NoButton`
| ) |  |

slot

Defines a ClickAction binding.

Same as calling setMouseBinding(Qt::Key, Qt::KeyboardModifiers, Qt::MouseButton, ClickAction, bool, Qt::MouseButtons), with a key value of Qt::Key(0) (i.e. no regular key needs to be pressed to activate this action).

## setMouseBinding [3/4]

void setMouseBinding | ( | Qt::Key | key,
|  | Qt::KeyboardModifiers | modifiers,
|  | Qt::MouseButton | button,
|  | MouseHandler | handler,
|  | MouseAction | action,
|  | bool | withConstraint = `true`
| ) |  |

slot

Associates a MouseAction to any mouse `button`, while keyboard `modifiers` and `key` are pressed. The receiver of the mouse events is a MouseHandler (CAMERA or FRAME).

The parameters should read: when the mouse `button` is pressed, while the keyboard `modifiers` and `key` are down, activate `action` on `handler`. Use Qt::NoModifier to indicate that no modifier key is needed, and a `key` value of 0 if no regular key has to be pressed (or simply use setMouseBinding(Qt::KeyboardModifiers, Qt::MouseButton, MouseHandler, MouseAction, bool)).

Use the '|' operator to combine modifiers:

// The R key combined with the Left mouse button rotates the camera in the screen plane.
setMouseBinding(Qt::Key_R, Qt::NoModifier, Qt::LeftButton, CAMERA, SCREEN_ROTATE);
// Alt + Shift and Left button rotates the manipulatedFrame().
setMouseBinding(Qt::AltModifier | Qt::ShiftModifier, Qt::LeftButton, FRAME, ROTATE);

If `withConstraint` is `true` (default), the possible qglviewer::Frame::constraint() of the associated Frame will be enforced during motion.

The list of all possible MouseAction, some binding examples and default bindings are provided in the mouse page.

See the keyboardAndMouse example for an illustration.

If no mouse button is specified, the binding is ignored. If an action was previously associated with this keyboard and button combination, it is silently overwritten (call mouseAction() before to check).

To remove a specific mouse binding, use `NO_MOUSE_ACTION` as the `action`.

See also setMouseBinding(Qt::KeyboardModifiers, Qt::MouseButtons, ClickAction, bool, int), setWheelBinding() and clearMouseBindings().

## setMouseBinding [4/4]

void setMouseBinding | ( | Qt::Key | key,
|  | Qt::KeyboardModifiers | modifiers,
|  | Qt::MouseButton | button,
|  | ClickAction | action,
|  | bool | doubleClick = `false`,
|  | Qt::MouseButtons | buttonsBefore = `Qt::NoButton`
| ) |  |

slot

Associates a ClickAction to a button and keyboard key and modifier(s) combination.

The parameters should read: when `button` is pressed, while the `modifiers` and `key` keys are down, and possibly as a `doubleClick`, then perform `action`. Use Qt::NoModifier to indicate that no modifier key is needed, and a `key` value of 0 if no regular key has to be pressed (or simply use setMouseBinding(Qt::KeyboardModifiers, Qt::MouseButton, ClickAction, bool, Qt::MouseButtons)).

If `buttonsBefore` is specified (valid only when `doubleClick` is `true`), then this (or these) other mouse button(s) has (have) to be pressed before the double click occurs in order to execute `action`.

The list of all possible ClickAction, some binding examples and default bindings are listed in the mouse page. See also the setMouseBinding() documentation.

See the keyboardAndMouse example for an illustration.

The binding is ignored if Qt::NoButton is specified as `buttons`.

See also setMouseBinding(Qt::KeyboardModifiers, Qt::MouseButtons, MouseHandler, MouseAction, bool), setWheelBinding() and clearMouseBindings().

## setMouseBindingDescription [1/2]

void setMouseBindingDescription | ( | Qt::KeyboardModifiers | modifiers,
|  | Qt::MouseButton | button,
|  | QString | description,
|  | bool | doubleClick = `false`,
|  | Qt::MouseButtons | buttonsBefore = `Qt::NoButton`
| ) |  |

slot

Defines a custom mouse binding description, displayed in the help() window's Mouse tab.

Same as calling setMouseBindingDescription(Qt::Key, Qt::KeyboardModifiers, Qt::MouseButton, QString, bool, Qt::MouseButtons), with a key value of Qt::Key(0) (i.e. binding description when no regular key needs to be pressed).

## setMouseBindingDescription [2/2]

void setMouseBindingDescription | ( | Qt::Key | key,
|  | Qt::KeyboardModifiers | modifiers,
|  | Qt::MouseButton | button,
|  | QString | description,
|  | bool | doubleClick = `false`,
|  | Qt::MouseButtons | buttonsBefore = `Qt::NoButton`
| ) |  |

slot

Defines a custom mouse binding description, displayed in the help() window's Mouse tab.

`modifiers` is a combination of Qt::KeyboardModifiers (`Qt::ControlModifier`, `Qt::AltModifier`, `Qt::ShiftModifier`, `Qt::MetaModifier`). Possibly combined using the `"|"` operator.

`button` is one of the Qt::MouseButtons (`Qt::LeftButton`, `Qt::MidButton`, `Qt::RightButton`...).

`doubleClick` indicates whether or not the user has to double click this button to perform the described action. `buttonsBefore` lists the buttons that need to be pressed before the double click.

Set an empty `description` to remove a mouse binding description.

// The R key combined with the Left mouse button rotates the camera in the screen plane.
setMouseBindingDescription(Qt::Key_R, Qt::NoModifier, Qt::LeftButton, "Rotates camera in screen plane");
// A left button double click toggles full screen
setMouseBindingDescription(Qt::NoModifier, Qt::LeftButton, "Toggles full screen mode", true);
// Removes the description of Ctrl+Right button
setMouseBindingDescription(Qt::ControlModifier, Qt::RightButton, "");

Overload mouseMoveEvent() and friends to implement your custom mouse behavior (see the mouseMoveEvent() documentation for an example). See the keyboardAndMouse example for an illustration.

Use setMouseBinding() and setWheelBinding() to change the standard mouse action bindings.

## setMouseGrabber

void setMouseGrabber | ( | qglviewer::MouseGrabber * | mouseGrabber | ) |

slot

Directly defines the mouseGrabber().

You should not call this method directly as it bypasses the qglviewer::MouseGrabber::checkIfGrabsMouse() test performed by mouseMoveEvent().

If the MouseGrabber is disabled (see mouseGrabberIsEnabled()), this method silently does nothing.

## setMouseGrabberIsEnabled()

void setMouseGrabberIsEnabled | ( | const qglviewer::MouseGrabber *const | mouseGrabber,
|  | bool | enabled = `true`
| ) |  |

Sets the mouseGrabberIsEnabled() state.

## setMouseTracking

virtual void setMouseTracking | ( | bool | enable | ) |

virtual slot

Sets the hasMouseTracking() value.

## setPathKey

void setPathKey | ( | int | key,
|  | unsigned int | index = `0`
| ) |  |

virtual slot

Sets the pathKey() associated with the camera Key Frame path `index`.

Several keys can be binded to the same `index`. Use a negated `key` value to delete the binding (the `index` value is then ignored):

// Press 'space' to play/pause/add/delete camera path of index 0.
setPathKey(Qt::Key_Space, 0);
// Remove this binding
setPathKey(-Qt::Key_Space);

## setPlayPathKeyboardModifiers

void setPlayPathKeyboardModifiers | ( | Qt::KeyboardModifiers | modifiers | ) |

virtual slot

Sets the playPathKeyboardModifiers() value.

## setSceneBoundingBox

void setSceneBoundingBox | ( | const qglviewer::Vec & | min,
|  | const qglviewer::Vec & | max
| ) |  |

slot

Convenient way to call setSceneCenter() and setSceneRadius() from a (world axis aligned) bounding box of the scene.

    This is equivalent to:

setSceneCenter((min+max) / 2.0);
setSceneRadius((max-min).norm() / 2.0);

## setSceneCenter

virtual void setSceneCenter | ( | const qglviewer::Vec & | center | ) |

virtual slot

Sets the sceneCenter(), defined in world coordinates.

    \attention The qglviewer::Camera::pivotPoint() is set to the sceneCenter() value by this
    method.

## setSceneRadius

virtual void setSceneRadius | ( | qreal | radius | ) |

virtual slot

Sets the sceneRadius().

    The camera() qglviewer::Camera::flySpeed() is set to 1% of this value by this method. Simple
    wrapper around camera()->setSceneRadius().

## setSelectBufferSize

void setSelectBufferSize | ( | int | size | ) |

slot

Sets the selectBufferSize().

The previous selectBuffer() is deleted and a new one is created.

## setSelectedName

void setSelectedName | ( | int | id | ) |

slot

Set the selectedName() value.

    Used in endSelection() during a selection. You should only call this method if you overload the
    endSelection() method.

## setSelectRegionHeight

void setSelectRegionHeight | ( | int | height | ) |

slot

Sets the selectRegionHeight().

## setSelectRegionWidth

void setSelectRegionWidth | ( | int | width | ) |

slot

Sets the selectRegionWidth().

## setShortcut

void setShortcut | ( | KeyboardAction | action,
|  | unsigned int | key
| ) |  |

slot

Defines the shortcut() that triggers a given QGLViewer::KeyboardAction.

Here are some examples:

// Press 'Q' to exit application
setShortcut(EXIT_VIEWER, Qt::Key_Q);
// Alt+M toggles camera mode
setShortcut(CAMERA_MODE, Qt::ALT + Qt::Key_M);
// The DISPLAY_FPS action is disabled
setShortcut(DISPLAY_FPS, 0);

Only one shortcut can be assigned to a given QGLViewer::KeyboardAction (new bindings replace previous ones). If several KeyboardAction are binded to the same shortcut, only one of them is active.

## setSnapshotCounter

void setSnapshotCounter | ( | int | counter | ) |

slot

Sets the snapshotCounter().

## setSnapshotFileName

void setSnapshotFileName | ( | const QString & | name | ) |

slot

Sets snapshotFileName().

## setSnapshotFormat

void setSnapshotFormat | ( | const QString & | format | ) |

slot

Sets the snapshotFormat().

## setSnapshotQuality

void setSnapshotQuality | ( | int | quality | ) |

slot

Sets the snapshotQuality().

## setStateFileName

void setStateFileName | ( | const QString & | name | ) |

slot

Defines the stateFileName() used by saveStateToFile() and restoreStateFromFile().

    The file name can have an optional prefix directory (no prefix meaning current directory). If the
    directory does not exist, it will be created by saveStateToFile().

// Name depends on the displayed 3D model. Saved in current directory.
setStateFileName(3DModelName() + ".xml");
// Files are stored in a dedicated directory under user's home directory.
setStateFileName(QDir::homeDirPath + "/.config/myApp.xml");

## setStereoDisplay

void setStereoDisplay | ( | bool | stereo = `true` | ) |

slot

Sets the state of displaysInStereo(). See also toggleStereoDisplay().

First checks that the display is able to handle stereovision using QGLWidget::format(). Opens a warning message box in case of failure. Emits the stereoChanged() signal otherwise.

## setTextIsEnabled

void setTextIsEnabled | ( | bool | enable = `true` | ) |

slot

Sets the state of textIsEnabled(). Emits the textIsEnabledChanged() signal. See also toggleTextIsEnabled().

## setWheelBinding [1/2]

void setWheelBinding | ( | Qt::KeyboardModifiers | modifiers,
|  | MouseHandler | handler,
|  | MouseAction | action,
|  | bool | withConstraint = `true`
| ) |  |

slot

Defines a mouse wheel binding.

Same as calling setWheelBinding(Qt::Key, Qt::KeyboardModifiers, MouseHandler, MouseAction, bool), with a key value of Qt::Key(0) (i.e. no regular key needs to be pressed to activate this action).

## setWheelBinding [2/2]

void setWheelBinding | ( | Qt::Key | key,
|  | Qt::KeyboardModifiers | modifiers,
|  | MouseHandler | handler,
|  | MouseAction | action,
|  | bool | withConstraint = `true`
| ) |  |

slot

Associates a MouseAction and a MouseHandler to a mouse wheel event.

This method is very similar to setMouseBinding(), but specific to the wheel.

In the current implementation only ZOOM can be associated with FRAME, while CAMERA can receive ZOOM and MOVE_FORWARD.

The difference between ZOOM and MOVE_FORWARD is that ZOOM speed depends on the distance to the object, while MOVE_FORWARD moves at a constant speed defined by qglviewer::Camera::flySpeed().

## shortcut()

unsigned int shortcut | ( | KeyboardAction | action | ) | const

Returns the keyboard shortcut associated to a given QGLViewer::KeyboardAction.

Result is an `unsigned` `int` defined using Qt enumerated values, as in `Qt::Key_Q` or `Qt::CTRL` + Qt::Key_X. Use Qt::MODIFIER_MASK to separate the key from the state keys. Returns `0` if the KeyboardAction is disabled (not binded). Set using setShortcut().

If you want to define keyboard shortcuts for custom actions (say, open a scene file), overload keyPressEvent() and then setKeyDescription().

These shortcuts and their descriptions are automatically included in the help() window `Keyboard` tab.

See the keyboard page for details and default values and the keyboardAndMouse example for a practical illustration.

## showEntireScene

void showEntireScene | ( |  | ) |

slot

Moves the camera so that the entire scene is visible.

    Simple wrapper around qglviewer::Camera::showEntireScene().

## sizeHint()

virtual QSize sizeHint | ( |  | ) | const

virtual

Returns the recommended size for the QGLViewer. Default value is 600x400 pixels.

## snapshotCounter()

int snapshotCounter | ( |  | ) | const

Returns the value of the counter used to name snapshots in saveSnapshot() when `automatic` is `true`.

Set using setSnapshotCounter(). Default value is 0, and it is incremented after each `automatic` snapshot. See saveSnapshot() for details.

## snapshotFileName()

const QString& snapshotFileName | ( |  | ) | const

Returns the snapshot file name used by saveSnapshot().

This value is used in `automatic` mode (see saveSnapshot()). A dialog is otherwise popped-up to set it.

You can also directly provide a file name using saveSnapshot(const QString&, bool).

If the file name is relative, the current working directory at the moment of the method call is used. Set using setSnapshotFileName().

## snapshotFormat()

const QString& snapshotFormat | ( |  | ) | const

Returns the snapshot file format used by saveSnapshot().

This value is used when saveSnapshot() is passed the `automatic` flag. It is defined using a saveAs pop-up dialog otherwise.

The available formats are those handled by Qt. Classical values are `"JPEG"`, `"PNG"`, `"PPM"`, `"BMP"`. Use the following code to get the actual list:

QList<QByteArray> formatList = QImageReader::supportedImageFormats();
// or with Qt version 2 or 3:
QStringList formatList = QImage::outputFormatList();

If the library was compiled with the vectorial rendering option (default), three additional vectorial formats are available: `"EPS"`, `"PS"` and `"XFIG"`. `"SVG"` and `"PDF"` formats should soon be available. The VRender library was created by Cyril Soler.

Note that the VRender library has some limitations: vertex shader effects are not reproduced and `PASS_THROUGH` tokens are not handled so one can not change point and line size in the middle of a drawing.

Default value is the first supported among "JPEG, PNG, EPS, PS, PPM, BMP", in that order.

This value is set using setSnapshotFormat() or with openSnapshotFormatDialog().

Attention
  No verification is performed on the provided format validity. The next call to saveSnapshot() may fail if the format string is not supported.

## snapshotQuality()

int snapshotQuality | ( |  | ) |

Defines the image quality of the snapshots produced with saveSnapshot().

Values must be in the range -1..100. Use 0 for lowest quality and 100 for highest quality (and larger files). -1 means use Qt default quality. Default value is 95.

Set using setSnapshotQuality(). See also the QImage::save() documentation.

Note
  This value has no impact on the images produced in vectorial format.

## snapshotToClipboard

void snapshotToClipboard | ( |  | ) |

slot

Takes a snapshot of the current display and pastes it to the clipboard.

This action is activated by the KeyboardAction::SNAPSHOT_TO_CLIPBOARD enum, binded to `Ctrl+C` by default.

## startAnimation

void startAnimation | ( |  | ) |

virtual slot

Starts the animation loop. See animationIsStarted().

## startScreenCoordinatesSystem()

void startScreenCoordinatesSystem | ( | bool | upward = `false` | ) | const

virtual

Modify the projection matrix so that drawing can be done directly with 2D screen coordinates.

Once called, the `x` and `y` coordinates passed to `glVertex` are expressed in pixels screen coordinates. The origin (0,0) is in the upper left corner of the widget by default. This follows the Qt standards, so that you can directly use the `pos()` provided by for instance `QMouseEvent`. Set `upward` to `true` to place the origin in the lower left corner, thus following the OpenGL and mathematical standards. It is always possible to switch between the two representations using `newY` = height() - `y`.

You need to call stopScreenCoordinatesSystem() at the end of the drawing block to restore the previous camera matrix.

In practice, this method should be used in draw(). It sets an appropriate orthographic projection matrix and then sets `glMatrixMode` to `GL_MODELVIEW`.

See the screenCoordSystem, multiSelect and backgroundImage examples for an illustration.

You may want to disable `GL_LIGHTING`, to enable `GL_LINE_SMOOTH` or `GL_BLEND` to draw when this method is used.

If you want to link 2D drawings to 3D objects, use qglviewer::Camera::projectedCoordinatesOf() to compute the 2D projection on screen of a 3D point (see the screenCoordSystem example). See also drawText().

In this mode, you should use z values that are in the [0.0, 1.0[ range (0.0 corresponding to the near clipping plane and 1.0 being just beyond the far clipping plane). This interval matches the values that can be read from the z-buffer. Note that if you use the convenient `glVertex2i()` to provide coordinates, the implicit 0.0 z coordinate will make your drawings appear on top of the rest of the scene.

## stateFileName()

QString stateFileName | ( |  | ) | const

Returns the state file name. Default value is ``.qglviewer.xml.

This is the name of the XML file where saveStateToFile() saves the viewer state (camera state, widget geometry, display flags... see domElement()) on exit. Use restoreStateFromFile() to restore this state later (usually in your init() method).

Setting this value to `QString::null` will disable the automatic state file saving that normally occurs on exit.

If more than one viewer are created by the application, this function will return a numbered file name (as in ".qglviewer1.xml", ".qglviewer2.xml"... using QGLViewer::QGLViewerIndex()) for extra viewers. Each viewer will then read back its own information in restoreStateFromFile(), provided that the viewers are created in the same order, which is usually the case.

## stereoChanged

void stereoChanged | ( | bool | on | ) |

signal

This signal is emitted whenever displaysInStereo() changes value.

## stopAnimation

void stopAnimation | ( |  | ) |

virtual slot

Stops animation. See animationIsStarted().

## stopScreenCoordinatesSystem()

void stopScreenCoordinatesSystem | ( |  | ) | const

virtual

Stops the pixel coordinate drawing block started by startScreenCoordinatesSystem().

The `GL_MODELVIEW` and `GL_PROJECTION` matrices modified in startScreenCoordinatesSystem() are restored. `glMatrixMode` is set to `GL_MODELVIEW`.

## textIsEnabled()

bool textIsEnabled | ( |  | ) | const

Returns `true` if text display (see drawText()) is enabled.

Set by setTextIsEnabled() or toggleTextIsEnabled(). This feature conveniently removes all the possibly displayed text, cleaning display. Default value is `true`.

## textIsEnabledChanged

void textIsEnabledChanged | ( | bool | enabled | ) |

signal

This signal is emitted whenever textIsEnabled() changes value.

## timerEvent()

void timerEvent | ( | QTimerEvent * |  | ) |

protected virtual

Overloading of the `QObject` method.

If animationIsStarted(), calls animate() and draw().

## toggleAnimation

void toggleAnimation | ( |  | ) |

slot

Calls startAnimation() or stopAnimation(), depending on animationIsStarted().

## toggleAxisIsDrawn

void toggleAxisIsDrawn | ( |  | ) |

slot

Toggles the state of axisIsDrawn(). See also setAxisIsDrawn().

## toggleCameraIsEdited

void toggleCameraIsEdited | ( |  | ) |

slot

Toggles the state of cameraIsEdited(). See also setCameraIsEdited().

## toggleCameraMode

void toggleCameraMode | ( |  | ) |

slot

Swaps between two predefined camera mouse bindings.

The first mode makes the camera observe the scene while revolving around the qglviewer::Camera::pivotPoint(). The second mode is designed for walkthrough applications and simulates a flying camera.

Practically, the three mouse buttons are respectively binded to:

- In rotate mode: ROTATE, ZOOM, TRANSLATE.
- In fly mode: MOVE_FORWARD, LOOK_AROUND, MOVE_BACKWARD.

The current mode is determined by checking if a mouse button is binded to ROTATE for the CAMERA. The state key that was previously used to move the camera is preserved.

## toggleFPSIsDisplayed

void toggleFPSIsDisplayed | ( |  | ) |

slot

Toggles the state of FPSIsDisplayed(). See also setFPSIsDisplayed().

## toggleFullScreen

void toggleFullScreen | ( |  | ) |

slot

Toggles the state of isFullScreen(). See also setFullScreen().

## toggleGridIsDrawn

void toggleGridIsDrawn | ( |  | ) |

slot

Toggles the state of gridIsDrawn(). See also setGridIsDrawn().

## toggleStereoDisplay

void toggleStereoDisplay | ( |  | ) |

slot

Toggles the state of displaysInStereo(). See setStereoDisplay().

## toggleTextIsEnabled

void toggleTextIsEnabled | ( |  | ) |

slot

Toggles the state of textIsEnabled(). See also setTextIsEnabled().

## updateGL()

virtual void updateGL | ( |  | ) |

virtual

Updates the display. Do not call draw() directly, use this method instead. See QGLWidget documentation.

## viewerInitialized

void viewerInitialized | ( |  | ) |

signal

Signal emitted by the default init() method.

Connect this signal to the methods that need to be called to initialize your viewer or overload init().

## wheelAction()

QGLViewer::MouseAction wheelAction | ( | Qt::Key | key,
|  | Qt::KeyboardModifiers | modifiers
| ) |  | const

Returns the MouseAction (if any) that is performed when using the wheel, when the `modifiers` and `key` keyboard keys are pressed.

Returns NO_MOUSE_ACTION if no such binding has been defined using setWheelBinding().

Same as mouseAction(), but for the wheel action. See also wheelHandler().

## wheelEvent()

void wheelEvent | ( | QWheelEvent * | e | ) |

protected virtual

Overloading of the `QWidget` method.

If defined, the wheel event is sent to the mouseGrabber(). It is otherwise sent according to wheel bindings (see setWheelBinding()).

## wheelHandler()

int wheelHandler | ( | Qt::Key | key,
|  | Qt::KeyboardModifiers | modifiers
| ) |  | const

Returns the MouseHandler (if any) that receives wheel events when the `modifiers` and `key` keyboard keys are pressed.

Returns -1 if no no such binding has been defined using setWheelBinding(). See also wheelAction().

## width()

int width | ( |  | ) | const

Returns viewer's widget width (in pixels). See QGLWidget documentation.