Offscreen Buffers

## Offscreen Buffers Offscreen Buffers — Fuctions for creating and manipulating offscreen frame buffer objects |

## Synopsis

    CoglHandle          cogl_offscreen_new_to_texture       (CoglHandle handle);
    CoglHandle          cogl_offscreen_ref                  (CoglHandle handle);
    void                cogl_offscreen_unref                (CoglHandle handle);
    gboolean            cogl_is_offscreen                   (CoglHandle handle);
    void                cogl_set_draw_buffer                (CoglBufferTarget target,
                                                             CoglHandle offscreen);
    void                cogl_pop_draw_buffer                (void);
    void                cogl_push_draw_buffer               (void);

## Description

Cogl allows creating and operating on offscreen render targets.

## Details

### cogl_offscreen_new_to_texture ()

    CoglHandle          cogl_offscreen_new_to_texture       (CoglHandle handle);

This creates an offscreen buffer object using the given texture as the primary color buffer. It doesn't just initialize the contents of the offscreen buffer with the texture; they are tightly bound so that drawing to the offscreen buffer effectivly updates the contents of the given texture. You don't need to destroy the offscreen buffer before you can use the texture again.

Note: This does not work with sliced Cogl textures.

`handle` : | A CoglHandle for a Cogl texture
Returns : | a CoglHandle for the new offscreen buffer or `COGL_INVALID_HANDLE` if it wasn't possible to create the buffer.

### cogl_offscreen_ref ()

    CoglHandle          cogl_offscreen_ref                  (CoglHandle handle);

Increments the reference count on the offscreen buffer.

`handle` : | A CoglHandle for an offscreen buffer
Returns : | For convenience it returns the given CoglHandle

### cogl_offscreen_unref ()

    void                cogl_offscreen_unref                (CoglHandle handle);

Decreases the reference count for the offscreen buffer and frees it when the count reaches 0.

`handle` : | A CoglHandle for an offscreen buffer

### cogl_is_offscreen ()

    gboolean            cogl_is_offscreen                   (CoglHandle handle);

Gets whether the given handle references an existing offscreen buffer object.

`handle` : | A CoglHandle for an offscreen buffer
Returns : | `TRUE` if the handle references an offscreen buffer, `FALSE` otherwise

### cogl_set_draw_buffer ()

    void                cogl_set_draw_buffer                (CoglBufferTarget target,
                                                             CoglHandle offscreen);

This redirects all subsequent drawing to the specified draw buffer. This can either be an offscreen buffer created with `cogl_offscreen_new_to_texture()` or you can revert to your original on screen window buffer.

`target` : | A CoglBufferTarget that specifies what kind of draw buffer you are setting as the render target.
`offscreen` : | If you are setting a draw buffer of type COGL_OFFSCREEN_BUFFER then this is a CoglHandle for the offscreen buffer.

### cogl_pop_draw_buffer ()

    void                cogl_pop_draw_buffer                (void);

Restore `cogl_set_draw_buffer()` state.

### cogl_push_draw_buffer ()

    void                cogl_push_draw_buffer               (void);

Save `cogl_set_draw_buffer()` state.