// Copyright (C) 2002-2010 Nikolaus Gebhardt
// This file is part of the "Irrlicht Engine".
// For conditions of distribution and use, see copyright notice in irrlicht.h

#ifndef __I_TRIANGLE_SELECTOR_H_INCLUDED__
#define __I_TRIANGLE_SELECTOR_H_INCLUDED__

#include "IReferenceCounted.h"
#include "triangle3d.h"
#include "aabbox3d.h"
#include "matrix4.h"
#include "line3d.h"

namespace irr
{
namespace scene
{

class ISceneNode;

//! Interface to return triangles with specific properties.
/** Every ISceneNode may have a triangle selector, available with
ISceneNode::getTriangleScelector() or ISceneManager::createTriangleSelector.
This is used for doing collision detection: For example if you know, that a
collision may have happened in the area between (1,1,1) and (10,10,10), you
can get all triangles of the scene node in this area with the
ITriangleSelector easily and check every triangle if it collided. */
class ITriangleSelector : public virtual IReferenceCounted
{
public:

	//! Destructor
	virtual ~ITriangleSelector() {}

	//! Returns amount of all available triangles in this selector
	virtual s32 getTriangleCount() const = 0;

	//! Gets the triangles for one associated node.
	/**
	This returns all triangles for one scene node associated with this
	selector.  If there is more than one scene node associated (e.g. for
	an IMetaTriangleSelector) this this function may be called multiple
	times to retrieve all triangles.
	\param triangles: Array where the resulting triangles will be
	written to.
	\param arraySize: Size of the target array.
	\param outTriangleCount: Amount of triangles which have been written
	into the array.
	\param transform: Pointer to matrix for transforming the triangles
	before they are returned. Useful for example to scale all triangles
	down into an ellipsoid space. If this pointer is null, no
	transformation will be done. */
	virtual void getTriangles(core::triangle3df* triangles, s32 arraySize,
		s32& outTriangleCount, const core::matrix4* transform=0) const = 0;

	//! Gets the triangles for one associated node which lie or may lie within a specific bounding box.
	/**
	This returns all triangles for one scene node associated with this
	selector.  If there is more than one scene node associated (e.g. for
	an IMetaTriangleSelector) this this function may be called multiple
	times to retrieve all triangles.

	This method will return at least the triangles that intersect the box,
	but may return other triangles as well.
	\param triangles: Array where the resulting triangles will be written
	to.
	\param arraySize: Size of the target array.
	\param outTriangleCount: Amount of triangles which have been written
	into the array.
	\param box: Only triangles which are in this axis aligned bounding box
	will be written into the array.
	\param transform: Pointer to matrix for transforming the triangles
	before they are returned. Useful for example to scale all triangles
	down into an ellipsoid space. If this pointer is null, no
	transformation will be done. */
	virtual void getTriangles(core::triangle3df* triangles, s32 arraySize,
		s32& outTriangleCount, const core::aabbox3d<f32>& box,
		const core::matrix4* transform=0) const = 0;

	//! Gets the triangles for one associated node which have or may have contact with a 3d line.
	/**
	This returns all triangles for one scene node associated with this
	selector.  If there is more than one scene node associated (e.g. for
	an IMetaTriangleSelector) this this function may be called multiple
	times to retrieve all triangles.
	
	Please note that unoptimized triangle selectors also may return
	triangles which are not in contact at all with the 3d line.
	\param triangles: Array where the resulting triangles will be written
	to.
	\param arraySize: Size of the target array.
	\param outTriangleCount: Amount of triangles which have been written
	into the array.
	\param line: Only triangles which may be in contact with this 3d line
	will be written into the array.
	\param transform: Pointer to matrix for transforming the triangles
	before they are returned. Useful for example to scale all triangles
	down into an ellipsoid space. If this pointer is null, no
	transformation will be done. */
	virtual void getTriangles(core::triangle3df* triangles, s32 arraySize,
		s32& outTriangleCount, const core::line3d<f32>& line,
		const core::matrix4* transform=0) const = 0;

	//! Return the scene node associated with a given triangle.
	/**
	This allows you to find which scene node (potentially of several) is
	associated with a specific triangle.

	\param triangleIndex: the index of the triangle for which you want to find
	the associated scene node.
	\return The scene node associated with that triangle.
	*/
	virtual const ISceneNode* getSceneNodeForTriangle(u32 triangleIndex) const = 0;

};

} // end namespace scene
} // end namespace irr


#endif

