ccOctreeFrustumIntersector Class Reference

Collaboration diagram for ccOctreeFrustumIntersector:

Public Types
enum	OctreeCellVisibility { CELL_OUTSIDE_FRUSTUM = 0 , CELL_INSIDE_FRUSTUM = 1 , CELL_INTERSECT_FRUSTUM = 2 }
	Definition of the state of a cell compared to a frustum. More...

Public Member Functions
	ccOctreeFrustumIntersector ()
	Default constructor.
bool	build (CCCoreLib::DgmOctree *octree)
	Prepares structure for frustum filtering.
OctreeCellVisibility	positionFromFrustum (CCCoreLib::DgmOctree::CellCode truncatedCode, unsigned char level) const
	Returns the cell visibility.
void	computeFrustumIntersectionWithOctree (std::vector< std::pair< unsigned, CCVector3 > > &pointsToTest, std::vector< unsigned > &inCameraFrustum, const float planesCoefficients[6][4], const CCVector3 ptsFrustum[8], const CCVector3 edges[6], const CCVector3 &center)
	Compute intersection between the octree and a frustum and send back the indices of 3D points inside the frustum or in cells intersecting it. More...
void	computeFrustumIntersectionByLevel (unsigned char level, CCCoreLib::DgmOctree::CellCode parentTruncatedCode, OctreeCellVisibility parentResult, const float planesCoefficients[6][4], const CCVector3 ptsFrustum[8], const CCVector3 edges[6], const CCVector3 &center)
	Compute intersection between the octree and the height children cells of a parent cell. More...
OctreeCellVisibility	separatingAxisTest (const CCVector3 &bbMin, const CCVector3 &bbMax, const float planesCoefficients[6][4], const CCVector3 frustumCorners[8], const CCVector3 frustumEdges[6], const CCVector3 &frustumCenter)
	Separating Axis Test. More...

Protected Attributes
CCCoreLib::DgmOctree *	m_associatedOctree
std::unordered_set< CCCoreLib::DgmOctree::CellCode >	m_cellsBuilt [CCCoreLib::DgmOctree::MAX_OCTREE_LEVEL+1]
std::unordered_set< CCCoreLib::DgmOctree::CellCode >	m_cellsInFrustum [CCCoreLib::DgmOctree::MAX_OCTREE_LEVEL+1]
std::unordered_set< CCCoreLib::DgmOctree::CellCode >	m_cellsIntersectFrustum [CCCoreLib::DgmOctree::MAX_OCTREE_LEVEL+1]

Member Enumeration Documentation

OctreeCellVisibility

enum ccOctreeFrustumIntersector::OctreeCellVisibility

Definition of the state of a cell compared to a frustum.

OUTSIDE : the celle is completely outside the frustum (no intersection, no inclusion) INSIDE : the cell is completely inside the frustum INTERSECT : other cases --> the frustum is completely inside the cell OR the frustum and the cell have an intersection

Member Function Documentation

computeFrustumIntersectionByLevel()

void ccOctreeFrustumIntersector::computeFrustumIntersectionByLevel	(	unsigned char	level,
		CCCoreLib::DgmOctree::CellCode	parentTruncatedCode,
		OctreeCellVisibility	parentResult,
		const float	planesCoefficients[6][4],
		const CCVector3	ptsFrustum[8],
		const CCVector3	edges[6],
		const CCVector3 &	center
	)

Compute intersection between the octree and the height children cells of a parent cell.

Parameters

level	current level
parentTruncatedCode	truncated code of the parent cell (at level-1)
parentResult	contains in which class the parent cell has been classified (OUTSIDE, INTERSECTING, INSIDE)
planesCoefficients	coefficients (a, b, c and d) of the six frustum planes (0:right, 1:bottom, 2:left, 3:top, 4:near, 5:far)
ptsFrustum	3D coordinates of the eight corners of the frustum (global coordinates system)
edges	3D coordinates (global coordinates system) of the six director vector of the frustum edges
center	3D coordinates of the frustum center (global coordinates system) ; this is the center of the circumscribed sphere

computeFrustumIntersectionWithOctree()

void ccOctreeFrustumIntersector::computeFrustumIntersectionWithOctree	(	std::vector< std::pair< unsigned, CCVector3 > > &	pointsToTest,
		std::vector< unsigned > &	inCameraFrustum,
		const float	planesCoefficients[6][4],
		const CCVector3	ptsFrustum[8],
		const CCVector3	edges[6],
		const CCVector3 &	center
	)

Compute intersection between the octree and a frustum and send back the indices of 3D points inside the frustum or in cells intersecting it.

Every cells of each level of the octree will be classified as INSIDE, OUTSIDE or INTERSECTING the frustum. Their truncated code are then stored in m_cellsInFrustum (for cells INSIDE) or m_cellsIntersectFrustum (for cells INTERSECTING).

Parameters

pointsToTest	contains the indice and 3D position (global coordinates system) of every 3D points stored in an INTERSECTING cell
inCameraFrustum	contains the indice of every 3D points stored in an INSIDE cell
planesCoefficients	coefficients (a, b, c and d) of the six frustum planes (0:right, 1:bottom, 2:left, 3:top, 4:near, 5:far)
ptsFrustum	3D coordinates of the eight corners of the frustum (global coordinates system)
edges	3D coordinates (global coordinates system) of the six director vector of the frustum edges
center	3D coordinates of the frustum center (global coordinates system) ; this is the center of the circumscribed sphere

separatingAxisTest()

ccOctreeFrustumIntersector::OctreeCellVisibility ccOctreeFrustumIntersector::separatingAxisTest	(	const CCVector3 &	bbMin,
		const CCVector3 &	bbMax,
		const float	planesCoefficients[6][4],
		const CCVector3	frustumCorners[8],
		const CCVector3	frustumEdges[6],
		const CCVector3 &	frustumCenter
	)

Separating Axis Test.

See "Detecting intersection of a rectangular solid and a convex polyhedron" of Ned Greene See "OBBTree: A Hierarchical Structure for Rapid Interference Detection" of S. Gottschalk, M. C. Lin and D. Manocha

Parameters

bbMin	minimum coordinates of the cell
bbMax	maximum coordinates of the cell
planesCoefficients	coefficients (a, b, c and d) of the six frustum planes (0:right, 1:bottom, 2:left, 3:top, 4:near, 5:far)
frustumCorners	3D coordinates of the eight corners of the frustum (global coordinates system)
frustumEdges	3D coordinates (global coordinates system) of the six director vector of the frustum edges
frustumCenter	3D coordinates of the frustum center (global coordinates system) ; this is the center of the circumscribed sphere

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The documentation for this class was generated from the following files:

• ccCameraSensor.h
• ccCameraSensor.cpp