C++ class MinSG::States::HOMRenderer
HOMRenderer

public

Inheritance Graph

graph BT
	HOMRenderer
	HOMRenderer --> State
	click HOMRenderer "classMinSG_1_1HOMRenderer"
	click State "classMinSG_1_1State"

Description

Occlusion culling renderer which implements Hierarchical Occlusion Maps (HOM) presented in the article mentioned below.

Author: Benjamin Eikel

Date: 2008-09-07 (original as AbstractOctreeRenderer), 2009-07-24 (porting to State )

See also: http://portal.acm.org/citation.cfm?doid=258734.258781

Protected Attributes

GroupNode *	rootNode
unsigned int	sideLength
unsigned int	numLevels
std::vector< Util::Reference < Rendering::Texture > >	homPyramid
float	maxOccluderDepth
bool	showOnlyOccluders
bool	showHOMPyramid
bool	showCulledGeometry
float	minOccluderSize
unsigned int	maxOccluderComplexity
unsigned long	triangleLimit
Util::Reference < Rendering::FBO >	fbo OpenGL frame buffer object for off-screen rendering.
std::deque< GeometryNode * >	occluderDatabase
Util::Reference < Rendering::Shader >	occluderShader
unsigned int	pyramidTests
unsigned int	pyramidTestsVisible
unsigned int	pyramidTestsInvisible
unsigned int	culledGeometry

Public Functions

	HOMRenderer(unsigned int pyramidSize)
	HOMRenderer(const HOMRenderer & source) Copy constructor.
	HOMRenderer( HOMRenderer && void) Move constructor.
	~HOMRenderer() Destructor. Frees the HOM pyramid memory.
void	initOccluderDatabase() Collect possible occluders into the occluder-database.
bool	setSideLength(unsigned int pyramidSize)
unsigned int	getSideLength() const
void	setMaxOccluderDepth(float maxDepth)
float	getMaxOccluderDepth() const
void	setShowOnlyOccluders(bool onlyOccluders)
bool	getShowOnlyOccluders() const
void	setShowHOMPyramid(bool showPyramid)
bool	getShowHOMPyramid() const
void	setShowCulledGeometry(bool showCulled)
bool	getShowCulledGeometry() const
void	setMinOccluderSize(float minSize)
float	getMinOccluderSize() const
void	setMaxOccluderComplexity(unsigned int maxComplexity)
unsigned int	getMaxOccluderComplexity() const
void	setTriangleLimit(unsigned long limit)
unsigned long	getTriangleLimit() const
HOMRenderer *	clone() const Create a duplicate of this State object.

Protected Functions

void	setupHOMPyramid( Rendering::RenderingContext & context)
void	setupShader()
void	clearOccluderDatabase()
void	cleanupHOMPyramid()
void	selectOccluders(std::deque< SelectedOccluder > & occluders, AbstractCameraNode * camera) const
double	drawOccluders(const std::deque< SelectedOccluder > & occluders, FrameContext & context) const
bool	isAreaVisible(unsigned int level, unsigned int minX, unsigned int maxX, unsigned int minY, unsigned int maxY, unsigned int bMinX, unsigned int bMaxX, unsigned int bMinY, unsigned int bMaxY) const
int	process( Node * node, const Geometry::Vec3f & cameraPos, const Geometry::Vec3f & cameraDir, float zPlane, FrameContext & rendContext, const RenderParam & rp, const Geometry::Matrix4x4f & cameraMatrix, const Geometry::Matrix4x4f & projectionMatrix)

---

Documentation

variable
MinSG::HOMRenderer::rootNode

protected

GroupNode * rootNode

Root node of the scene graph which should be rendered.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:181}

---

variable
MinSG::HOMRenderer::sideLength

protected

unsigned int sideLength

Side length in pixels of the highest resolution HOM. The value has to be a power of two and greater or equal four.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:187}

---

variable
MinSG::HOMRenderer::numLevels

protected

unsigned int numLevels

Number of the levels in the HOM pyramid. Calculated from thesideLength.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:193}

---

variable
MinSG::HOMRenderer::homPyramid

protected

std::vector< Util::Reference < Rendering::Texture > > homPyramid

Array of HOMs. At level 0 (index 0) there is the highest resolution HOM. The size of the HOMs is halved with each level until it reaches size 4 x 4 pixels.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:200}

---

variable
MinSG::HOMRenderer::maxOccluderDepth

protected

float maxOccluderDepth

Set the maximum z value for occluders. Occluders which are further away should not be rendered anymore.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:206}

---

variable
MinSG::HOMRenderer::showOnlyOccluders

protected

bool showOnlyOccluders

Instead of rendering the scene only show all occluders in the database.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:212}

---

variable
MinSG::HOMRenderer::showHOMPyramid

protected

bool showHOMPyramid

Render the current HOM pyramid.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:217}

---

variable
MinSG::HOMRenderer::showCulledGeometry

protected

bool showCulledGeometry

Render the geometry which was culled by the occlusion culling algorithm.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:223}

---

variable
MinSG::HOMRenderer::minOccluderSize

protected

float minOccluderSize

Minimum projected size of an object selected as an occluder (size of bounding sphere).

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:229}

---

variable
MinSG::HOMRenderer::maxOccluderComplexity

protected

unsigned int maxOccluderComplexity

Maximum number of triangles of an object selected as an occluder.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:234}

---

variable
MinSG::HOMRenderer::triangleLimit

protected

unsigned long triangleLimit

Maximum number of triangles rendered in one frame for occlusion map generation.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:240}

---

variable
MinSG::HOMRenderer::fbo

protected

Util::Reference < Rendering::FBO > fbo

OpenGL frame buffer object for off-screen rendering.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:243}

---

variable
MinSG::HOMRenderer::occluderDatabase

protected

std::deque< GeometryNode * > occluderDatabase

List containing only occluders.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:248}

---

variable
MinSG::HOMRenderer::occluderShader

protected

Util::Reference < Rendering::Shader > occluderShader

Shader used for rendering the occluders for the HOM.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:253}

---

variable
MinSG::HOMRenderer::pyramidTests

protected

unsigned int pyramidTests

Storage for statistics.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:258}

---

variable
MinSG::HOMRenderer::pyramidTestsVisible

protected

unsigned int pyramidTestsVisible

Storage for statistics.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:263}

---

variable
MinSG::HOMRenderer::pyramidTestsInvisible

protected

unsigned int pyramidTestsInvisible

Storage for statistics.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:268}

---

variable
MinSG::HOMRenderer::culledGeometry

protected

unsigned int culledGeometry

Storage for statistics.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:273}

---

function
MinSG::HOMRenderer::HOMRenderer

public

HOMRenderer(	unsigned int	pyramidSize )

Default constructor. Reservers memory for the HOM pyramid and sets default values for members.

Parameters

pyramidSize

Side length of the HOM pyramid in pixels. It has to be greater or equal four and a power of two.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:66}

---

function
MinSG::HOMRenderer::HOMRenderer

public

HOMRenderer(	const HOMRenderer &	source )

Copy constructor.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:69}

---

function
MinSG::HOMRenderer::HOMRenderer

public

HOMRenderer(	HOMRenderer &&	void )

Move constructor.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:72}

---

function
MinSG::HOMRenderer::~HOMRenderer

public

virtual

~HOMRenderer(	)

Destructor. Frees the HOM pyramid memory.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:75}

---

function
MinSG::HOMRenderer::initOccluderDatabase

public

void initOccluderDatabase(	)

Collect possible occluders into the occluder-database.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:78}

---

function
MinSG::HOMRenderer::setSideLength

public

bool setSideLength(	unsigned int	pyramidSize )

Change the pyramid size if the parameter is valid.

Parameters

pyramidSize

Side length of the HOM pyramid in pixels. It has to be greater or equal four and a power of two.

Returns

trueif the side length was changed,falseotherwise.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:88}

---

function
MinSG::HOMRenderer::getSideLength

public

const

inline

unsigned int getSideLength(	) const

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:89}

---

function
MinSG::HOMRenderer::setMaxOccluderDepth

public

inline

void setMaxOccluderDepth(	float	maxDepth )

Set the maximum z value for occluders. Occluders which are further away should not be rendered anymore.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:97}

---

function
MinSG::HOMRenderer::getMaxOccluderDepth

public

const

inline

float getMaxOccluderDepth(	) const

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:100}

---

function
MinSG::HOMRenderer::setShowOnlyOccluders

public

inline

void setShowOnlyOccluders(	bool	onlyOccluders )

Specify if instead of rendering the scene only all occluders in the database should be shown.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:109}

---

function
MinSG::HOMRenderer::getShowOnlyOccluders

public

const

inline

bool getShowOnlyOccluders(	) const

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:112}

---

function
MinSG::HOMRenderer::setShowHOMPyramid

public

inline

void setShowHOMPyramid(	bool	showPyramid )

Specify if the current HOM pyramid should be shown.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:120}

---

function
MinSG::HOMRenderer::getShowHOMPyramid

public

const

inline

bool getShowHOMPyramid(	) const

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:123}

---

function
MinSG::HOMRenderer::setShowCulledGeometry

public

inline

void setShowCulledGeometry(	bool	showCulled )

Specify if the geometry which was culled by the occlusion culling algorithm should be shown.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:132}

---

function
MinSG::HOMRenderer::getShowCulledGeometry

public

const

inline

bool getShowCulledGeometry(	) const

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:135}

---

function
MinSG::HOMRenderer::setMinOccluderSize

public

inline

void setMinOccluderSize(	float	minSize )

Set the minimum projected size of an object to get selected as an occluder (size of bounding sphere).

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:144}

---

function
MinSG::HOMRenderer::getMinOccluderSize

public

const

inline

float getMinOccluderSize(	) const

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:147}

---

function
MinSG::HOMRenderer::setMaxOccluderComplexity

public

inline

void setMaxOccluderComplexity(	unsigned int	maxComplexity )

Set the maximum number of triangles of an object to get selected as an occluder.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:156}

---

function
MinSG::HOMRenderer::getMaxOccluderComplexity

public

const

inline

unsigned int getMaxOccluderComplexity(	) const

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:159}

---

function
MinSG::HOMRenderer::setTriangleLimit

public

inline

void setTriangleLimit(	unsigned long	limit )

Set the maximum number of triangles rendered in one frame for occlusion map generation.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:168}

---

function
MinSG::HOMRenderer::getTriangleLimit

public

const

inline

unsigned long getTriangleLimit(	) const

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:171}

---

function
MinSG::HOMRenderer::clone

public

const

virtual

HOMRenderer * clone(	) const

Create a duplicate of this State object.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:175}

---

function
MinSG::HOMRenderer::setupHOMPyramid

protected

void setupHOMPyramid(	Rendering::RenderingContext &	context )

Reserves the memory for the HOM pyramid.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:278}

---

function
MinSG::HOMRenderer::setupShader

protected

void setupShader(	)

Creates the Shader.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:283}

---

function
MinSG::HOMRenderer::clearOccluderDatabase

protected

void clearOccluderDatabase(	)

Clear the occluder-database.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:288}

---

function
MinSG::HOMRenderer::cleanupHOMPyramid

protected

void cleanupHOMPyramid(	)

Frees the memory for the HOM pyramid.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:293}

---

function
MinSG::HOMRenderer::selectOccluders

protected

const

void selectOccluders(	std::deque< SelectedOccluder > &	occluders,
	AbstractCameraNode *	camera
) const

Select occluders in frustum.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:304}

---

function
MinSG::HOMRenderer::drawOccluders

protected

const

double drawOccluders(	const std::deque< SelectedOccluder > &	occluders,
	FrameContext &	context
) const

Draw selected occluders.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:309}

---

function
MinSG::HOMRenderer::isAreaVisible

protected

const

bool isAreaVisible(	unsigned int	level,
	unsigned int	minX,
	unsigned int	maxX,
	unsigned int	minY,
	unsigned int	maxY,
	unsigned int	bMinX,
	unsigned int	bMaxX,
	unsigned int	bMinY,
	unsigned int	bMaxY
) const

Checks the given area inside the HOM pyramid and determines if the area is visible.

Parameters

level

Level to do the area check in.

minX

Left border of the area in the given level.

maxX

Right border of the area in the given level.

minY

Bottom border of the area in the given level.

maxY

Top border of the area in the given level.

bMinX

Left border of the area in the bottom level.

bMaxX

Right border of the area in the bottom level.

bMinY

Bottom border of the area in the bottom level.

bMaxY

Top border of the area in the bottom level.

Returns

trueif the area is visible andfalseif the area is hidden.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:327}

---

function
MinSG::HOMRenderer::process

protected

int process(	Node *	node,
	const Geometry::Vec3f &	cameraPos,
	const Geometry::Vec3f &	cameraDir,
	float	zPlane,
	FrameContext &	rendContext,
	const RenderParam &	rp,
	const Geometry::Matrix4x4f &	cameraMatrix,
	const Geometry::Matrix4x4f &	projectionMatrix
)

Used when displaying the scene with the occlusion culling algorithm. It checks if a node is visible. If it is, it draws it and traverses the children. Otherwise the traversal is stopped at that node.

Parameters

node

Node currently visited.

cameraPos

Absolute position of the camera.

cameraDir

Normalized viewing direction of the camera.

zPlane

Maximum z coordinate of occluders that are used in the current frame.

rendContext

Current rendering context which should be used for displaying.

rendFlags

Flags which should be used for displaying.

cameraMatrix

Camera matrix that was used to render the occluders.

projectionMatrix

Projection matrix that was used to render the occluders.

Returns

Status code indicating if the traversal should be continued.

_{Defined in MinSG/Ext/OcclusionCulling/HOMRenderer.h:352}

---