Ogre::TerrainQuadTreeNode Class Reference
[Terrain]

A node in a quad tree used to store a patch of terrain. More...

#include <OgreTerrainQuadTreeNode.h>

Inheritance diagram for Ogre::TerrainQuadTreeNode:

Classes
struct	LodLevel
class	Movable
	MovableObject implementation to provide the hook to the scene. More...
class	Rend
	Hook to the render queue. More...
struct	VertexDataRecord
Public Types
typedef vector< LodLevel * >::type	LodLevelList
Public Member Functions
	TerrainQuadTreeNode (Terrain terrain, TerrainQuadTreeNode parent, uint16 xoff, uint16 yoff, uint16 size, uint16 lod, uint16 depth, uint16 quadrant)
	Constructor.
virtual	~TerrainQuadTreeNode ()
uint16	getXOffset () const
	Get the horizontal offset into the main terrain data of this node.
uint16	getYOffset () const
	Get the vertical offset into the main terrain data of this node.
bool	isLeaf () const
	Is this a leaf node (no children).
uint16	getBaseLod () const
	Get the base LOD level this node starts at (the highest LOD it handles).
uint16	getLodCount () const
	Get the number of LOD levels this node can represent itself (only > 1 for leaf nodes).
TerrainQuadTreeNode *	getChild (unsigned short child) const
	Get child node.
TerrainQuadTreeNode *	getParent () const
	Get parent node.
Terrain *	getTerrain () const
	Get ultimate parent terrain.
void	prepare ()
	Prepare node and children (perform CPU tasks, may be background thread).
void	prepare (StreamSerialiser &stream)
	Prepare node from a stream.
void	load ()
	Load node and children (perform GPU tasks, will be render thread).
void	unload ()
	Unload node and children (perform GPU tasks, will be render thread).
void	unprepare ()
	Unprepare node and children (perform CPU tasks, may be background thread).
void	save (StreamSerialiser &stream)
	Save node to a stream.
const LodLevel *	getLodLevel (uint16 lod)
	Get the LodLevel information for a given lod.
void	preDeltaCalculation (const Rect &rect)
	Notify the node (and children) that deltas are going to be calculated for a given range.
void	notifyDelta (uint16 x, uint16 y, uint16 lod, Real delta)
	Notify the node (and children) of a height delta value.
void	postDeltaCalculation (const Rect &rect)
	Notify the node (and children) that deltas have finished being calculated.
void	finaliseDeltaValues (const Rect &rect)
	Promote the delta values calculated to the runtime ones (this must be called in the main thread).
void	assignVertexData (uint16 treeDepthStart, uint16 treeDepthEnd, uint16 resolution, uint sz)
	Assign vertex data to the tree, from a depth and at a given resolution.
void	useAncestorVertexData (TerrainQuadTreeNode *owner, uint16 treeDepthEnd, uint16 resolution)
	Tell a node that it should use an anscestor's vertex data.
void	updateVertexData (bool positions, bool deltas, const Rect &rect, bool cpuData)
	Tell the node to update its vertex data for a given region.
void	mergeIntoBounds (long x, long y, const Vector3 &pos)
	Merge a point (relative to terrain node) into the local bounds, and that of children if applicable.
void	resetBounds (const Rect &rect)
	Reset the bounds of this node and all its children for the region given.
bool	rectIntersectsNode (const Rect &rect)
	Returns true if the given rectangle overlaps the terrain area that this node references.
bool	rectContainsNode (const Rect &rect)
	Returns true if the given rectangle completely contains the terrain area that this node references.
bool	pointIntersectsNode (long x, long y)
	Returns true if the given point is in the terrain area that this node references.
const AxisAlignedBox &	getAABB () const
	Get the AABB (local coords) of this node.
Real	getBoundingRadius () const
	Get the bounding radius of this node.
const Vector3 &	getLocalCentre () const
	Get the local centre of this node, relative to parent terrain centre.
Real	getMinHeight () const
	Get the minimum height of the node.
Real	getMaxHeight () const
	Get the maximum height of the node.
bool	calculateCurrentLod (const Camera *cam, Real cFactor)
	Calculate appropriate LOD for this node and children.
int	getCurrentLod () const
	Get the current LOD index (only valid after calculateCurrentLod).
bool	isRenderedAtCurrentLod () const
	Returns whether this node is rendering itself at the current LOD level.
bool	isSelfOrChildRenderedAtCurrentLod () const
	Returns whether this node or its children are being rendered at the current LOD level.
void	setCurrentLod (int lod)
	Manually set the current LOD, intended for internal use only.
float	getLodTransition () const
	Get the transition state between the current LOD and the next lower one (only valid after calculateCurrentLod).
void	setLodTransition (float t)
	Manually set the current LOD transition state, intended for internal use only.
Renderable *	_getRenderable ()
	Returns the internal renderable object for this node.
void *	operator new (size_t sz, const char file, int line, const char func)
	operator new, with debug line info
void *	operator new (size_t sz)
void *	operator new (size_t sz, void *ptr)
	placement operator new
void *	operator new[] (size_t sz, const char file, int line, const char func)
	array operator new, with debug line info
void *	operator new[] (size_t sz)
void	operator delete (void *ptr)
void	operator delete (void ptr, void )
void	operator delete (void ptr, const char , int, const char *)
void	operator delete[] (void *ptr)
void	operator delete[] (void ptr, const char , int, const char *)
Static Public Attributes
static unsigned short	POSITION_BUFFER
	Buffer binding used for holding positions.
static unsigned short	DELTA_BUFFER
	Buffer binding used for holding delta values.
Protected Member Functions
void	updateRenderQueue (RenderQueue *queue)
void	visitRenderables (Renderable::Visitor *visitor, bool debugRenderables=false)
const MaterialPtr &	getMaterial (void) const
Technique *	getTechnique (void) const
void	getRenderOperation (RenderOperation &op)
void	getWorldTransforms (Matrix4 *xform) const
Real	getSquaredViewDepth (const Camera *cam) const
const LightList &	getLights (void) const
bool	getCastsShadows (void) const
const VertexDataRecord *	getVertexDataRecord () const
void	createCpuVertexData ()
void	updateVertexBuffer (HardwareVertexBufferSharedPtr &posbuf, HardwareVertexBufferSharedPtr &deltabuf, const Rect &rect)
void	destroyCpuVertexData ()
void	createGpuVertexData ()
void	destroyGpuVertexData ()
void	updateGpuVertexData ()
void	createGpuIndexData ()
void	destroyGpuIndexData ()
void	populateIndexData (uint16 batchSize, IndexData *destData)
void	writePosVertex (bool compress, uint16 x, uint16 y, float height, const Vector3 &pos, float uvScale, float **ppPos)
void	writeDeltaVertex (bool compress, uint16 x, uint16 y, float delta, float deltaThresh, float **ppDelta)
uint16	calcSkirtVertexIndex (uint16 mainIndex, bool isCol)
Protected Attributes
Terrain *	mTerrain
TerrainQuadTreeNode *	mParent
TerrainQuadTreeNode *	mChildren [4]
LodLevelList	mLodLevels
uint16	mOffsetX
uint16	mOffsetY
uint16	mBoundaryX
uint16	mBoundaryY
uint16	mSize
	the number of vertices at the original terrain resolution this node encompasses
uint16	mBaseLod
uint16	mDepth
uint16	mQuadrant
Vector3	mLocalCentre
AxisAlignedBox	mAABB
Real	mBoundingRadius
int	mCurrentLod
unsigned short	mMaterialLodIndex
float	mLodTransition
TerrainQuadTreeNode *	mChildWithMaxHeightDelta
	The child with the largest height delta.
bool	mSelfOrChildRendered
TerrainQuadTreeNode *	mNodeWithVertexData
VertexDataRecord *	mVertexDataRecord
Movable *	mMovable
SceneNode *	mLocalNode
Rend *	mRend
Friends
class	Movable
class	Rend

Detailed Description

A node in a quad tree used to store a patch of terrain.

Remarks:: Algorithm overview:

: Our goal is to perform traditional chunked LOD with geomorphing. But, instead of just dividing the terrain into tiles, we will divide them into a hierarchy of tiles, a quadtree, where any level of the quadtree can be a rendered tile (to the exclusion of its children). The idea is to collect together children into a larger batch with their siblings as LOD decreases, to improve performance.

: The minBatchSize and maxBatchSize parameters on Terrain a key to defining this behaviour. Both values are expressed in vertices down one axis. maxBatchSize determines the number of tiles on one side of the terrain, which is numTiles = (terrainSize-1) / (maxBatchSize-1). This in turn determines the depth of the quad tree, which is sqrt(numTiles). The minBatchSize determines the 'floor' of how low the number of vertices can go in a tile before it has to be grouped together with its siblings to drop any lower. We also do not group a tile with its siblings unless all of them are at this minimum batch size, rather than trying to group them when they all end up on the same 'middle' LOD; this is for several reasons; firstly, tiles hitting the same 'middle' LOD is less likely and more transient if they have different levels of 'roughness', and secondly since we're sharing a vertex / index pool between all tiles, only grouping at the min level means that the number of combinations of buffer sizes for any one tile is greatly simplified, making it easier to pool data. To be more specific, any tile / quadtree node can only have log2(maxBatchSize-1) - log2(minBatchSize-1) + 1 LOD levels (and if you set them to the same value, LOD can only change by going up/down the quadtree). The numbers of vertices / indices in each of these levels is constant for the same (relative) LOD index no matter where you are in the tree, therefore buffers can potentially be reused more easily.

Definition at line 85 of file OgreTerrainQuadTreeNode.h.

Member Typedef Documentation

typedef vector<LodLevel*>::type Ogre::TerrainQuadTreeNode::LodLevelList

Definition at line 149 of file OgreTerrainQuadTreeNode.h.

Constructor & Destructor Documentation

Ogre::TerrainQuadTreeNode::TerrainQuadTreeNode	(	Terrain *	terrain,
		TerrainQuadTreeNode *	parent,
		uint16	xoff,
		uint16	yoff,
		uint16	size,
		uint16	lod,
		uint16	depth,
		uint16	quadrant
	)

Constructor.

Parameters:

	terrain	The ultimate parent terrain
	parent	Optional parent node (in which case xoff, yoff are 0 and size must be entire terrain)
	xoff,off	Offsets from the start of the terrain data in 2D
	size	The size of the node in vertices at the highest LOD
	lod	The base LOD level
	depth	The depth that this node is at in the tree (or convenience)
	quadrant	The index of the quadrant (0, 1, 2, 3)

virtual Ogre::TerrainQuadTreeNode::~TerrainQuadTreeNode ( ) [virtual]

Member Function Documentation

Renderable* Ogre::TerrainQuadTreeNode::_getRenderable ( )

Returns the internal renderable object for this node.

void Ogre::TerrainQuadTreeNode::assignVertexData	(	uint16	treeDepthStart,
		uint16	treeDepthEnd,
		uint16	resolution,
		uint	sz
	)

Assign vertex data to the tree, from a depth and at a given resolution.

Parameters:

	treeDepthStart	The first depth of tree that should use this data, owns the data
	treeDepthEnd	The end of the depth that should use this data (exclusive)
	resolution	The resolution of the data to use (compared to full terrain)
	sz	The size of the data along one edge

uint16 Ogre::TerrainQuadTreeNode::calcSkirtVertexIndex	(	uint16	mainIndex,
		bool	isCol
	)			`[protected]`

bool Ogre::TerrainQuadTreeNode::calculateCurrentLod	(	const Camera *	cam,
		Real	cFactor
	)

Calculate appropriate LOD for this node and children.

Parameters:

	cam	The camera to be used (this should already be the LOD camera)
	cFactor	The cFactor which incorporates the viewport size, max pixel error and lod bias

Returns:: true if this node or any of its children were selected for rendering

void Ogre::TerrainQuadTreeNode::createCpuVertexData ( ) [protected]

void Ogre::TerrainQuadTreeNode::createGpuIndexData ( ) [protected]

void Ogre::TerrainQuadTreeNode::createGpuVertexData ( ) [protected]

void Ogre::TerrainQuadTreeNode::destroyCpuVertexData ( ) [protected]

void Ogre::TerrainQuadTreeNode::destroyGpuIndexData ( ) [protected]

void Ogre::TerrainQuadTreeNode::destroyGpuVertexData ( ) [protected]

void Ogre::TerrainQuadTreeNode::finaliseDeltaValues ( const Rect & rect )

Promote the delta values calculated to the runtime ones (this must be called in the main thread).

const AxisAlignedBox& Ogre::TerrainQuadTreeNode::getAABB ( ) const

Get the AABB (local coords) of this node.

uint16 Ogre::TerrainQuadTreeNode::getBaseLod ( ) const

Get the base LOD level this node starts at (the highest LOD it handles).

Definition at line 108 of file OgreTerrainQuadTreeNode.h.

Real Ogre::TerrainQuadTreeNode::getBoundingRadius ( ) const

Get the bounding radius of this node.

bool Ogre::TerrainQuadTreeNode::getCastsShadows ( void ) const [protected]

TerrainQuadTreeNode* Ogre::TerrainQuadTreeNode::getChild ( unsigned short child ) const

Get child node.

int Ogre::TerrainQuadTreeNode::getCurrentLod ( ) const

Get the current LOD index (only valid after calculateCurrentLod).

Definition at line 243 of file OgreTerrainQuadTreeNode.h.

const LightList& Ogre::TerrainQuadTreeNode::getLights ( void ) const [protected]

const Vector3& Ogre::TerrainQuadTreeNode::getLocalCentre ( ) const

Get the local centre of this node, relative to parent terrain centre.

Definition at line 229 of file OgreTerrainQuadTreeNode.h.

uint16 Ogre::TerrainQuadTreeNode::getLodCount ( ) const

Get the number of LOD levels this node can represent itself (only > 1 for leaf nodes).

const LodLevel* Ogre::TerrainQuadTreeNode::getLodLevel ( uint16 lod )

Get the LodLevel information for a given lod.

Parameters:

lod

The lod level index relative to this classes own list; if you want to use a global lod level, subtract getBaseLod() first. Higher LOD levels are lower detail.

float Ogre::TerrainQuadTreeNode::getLodTransition ( ) const

Get the transition state between the current LOD and the next lower one (only valid after calculateCurrentLod).

Definition at line 251 of file OgreTerrainQuadTreeNode.h.

const MaterialPtr& Ogre::TerrainQuadTreeNode::getMaterial ( void ) const [protected]

Real Ogre::TerrainQuadTreeNode::getMaxHeight ( ) const

Get the maximum height of the node.

Real Ogre::TerrainQuadTreeNode::getMinHeight ( ) const

Get the minimum height of the node.

TerrainQuadTreeNode* Ogre::TerrainQuadTreeNode::getParent ( ) const

Get parent node.

void Ogre::TerrainQuadTreeNode::getRenderOperation ( RenderOperation & op ) [protected]

Real Ogre::TerrainQuadTreeNode::getSquaredViewDepth ( const Camera * cam ) const [protected]

Technique* Ogre::TerrainQuadTreeNode::getTechnique ( void ) const [protected]

Terrain* Ogre::TerrainQuadTreeNode::getTerrain ( ) const

Get ultimate parent terrain.

const VertexDataRecord* Ogre::TerrainQuadTreeNode::getVertexDataRecord ( ) const [protected]

void Ogre::TerrainQuadTreeNode::getWorldTransforms ( Matrix4 * xform ) const [protected]

uint16 Ogre::TerrainQuadTreeNode::getXOffset ( ) const

Get the horizontal offset into the main terrain data of this node.

Definition at line 102 of file OgreTerrainQuadTreeNode.h.

uint16 Ogre::TerrainQuadTreeNode::getYOffset ( ) const

Get the vertical offset into the main terrain data of this node.

Definition at line 104 of file OgreTerrainQuadTreeNode.h.

bool Ogre::TerrainQuadTreeNode::isLeaf ( ) const

Is this a leaf node (no children).

bool Ogre::TerrainQuadTreeNode::isRenderedAtCurrentLod ( ) const

Returns whether this node is rendering itself at the current LOD level.

bool Ogre::TerrainQuadTreeNode::isSelfOrChildRenderedAtCurrentLod ( ) const

Returns whether this node or its children are being rendered at the current LOD level.

void Ogre::TerrainQuadTreeNode::load ( )

Load node and children (perform GPU tasks, will be render thread).

void Ogre::TerrainQuadTreeNode::mergeIntoBounds	(	long	x,
		long	y,
		const Vector3 &	pos
	)

Merge a point (relative to terrain node) into the local bounds, and that of children if applicable.

Parameters:

	x,y	The point on the terrain to which this position corresponds (affects which nodes update their bounds)
	pos	The position relative to the terrain centre

void Ogre::TerrainQuadTreeNode::notifyDelta	(	uint16	x,
		uint16	y,
		uint16	lod,
		Real	delta
	)

Notify the node (and children) of a height delta value.

template<class Alloc >

void Ogre::AllocatedObject< Alloc >::operator delete	(	void *	ptr,
		const char *	,
		int	,
		const char *
	)			`[inherited]`

Definition at line 107 of file OgreMemoryAllocatedObject.h.

template<class Alloc >

void Ogre::AllocatedObject< Alloc >::operator delete	(	void *	ptr,
		void *
	)			`[inherited]`

Definition at line 101 of file OgreMemoryAllocatedObject.h.

template<class Alloc >

void Ogre::AllocatedObject< Alloc >::operator delete ( void * ptr ) [inherited]

Definition at line 95 of file OgreMemoryAllocatedObject.h.

template<class Alloc >

void Ogre::AllocatedObject< Alloc >::operator delete[]	(	void *	ptr,
		const char *	,
		int	,
		const char *
	)			`[inherited]`

Definition at line 118 of file OgreMemoryAllocatedObject.h.

template<class Alloc >

void Ogre::AllocatedObject< Alloc >::operator delete[] ( void * ptr ) [inherited]

Definition at line 112 of file OgreMemoryAllocatedObject.h.

template<class Alloc >

void* Ogre::AllocatedObject< Alloc >::operator new	(	size_t	sz,
		void *	ptr
	)			`[inherited]`

placement operator new

Definition at line 78 of file OgreMemoryAllocatedObject.h.

template<class Alloc >

void* Ogre::AllocatedObject< Alloc >::operator new ( size_t sz ) [inherited]

Definition at line 72 of file OgreMemoryAllocatedObject.h.

template<class Alloc >

void* Ogre::AllocatedObject< Alloc >::operator new	(	size_t	sz,
		const char *	file,
		int	line,
		const char *	func
	)			`[inherited]`

operator new, with debug line info

Definition at line 67 of file OgreMemoryAllocatedObject.h.

template<class Alloc >

void* Ogre::AllocatedObject< Alloc >::operator new[] ( size_t sz ) [inherited]

Definition at line 90 of file OgreMemoryAllocatedObject.h.

template<class Alloc >

void* Ogre::AllocatedObject< Alloc >::operator new[]	(	size_t	sz,
		const char *	file,
		int	line,
		const char *	func
	)			`[inherited]`

array operator new, with debug line info

Definition at line 85 of file OgreMemoryAllocatedObject.h.

bool Ogre::TerrainQuadTreeNode::pointIntersectsNode	(	long	x,
		long	y
	)

Returns true if the given point is in the terrain area that this node references.

Parameters:

x,y

The point in top-level terrain coords

void Ogre::TerrainQuadTreeNode::populateIndexData	(	uint16	batchSize,
		IndexData *	destData
	)			`[protected]`

void Ogre::TerrainQuadTreeNode::postDeltaCalculation ( const Rect & rect )

Notify the node (and children) that deltas have finished being calculated.

void Ogre::TerrainQuadTreeNode::preDeltaCalculation ( const Rect & rect )

Notify the node (and children) that deltas are going to be calculated for a given range.

Remarks:: Based on this call, we can know whether or not to reset the max height.

void Ogre::TerrainQuadTreeNode::prepare ( StreamSerialiser & stream )

Prepare node from a stream.

void Ogre::TerrainQuadTreeNode::prepare ( )

Prepare node and children (perform CPU tasks, may be background thread).

bool Ogre::TerrainQuadTreeNode::rectContainsNode ( const Rect & rect )

Returns true if the given rectangle completely contains the terrain area that this node references.

Parameters:

rect

The region in top-level terrain coords

bool Ogre::TerrainQuadTreeNode::rectIntersectsNode ( const Rect & rect )

Returns true if the given rectangle overlaps the terrain area that this node references.

Parameters:

rect

The region in top-level terrain coords

void Ogre::TerrainQuadTreeNode::resetBounds ( const Rect & rect )

Reset the bounds of this node and all its children for the region given.

Parameters:

rect

The region for which bounds should be reset, in top-level terrain coords

void Ogre::TerrainQuadTreeNode::save ( StreamSerialiser & stream )

Save node to a stream.

void Ogre::TerrainQuadTreeNode::setCurrentLod ( int lod )

Manually set the current LOD, intended for internal use only.

void Ogre::TerrainQuadTreeNode::setLodTransition ( float t )

Manually set the current LOD transition state, intended for internal use only.

void Ogre::TerrainQuadTreeNode::unload ( )

Unload node and children (perform GPU tasks, will be render thread).

void Ogre::TerrainQuadTreeNode::unprepare ( )

Unprepare node and children (perform CPU tasks, may be background thread).

void Ogre::TerrainQuadTreeNode::updateGpuVertexData ( ) [protected]

void Ogre::TerrainQuadTreeNode::updateRenderQueue ( RenderQueue * queue ) [protected]

void Ogre::TerrainQuadTreeNode::updateVertexBuffer	(	HardwareVertexBufferSharedPtr &	posbuf,
		HardwareVertexBufferSharedPtr &	deltabuf,
		const Rect &	rect
	)			`[protected]`

void Ogre::TerrainQuadTreeNode::updateVertexData	(	bool	positions,
		bool	deltas,
		const Rect &	rect,
		bool	cpuData
	)

Tell the node to update its vertex data for a given region.

void Ogre::TerrainQuadTreeNode::useAncestorVertexData	(	TerrainQuadTreeNode *	owner,
		uint16	treeDepthEnd,
		uint16	resolution
	)

Tell a node that it should use an anscestor's vertex data.

Parameters:

	treeDepthEnd	The end of the depth that should use this data (exclusive)
	resolution	The resolution of the data to use

void Ogre::TerrainQuadTreeNode::visitRenderables	(	Renderable::Visitor *	visitor,
		bool	debugRenderables = `false`
	)			`[protected]`

void Ogre::TerrainQuadTreeNode::writeDeltaVertex	(	bool	compress,
		uint16	x,
		uint16	y,
		float	delta,
		float	deltaThresh,
		float **	ppDelta
	)			`[protected]`

void Ogre::TerrainQuadTreeNode::writePosVertex	(	bool	compress,
		uint16	x,
		uint16	y,
		float	height,
		const Vector3 &	pos,
		float	uvScale,
		float **	ppPos
	)			`[protected]`