vtlib library: TVTerrain Class Reference

Inheritance diagram for TVTerrain:

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Public Member Functions
DTErr	Init (const vtElevationGrid *pGrid, float fZScale)
	initialization

Public Member Functions inherited from vtDynTerrainGeom
DTErr	BasicInit (const vtElevationGrid *pGrid)

virtual void	SetPolygonTarget (int iPolygonCount)

int	GetPolygonTarget () const

int	NumDrawnTriangles () const

Public Member Functions inherited from vtDynGeom
int	IsVisible (const FSphere &sphere) const

int	IsVisible (const FPoint3 &point0, const FPoint3 &point1, const FPoint3 &point2, const float fTolerance=0.0f) const

int	IsVisible (const FPoint3 &point, float radius)

bool	IsVisible (const FPoint3 &point) const

Public Member Functions inherited from vtGeode
void	AddMesh (vtMesh *pMesh, int iMatIdx)

void	RemoveMesh (vtMesh *pMesh)

void	AddTextMesh (vtTextMesh *pMesh, int iMatIdx)

uint	NumMeshes () const

vtMesh *	GetMesh (int i) const

vtTextMesh *	GetTextMesh (int i) const

Public Member Functions inherited from NodeExtension
void	SetEnabled (bool bOn)

bool	GetEnabled () const

void	SetCastShadow (bool b)
	Set this node to cast a shadow, if it is under a vtShadow node. Default is false.

bool	GetCastShadow ()
	Get whether this node casts a shadow.

void	GetBoundSphere (FSphere &sphere, bool bGlobal=false)
	Get the Bounding Sphere of the node.

Detailed Description

: The TVTerrain class implements the TopoVista algorithm for regular-grid terrain LOD.

: This algorithm requires that the input heightfield is a square regular grid, of any size. Storage requirements are around 14 bytes/vertex. The data is represented in memory by a binary tree of faces.

: The VTP implementation consists of an adaptation of the author's own source code, made to work in the vtDynTerrainGeom framework.

The algorithm is promising, but needs a lot of work:

So far i have extended the algorithm in the following ways:

Added full 6-plane view-volume culling (instead of the previously simple 2D culling). This required implementing some 3d triangle culling which was mysteriously absent from the computer graphics literature.