vtGeomFactory Class Reference

Public Member Functions
	vtGeomFactory (vtGeode *pGeode, vtMesh::PrimType ePrimType, int iVertType, int iMaxVertsPerMesh, int iMatIndex, int iExpectedVerts=-1)
	vtGeomFactory (vtMesh *pMesh)
void	PrimStart ()
void	AddVertex (const FPoint3 &p)
void	PrimEnd ()
float	AddSurfaceLineToMesh (vtHeightField3d *pHF, const DLine2 &line, float fSpacing, float fOffset, bool bInterp=true, bool bCurve=false, bool bTrue=false)

Detailed Description

The vtGeomFactory class makes it easy to create geometry with a lot of vertices. You simply provide vertices, and it will create as many geometries as necessary to contain them all.

Example:

This example produces a line strip with 10000 vertices. The factory is told to limit the number of vertices in a single primitive to 3000, so it will automatically produce four geometries with 3000, 3000, 3000, and 1000 vertices each. The geometries are automatically added to the indicated geode.

{
   vtGeode *pLineGeom = new vtGeode;
   vtGeomFactory mf(pLineGeom, osg::PrimitiveSet::LINE_STRIP, 0, 3000, 1);
   mf.PrimStart();
   for (int i = 0; i < 10000; i++)
       mf.AddVertex(FPoint3(i,i,i));
   mf.PrimEnd();
}

Constructor & Destructor Documentation

vtGeomFactory::vtGeomFactory	(	vtGeode *	pGeode,
		vtMesh::PrimType	ePrimType,
		int	iVertType,
		int	iMaxVertsPerMesh,
		int	iMatIndex,
		int	iExpectedVerts = -1
	)

Constructor.

Parameters

pGeode	The geometry node which will receive the mesh object(s) that this factory will produce.
ePrimType	The type of mesh to produce.
iVertType	The vertex attributes for the meshes to produce.
iMaxVertsPerMesh	The largest number of vertices to allow in a single mesh. When this number is exceeded, the current mesh will be finished and another mesh begun.
iMatIndex	The material index of the mesh when it is added to the geometry node.
iExpectedVerts	If you know how many vertices will be mesh ahead of time, you can save a little time and memory by passing the number.

vtGeomFactory::vtGeomFactory

(

vtMesh *

pMesh

)

Alternate, simpler constructor.

Parameters

pMesh

The mesh which will receive all the vertices that this factory produces.

Member Function Documentation

float vtGeomFactory::AddSurfaceLineToMesh	(	vtHeightField3d *	pHF,
		const DLine2 &	line,
		float	fSpacing,
		float	fOffset,
		bool	bInterp = true,
		bool	bCurve = false,
		bool	bTrue = false
	)

Create geometry for a 2D line by draping the points on a heightfield.

Parameters

pHF	The heightfield to drape on.
line	The 2D line to drape, in Earth coordinates.
fSpacing	The approximate spacing of the surface tessellation, used to decide how finely to tessellate the line.
fOffset	An offset to elevate each point in the resulting geometry, useful for keeping it visibly above the ground.
bInterp	True to interpolate between the vertices of the input line. This is generally desirable when the ground is much more finely spaced than the input line.
bCurve	True to interpret the vertices of the input line as control points of a curve. The created geometry will consist of a draped line which passes through the control points.
bTrue	True to use the true elevation of the terrain, ignoring whatever scale factor is being used to exaggerate elevation for display.

Returns

The approximate length of the resulting 3D line mesh.

Example:

DLine2 line = ...;
vtTerrain *pTerr = ...;
vtGeode *pLineGeom = new vtGeode;
pTerr->AddNode(pLineGeom);
vtGeomFactory mf(pLineGeom, osg::PrimitiveSet::LINE_STRIP, 0, 30000, 1);
float length = mf.AddSurfaceLineToMesh(pTerr->GetHeightfield(), dline, 1, 10, true);

void vtGeomFactory::AddVertex

(

const FPoint3 &

p

)

Tell the factory to add a vertex to the current primitive.

void vtGeomFactory::PrimEnd

(

)

Tell the factory to end a primitive.

void vtGeomFactory::PrimStart

(

)

Tell the factory to start a primitive.