rcPolyMeshDetail Struct Reference

Contains triangle meshes that represent detailed height data associated with the polygons in its associated polygon mesh object. More...

#include <Recast.h>

Public Member Functions
	rcPolyMeshDetail ()

Public Attributes
unsigned int *	meshes
	The sub-mesh data. [Size: 4*nmeshes]. More...
float *	verts
	The mesh vertices. [Size: 3*nverts]. More...
unsigned char *	tris
	The mesh triangles. [Size: 4*ntris]. More...
int	nmeshes
	The number of sub-meshes defined by meshes. More...
int	nverts
	The number of vertices in verts. More...
int	ntris
	The number of triangles in tris. More...

Description

Contains triangle meshes that represent detailed height data associated with the polygons in its associated polygon mesh object.

The detail mesh is made up of triangle sub-meshes that provide extra height detail for each polygon in its assoicated polygon mesh.

The standard process for building a detail mesh is to allocate it using rcAllocPolyMeshDetail, then build it using rcBuildPolyMeshDetail.

See the individual field definitions for details realted to the structure the mesh.

See also

rcAllocPolyMeshDetail, rcFreePolyMeshDetail, rcBuildPolyMeshDetail, rcPolyMesh

Constructor & Destructor Documentation

rcPolyMeshDetail()

rcPolyMeshDetail::rcPolyMeshDetail

(

)

Member Data Documentation

meshes

rcPolyMeshDetail::meshes

The sub-mesh data. [Size: 4*nmeshes].

[(baseVertIndex, vertCount, baseTriIndex, triCount) * nmeshes]

Maximum number of vertices per sub-mesh: 127
Maximum number of triangles per sub-mesh: 255

The sub-meshes are stored in the same order as the polygons from the rcPolyMesh they represent. E.g. rcPolyMeshDetail sub-mesh 5 is associated with rcPolyMesh polygon 5.

Example of iterating the triangles in a sub-mesh.

// Where dmesh is a reference to a rcPolyMeshDetail object.
 
// Iterate the sub-meshes. (One for each source polygon.)
for (int i = 0; i < dmesh.nmeshes; ++i)
{
    const unsigned int* meshDef = &dmesh.meshes[i*4];
    const unsigned int baseVerts = meshDef[0];
    const unsigned int baseTri = meshDef[2];
    const int ntris = (int)meshDef[3];  
    
    const float* verts = &dmesh.verts[baseVerts*3];
    const unsigned char* tris = &dmesh.tris[baseTri*4];
 
    // Iterate the sub-mesh's triangles.
    for (int j = 0; j < ntris; ++j)
    {
        const float x = verts[tris[j*4+0]*3];
        const float y = verts[tris[j*4+1]*3];
        const float z = verts[tris[j*4+2]*3];
        // Do something with the vertex.
    }
}

nmeshes

int rcPolyMeshDetail::nmeshes

The number of sub-meshes defined by meshes.

ntris

int rcPolyMeshDetail::ntris

The number of triangles in tris.

nverts

int rcPolyMeshDetail::nverts

The number of vertices in verts.

tris

rcPolyMeshDetail::tris

The mesh triangles. [Size: 4*ntris].

[(vertIndexA, vertIndexB, vertIndexC, flags) * ntris]

The triangles are grouped by sub-mesh.

Vertex Indices

The vertex indices in the triangle array are local to the sub-mesh, not global. To translate into an global index in the vertices array, the values must be offset by the sub-mesh's base vertex index.

Example: If the baseVertexIndex for the sub-mesh is 5 and the triangle entry is (4, 8, 7, 0), then the actual indices for the vertices are (4 + 5, 8 + 5, 7 + 5).

Flags

The flags entry indicates which edges are internal and which are external to the sub-mesh. Internal edges connect to other triangles within the same sub-mesh. External edges represent portals to other sub-meshes or the null region.

Each flag is stored in a 2-bit position. Where position 0 is the lowest 2-bits and position 4 is the highest 2-bits:

Position 0: Edge AB (>> 0)
Position 1: Edge BC (>> 2)
Position 2: Edge CA (>> 4)
Position 4: Unused


Testing can be performed as follows:

if (((flags >> 2) & 0x3) != 0)
{
    // Edge BC is an external edge.
}

verts

rcPolyMeshDetail::verts

The mesh vertices. [Size: 3*nverts].

[(x, y, z) * nverts]

The vertices are grouped by sub-mesh and will contain duplicates since each sub-mesh is independently defined.

The first group of vertices for each sub-mesh are in the same order as the vertices for the sub-mesh's associated PolyMesh polygon. These vertices are followed by any additional detail vertices. So it the associated polygon has 5 vertices, the sub-mesh will have a minimum of 5 vertices and the first 5 vertices will be equivalent to the 5 polygon vertices.

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

• Recast.h
• Recast_api.txt
• Recast.cpp