osd_tutorial_0.cpp
System Message: WARNING/2 (/build/opensubdiv/src/OpenSubdiv-3_6_1/build/documentation/osd_tutorial_0.rst, line 9)
Cannot analyze code. Pygments package not found.
.. code:: c++
//------------------------------------------------------------------------------
// Tutorial description:
//
// This tutorial demonstrates the manipulation of Osd Evaluator and
// BufferDescriptor.
//
#include <opensubdiv/far/topologyDescriptor.h>
#include <opensubdiv/far/stencilTableFactory.h>
#include <opensubdiv/osd/cpuEvaluator.h>
#include <opensubdiv/osd/cpuVertexBuffer.h>
#include <cstdio>
#include <cstring>
//------------------------------------------------------------------------------
// Cube geometry from catmark_cube.h
static float g_verts[24] = {-0.5f, -0.5f, 0.5f,
0.5f, -0.5f, 0.5f,
-0.5f, 0.5f, 0.5f,
0.5f, 0.5f, 0.5f,
-0.5f, 0.5f, -0.5f,
0.5f, 0.5f, -0.5f,
-0.5f, -0.5f, -0.5f,
0.5f, -0.5f, -0.5f};
static int g_nverts = 8,
g_nfaces = 6;
static int g_vertsperface[6] = { 4, 4, 4, 4, 4, 4 };
static int g_vertIndices[24] = { 0, 1, 3, 2,
2, 3, 5, 4,
4, 5, 7, 6,
6, 7, 1, 0,
1, 7, 5, 3,
6, 0, 2, 4 };
using namespace OpenSubdiv;
static Far::TopologyRefiner const * createTopologyRefiner(int maxlevel);
//------------------------------------------------------------------------------
int main(int, char **) {
int maxlevel=2,
nCoarseVerts=0,
nRefinedVerts=0;
//
// Setup phase
//
Far::StencilTable const * stencilTable = NULL;
{ // Setup Far::StencilTable
Far::TopologyRefiner const * refiner = createTopologyRefiner(maxlevel);
// Setup a factory to create FarStencilTable (for more details see
// Far tutorials)
Far::StencilTableFactory::Options options;
options.generateOffsets=true;
options.generateIntermediateLevels=false;
stencilTable = Far::StencilTableFactory::Create(*refiner, options);
nCoarseVerts = refiner->GetLevel(0).GetNumVertices();
nRefinedVerts = stencilTable->GetNumStencils();
// We are done with Far: cleanup table
delete refiner;
}
// Setup a buffer for vertex primvar data:
Osd::CpuVertexBuffer * vbuffer =
Osd::CpuVertexBuffer::Create(3, nCoarseVerts + nRefinedVerts);
//
// Execution phase (every frame)
//
{
// Pack the control vertex data at the start of the vertex buffer
// and update every time control data changes
vbuffer->UpdateData(g_verts, 0, nCoarseVerts);
Osd::BufferDescriptor srcDesc(0, 3, 3);
Osd::BufferDescriptor dstDesc(nCoarseVerts*3, 3, 3);
// Launch the computation
Osd::CpuEvaluator::EvalStencils(vbuffer, srcDesc,
vbuffer, dstDesc,
stencilTable);
}
{ // Visualization with Maya : print a MEL script that generates particles
// at the location of the refined vertices
printf("particle ");
float const * refinedVerts = vbuffer->BindCpuBuffer() + 3*nCoarseVerts;
for (int i=0; i<nRefinedVerts; ++i) {
float const * vert = refinedVerts + 3*i;
printf("-p %f %f %f\n", vert[0], vert[1], vert[2]);
}
printf("-c 1;\n");
}
delete stencilTable;
delete vbuffer;
}
//------------------------------------------------------------------------------
static Far::TopologyRefiner const *
createTopologyRefiner(int maxlevel) {
// Populate a topology descriptor with our raw data
typedef Far::TopologyDescriptor Descriptor;
Sdc::SchemeType type = OpenSubdiv::Sdc::SCHEME_CATMARK;
Sdc::Options options;
options.SetVtxBoundaryInterpolation(Sdc::Options::VTX_BOUNDARY_EDGE_ONLY);
Descriptor desc;
desc.numVertices = g_nverts;
desc.numFaces = g_nfaces;
desc.numVertsPerFace = g_vertsperface;
desc.vertIndicesPerFace = g_vertIndices;
// Instantiate a FarTopologyRefiner from the descriptor
Far::TopologyRefiner * refiner =
Far::TopologyRefinerFactory<Descriptor>::Create(desc,
Far::TopologyRefinerFactory<Descriptor>::Options(type, options));
// Uniformly refine the topology up to 'maxlevel'
refiner->RefineUniform(Far::TopologyRefiner::UniformOptions(maxlevel));
return refiner;
}
//------------------------------------------------------------------------------
Generated on: 2025-08-28 03:27 UTC.
