OpenSubdiv/opensubdiv/osd/glDrawContext.cpp

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#if defined(__APPLE__)
    #include "TargetConditionals.h"
    #if TARGET_OS_IPHONE or TARGET_IPHONE_SIMULATOR
        #include <OpenGLES/ES2/gl.h>
    #else
        #include <OpenGL/gl3.h>
    #endif
#elif defined(ANDROID)
    #include <GLES2/gl2.h>
#else
    #if defined(_WIN32)
        #include <windows.h>
    #endif
    #include <GL/glew.h>
#endif

#include "../far/dispatcher.h"
#include "../far/loopSubdivisionTables.h"
#include "../osd/glDrawRegistry.h"
#include "../osd/glDrawContext.h"

namespace OpenSubdiv {
namespace OPENSUBDIV_VERSION {

OsdGLDrawContext::OsdGLDrawContext() :
    patchIndexBuffer(0), ptexCoordinateTextureBuffer(0), fvarDataTextureBuffer(0),
    vertexTextureBuffer(0), vertexValenceTextureBuffer(0), quadOffsetTextureBuffer(0)
{
}

OsdGLDrawContext::~OsdGLDrawContext()
{
    glDeleteBuffers(1, &patchIndexBuffer);
    glDeleteTextures(1, &vertexTextureBuffer);
    glDeleteTextures(1, &vertexValenceTextureBuffer);
    glDeleteTextures(1, &quadOffsetTextureBuffer);
    glDeleteTextures(1, &ptexCoordinateTextureBuffer);
    glDeleteTextures(1, &fvarDataTextureBuffer);
}

bool
OsdGLDrawContext::SupportsAdaptiveTessellation()
{
// Compile-time check of GL version
#if (defined(GL_ARB_tessellation_shader) or defined(GL_VERSION_4_0)) and defined(GLEW_VERSION_4_0)
    // Run-time check of GL version with GLEW
    if (GLEW_VERSION_4_0) {
        return true;
    }
#endif
    return false;
}

bool
OsdGLDrawContext::allocate(FarMesh<OsdVertex> *farMesh,
                           GLuint vbo,
                           int numElements,
                           bool requireFVarData)
{
    FarPatchTables const * patchTables = farMesh->GetPatchTables();

    if (not patchTables) {
        // uniform patches
        _isAdaptive = false;

        // XXX: farmesh should have FarDensePatchTable for dense mesh indices.
        //      instead of GetFaceVertices().
        const FarSubdivisionTables<OsdVertex> *tables = farMesh->GetSubdivisionTables();
        int level = tables->GetMaxLevel();
        const std::vector<int> &indices = farMesh->GetFaceVertices(level-1);

        int numIndices = (int)indices.size();

        // Allocate and fill index buffer.
        glGenBuffers(1, &patchIndexBuffer);
        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, patchIndexBuffer);
        glBufferData(GL_ELEMENT_ARRAY_BUFFER,
                     numIndices * sizeof(unsigned int), &(indices[0]), GL_STATIC_DRAW);

#if defined(GL_ES_VERSION_2_0)
        // OpenGLES 2 supports only triangle topologies for filled
        // primitives i.e. not QUADS or PATCHES or LINES_ADJACENCY
        // For the convenience of clients build build a triangles
        // index buffer by splitting quads.
        int numQuads = indices.size() / 4;
        int numTrisIndices = numQuads * 6;

        std::vector<short> trisIndices;
        trisIndices.reserve(numTrisIndices);
        for (int i=0; i<numQuads; ++i) {
            const int * quad = &indices[i*4];
            trisIndices.push_back(short(quad[0]));
            trisIndices.push_back(short(quad[1]));
            trisIndices.push_back(short(quad[2]));

            trisIndices.push_back(short(quad[2]));
            trisIndices.push_back(short(quad[3]));
            trisIndices.push_back(short(quad[0]));
        }

        // Allocate and fill triangles index buffer.
        glGenBuffers(1, &patchTrianglesIndexBuffer);
        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, patchTrianglesIndexBuffer);
        glBufferData(GL_ELEMENT_ARRAY_BUFFER,
                     numTrisIndices * sizeof(short), &(trisIndices[0]), GL_STATIC_DRAW);
#endif

/*
        OsdPatchArray array;
        array.desc.type = kNonPatch;
        array.desc.loop = dynamic_cast<const FarLoopSubdivisionTables<OsdVertex>*>(tables) != NULL;
        array.firstIndex = 0;
        array.numIndices = numIndices;

        patchArrays.push_back(array);
*/

        // Allocate ptex coordinate buffer
#if defined(GL_ARB_texture_buffer_object) || defined(GL_VERSION_3_1)
        GLuint ptexCoordinateBuffer = 0;
        glGenTextures(1, &ptexCoordinateTextureBuffer);
        glGenBuffers(1, &ptexCoordinateBuffer);
        glBindBuffer(GL_TEXTURE_BUFFER, ptexCoordinateBuffer);

        const std::vector<FarPtexCoord> &ptexCoordinates =
            farMesh->GetPtexCoordinates(level-1);
        int size = (int)ptexCoordinates.size() * sizeof(FarPtexCoord);

        glBufferData(GL_TEXTURE_BUFFER, size, &(ptexCoordinates[0]), GL_STATIC_DRAW);
        
        glBindTexture(GL_TEXTURE_BUFFER, ptexCoordinateTextureBuffer);
        glTexBuffer(GL_TEXTURE_BUFFER, GL_RG32I, ptexCoordinateBuffer);
        glBindTexture(GL_TEXTURE_BUFFER, 0);
        glDeleteBuffers(1, &ptexCoordinateBuffer);

#endif

        // Allocate fvar data buffer if requested (for non-adaptive)
        if (requireFVarData) {
#if defined(GL_ARB_texture_buffer_object) || defined(GL_VERSION_3_1)
            GLuint fvarDataBuffer = 0;
            glGenTextures(1, &fvarDataTextureBuffer);
            glGenBuffers(1, &fvarDataBuffer);
            glBindBuffer(GL_TEXTURE_BUFFER, fvarDataBuffer);

            const std::vector<float> &fvarData = farMesh->GetFVarData(level-1);
            int size = (int)fvarData.size() * sizeof(float);

            glBufferData(GL_TEXTURE_BUFFER, size, &(fvarData[0]), GL_STATIC_DRAW);

            glBindTexture(GL_TEXTURE_BUFFER, fvarDataTextureBuffer);
            glTexBuffer(GL_TEXTURE_BUFFER, GL_R32F, fvarDataBuffer);
            glDeleteBuffers(1, &fvarDataBuffer);
            glBindTexture(GL_TEXTURE_BUFFER, 0);
#endif
        }

        return true;
    }

    // adaptive patches
    _isAdaptive = true;

    int maxValence = patchTables->GetMaxValence();

    // create patch arrays for drawing (while duplicating subpatches for transition patch arrays)
    {
        static int subPatchCounts[] = { 1, 3, 4, 4, 4, 2 }; // number of subpatches for patterns

        FarPatchTables::PatchArrayVector const & srcPatchArrays = patchTables->GetAllPatchArrays();

        int numTotalPatchArrays = 0;
        for (int i = 0; i < (int)srcPatchArrays.size(); ++i) {
            FarPatchTables::TransitionPattern pattern = srcPatchArrays[i].GetDescriptor().GetPattern();
            numTotalPatchArrays += subPatchCounts[(int)pattern];
        }

        // allocate drawing patch arrays
        patchArrays.reserve(numTotalPatchArrays);
        for (int i = 0; i < (int)srcPatchArrays.size(); ++i) {
            FarPatchTables::TransitionPattern pattern = srcPatchArrays[i].GetDescriptor().GetPattern();
            int numSubPatches = subPatchCounts[(int)pattern];

            FarPatchTables::PatchArray const &parray = srcPatchArrays[i];
            FarPatchTables::Descriptor srcDesc = parray.GetDescriptor();

            for (int j = 0; j < numSubPatches; ++j) {
                FarPatchTables::Descriptor desc(srcDesc.GetType(),
                                                srcDesc.GetPattern(),
                                                srcDesc.GetRotation(),
                                                maxValence,
                                                j,
                                                numElements);

                patchArrays.push_back(FarPatchTables::PatchArray(desc, parray.GetVertIndex(),
                                                                 parray.GetPatchIndex(),
                                                                 parray.GetNumPatches(),
                                                                 parray.GetQuadOffsetIndex()));
            }
        }
    }

    FarPatchTables::PTable const & ptables = patchTables->GetPatchTable();

    // Allocate and fill index buffer.
    glGenBuffers(1, &patchIndexBuffer);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, patchIndexBuffer);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER,
                 ptables.size() * sizeof(unsigned int), &ptables[0], GL_STATIC_DRAW);

    FarPatchTables::PtexCoordinateTable const & ptexCoordTables = patchTables->GetPtexCoordinatesTable();

    // Allocate ptex coordinate buffer if requested
    GLuint ptexCoordinateBuffer = 0;
#if defined(GL_ARB_texture_buffer_object) || defined(GL_VERSION_3_1)
    glGenTextures(1, &ptexCoordinateTextureBuffer);
    glGenBuffers(1, &ptexCoordinateBuffer);
    glBindBuffer(GL_ARRAY_BUFFER, ptexCoordinateBuffer);
    glBufferData(GL_ARRAY_BUFFER,
                 ptexCoordTables.size() * sizeof(FarPtexCoord), &ptexCoordTables[0], GL_STATIC_DRAW);
#endif

    // Allocate fvar data buffer if requested
    GLuint fvarDataBuffer = 0;
    if (requireFVarData) {
#if defined(GL_ARB_texture_buffer_object) || defined(GL_VERSION_3_1)
        FarPatchTables::FVarDataTable const & fvarTables = patchTables->GetFVarDataTable();

        glGenTextures(1, &fvarDataTextureBuffer);
        glGenBuffers(1, &fvarDataBuffer);
        glBindBuffer(GL_UNIFORM_BUFFER, fvarDataBuffer);
        glBufferData(GL_UNIFORM_BUFFER,
                     fvarTables.size() * sizeof(float), &fvarTables[0], GL_STATIC_DRAW);
#endif
    }

#if defined(GL_ARB_texture_buffer_object) || defined(GL_VERSION_3_1)

    // finalize ptex coordinate texture buffer
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glBindTexture(GL_TEXTURE_BUFFER, ptexCoordinateTextureBuffer);
    glTexBuffer(GL_TEXTURE_BUFFER, GL_RG32I, ptexCoordinateBuffer);
    glDeleteBuffers(1, &ptexCoordinateBuffer);

    // finalize fvar data texture buffer
    glBindBuffer(GL_UNIFORM_BUFFER, 0);
    if (requireFVarData) {
        glBindTexture(GL_TEXTURE_BUFFER, fvarDataTextureBuffer);
        glTexBuffer(GL_TEXTURE_BUFFER, GL_R32F, fvarDataBuffer);
        glDeleteBuffers(1, &fvarDataBuffer);
    }
#endif

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
#if defined(GL_ARB_texture_buffer_object) || defined(GL_VERSION_3_1)
    glBindBuffer(GL_TEXTURE_BUFFER, 0);
#endif

    // allocate and initialize additional buffer data
    FarPatchTables::VertexValenceTable const &
        valenceTable = patchTables->GetVertexValenceTable();

    if (not valenceTable.empty()) {
#if defined(GL_ARB_texture_buffer_object) || defined(GL_VERSION_3_1)
        GLuint buffer = 0;
        glGenBuffers(1, &buffer);
        glBindBuffer(GL_TEXTURE_BUFFER, buffer);
        glBufferData(GL_TEXTURE_BUFFER,
                valenceTable.size() * sizeof(unsigned int),
                &valenceTable[0], GL_STATIC_DRAW);

        glGenTextures(1, &vertexValenceTextureBuffer);
        glBindTexture(GL_TEXTURE_BUFFER, vertexValenceTextureBuffer);
        glTexBuffer(GL_TEXTURE_BUFFER, GL_R32I, buffer);
        glDeleteBuffers(1, &buffer);

        glGenTextures(1, &vertexTextureBuffer);
        glBindTexture(GL_TEXTURE_BUFFER, vertexTextureBuffer);
        glTexBuffer(GL_TEXTURE_BUFFER, GL_R32F, vbo);

        glBindBuffer(GL_TEXTURE_BUFFER, 0);
#endif
    }

    FarPatchTables::QuadOffsetTable const &
        quadOffsetTable = patchTables->GetQuadOffsetTable();

    if (not quadOffsetTable.empty()) {
#if defined(GL_ARB_texture_buffer_object) || defined(GL_VERSION_3_1)
        GLuint buffer = 0;
        glGenBuffers(1, &buffer);
        glBindBuffer(GL_TEXTURE_BUFFER, buffer);
        glBufferData(GL_TEXTURE_BUFFER,
                quadOffsetTable.size() * sizeof(unsigned int),
                &quadOffsetTable[0], GL_STATIC_DRAW);

        glGenTextures(1, &quadOffsetTextureBuffer);
        glBindTexture(GL_TEXTURE_BUFFER, quadOffsetTextureBuffer);
        glTexBuffer(GL_TEXTURE_BUFFER, GL_R32I, buffer);
        glDeleteBuffers(1, &buffer);

        glBindBuffer(GL_TEXTURE_BUFFER, 0);
#endif
    }

    return true;
}

} // end namespace OPENSUBDIV_VERSION
} // end namespace OpenSubdiv