OpenSubdiv/opensubdiv/osd/glslTransformFeedbackComputeContext.h

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#ifndef OSD_GLSL_TRANSFORM_FEEDBACK_COMPUTE_CONTEXT_H
#define OSD_GLSL_TRANSFORM_FEEDBACK_COMPUTE_CONTEXT_H

#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/gl.h>
#endif

#include "../version.h"

#include "../far/vertexEditTables.h"
#include "../osd/vertex.h"
#include "../osd/nonCopyable.h"

#include <vector>

namespace OpenSubdiv {
namespace OPENSUBDIV_VERSION {

class OsdGLSLTransformFeedbackKernelBundle;

// ----------------------------------------------------------------------------

class OsdGLSLTransformFeedbackTable : OsdNonCopyable<OsdGLSLTransformFeedbackTable> {
public:
    template<typename T>
    OsdGLSLTransformFeedbackTable(const std::vector<T> &table, GLenum type) {
        createTextureBuffer(table.size() * sizeof(unsigned int), &table[0], type);
    }

    virtual ~OsdGLSLTransformFeedbackTable();

    GLuint GetTexture() const;

private:
    void createTextureBuffer(size_t size, const void *ptr, GLenum type);

    GLuint _buffer, _texture;
};

// ----------------------------------------------------------------------------

class OsdGLSLTransformFeedbackHEditTable : OsdNonCopyable<OsdGLSLTransformFeedbackHEditTable> {
public:
    OsdGLSLTransformFeedbackHEditTable(const FarVertexEditTables<OsdVertex>::
                      VertexEditBatch &batch);

    virtual ~OsdGLSLTransformFeedbackHEditTable();

    const OsdGLSLTransformFeedbackTable * GetPrimvarIndices() const;

    const OsdGLSLTransformFeedbackTable * GetEditValues() const;

    int GetOperation() const;

    int GetPrimvarOffset() const;

    int GetPrimvarWidth() const;

private:
    OsdGLSLTransformFeedbackTable *_primvarIndicesTable;
    OsdGLSLTransformFeedbackTable *_editValuesTable;

    int _operation;
    int _primvarOffset;
    int _primvarWidth;
};

// ----------------------------------------------------------------------------

class OsdGLSLTransformFeedbackComputeContext {
public:
    static OsdGLSLTransformFeedbackComputeContext * Create(FarMesh<OsdVertex> *farmesh);

    virtual ~OsdGLSLTransformFeedbackComputeContext();

    template<class VERTEX_BUFFER, class VARYING_BUFFER>
    void Bind(VERTEX_BUFFER *vertex, VARYING_BUFFER *varying) {

        _currentVertexBuffer = vertex ? vertex->BindVBO() : 0;
        _currentVaryingBuffer = varying ? varying->BindVBO() : 0;

        _numVertexElements = vertex ? vertex->GetNumElements() : 0;
        _numVaryingElements = varying ? varying->GetNumElements() : 0;

        bindTextures();
    }

    void Unbind() {
        _currentVertexBuffer = 0;
        _currentVaryingBuffer = 0;
        unbindTextures();
    }

    const OsdGLSLTransformFeedbackTable * GetTable(int tableIndex) const;

    int GetNumEditTables() const;

    const OsdGLSLTransformFeedbackHEditTable * GetEditTable(int tableIndex) const;

    GLuint GetCurrentVertexBuffer() const;

    GLuint GetCurrentVaryingBuffer() const;

    int GetNumCurrentVertexElements() const;

    int GetNumCurrentVaryingElements() const;

    OsdGLSLTransformFeedbackKernelBundle * GetKernelBundle() const;

    void SetKernelBundle(OsdGLSLTransformFeedbackKernelBundle *kernelBundle);

    void BindEditTextures(int editIndex);

    void UnbindEditTextures();

protected:
    explicit OsdGLSLTransformFeedbackComputeContext(FarMesh<OsdVertex> *farMesh);

    void bindTexture(GLuint sampler, GLuint texture, int unit);

    void unbindTexture(GLuint unit);

    void bindTextures();

    void unbindTextures();

private:
    std::vector<OsdGLSLTransformFeedbackTable*> _tables;
    std::vector<OsdGLSLTransformFeedbackHEditTable*> _editTables;

    GLuint _vertexTexture;
    GLuint _varyingTexture;

    int _numVertexElements;
    int _numVaryingElements;

    GLuint _currentVertexBuffer, _currentVaryingBuffer;

    OsdGLSLTransformFeedbackKernelBundle * _kernelBundle;
};

}  // end namespace OPENSUBDIV_VERSION
using namespace OPENSUBDIV_VERSION;

}  // end namespace OpenSubdiv

#endif  // OSD_GLSL_TRANSFORM_FEEDBACK_COMPUTE_CONTEXT_H