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#ifndef OSD_GL_VERTEX_BUFFER_H
#define OSD_GL_VERTEX_BUFFER_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"

namespace OpenSubdiv {
namespace OPENSUBDIV_VERSION {

///
/// \brief Concrete vertex buffer class for GLSL subvision and OpenGL drawing.
///
/// OsdGLVertexBuffer implements OsdGLVertexBufferInterface. An instance
/// of this buffer class can be passed to OsdGLComputeController
/// and OsdGLDrawController
///
class OsdGLVertexBuffer {
public:
    /// Creator. Returns NULL if error.
    static OsdGLVertexBuffer * Create(int numElements, int numVertices);

    /// Destructor.
    ~OsdGLVertexBuffer();

    /// This method is meant to be used in client code in order to provide coarse
    /// vertices data to Osd.
    void UpdateData(const float *src, int startVertex, int numVertices);

    /// Returns how many elements defined in this vertex buffer.
    int GetNumElements() const;

    /// Returns how many vertices allocated in this vertex buffer.
    int GetNumVertices() const;

    /// Returns the GL buffer object.
    GLuint BindVBO();

protected:
    /// Constructor.
    OsdGLVertexBuffer(int numElements, int numVertices);

    /// Allocates VBO for this buffer.
    /// Returns true if success.
    bool allocate();

private:
    int _numElements;
    int _numVertices;
    GLuint _vbo;
};

}  // end namespace OPENSUBDIV_VERSION
using namespace OPENSUBDIV_VERSION;

}  // end namespace OpenSubdiv

#endif  // OSD_GL_VERTEX_BUFFER_H