SLGLVertexBuffer.h

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/**
 * \file      SLGLVertexBuffer.h
 * \brief     Wrapper class around OpenGL Vertex Buffer Objects (VBO)
 * \date      January 2016
 * \authors   Marcus Hudritsch
 * \copyright http://opensource.org/licenses/GPL-3.0
 * \remarks   Please use clangformat to format the code. See more code style on
 *            https://github.com/cpvrlab/SLProject4/wiki/SLProject-Coding-Style
*/
 
#ifndef SLGLVERTEXBUFFER_H
#define SLGLVERTEXBUFFER_H
 
#include <SLGLEnums.h>
#include <SLVec2.h>
#include <SLVec3.h>
#include <SLVec4.h>
 
//-----------------------------------------------------------------------------
//! Struct for vertex attribute information
struct SLGLAttribute
{
    SLGLAttributeType type;            //!< type of vertex attribute
    SLint             elementSize;     //!< size of attribute element (SLVec3f has 3)
    SLGLBufferType    dataType;        //! Data Type (BT_float, BT_ubyte,...)
    SLuint            offsetBytes;     //!< offset of the attribute data in the buffer
    SLuint            bufferSizeBytes; //!< size of the attribute part in the buffer
    void*             dataPointer;     //!< pointer to the attributes source data
    SLint             location;        //!< GLSL input variable location index
};
//-----------------------------------------------------------------------------
typedef vector<SLGLAttribute> SLVVertexAttrib;
//-----------------------------------------------------------------------------
 
//-----------------------------------------------------------------------------
//! SLGLVertexBuffer encapsulates an OpenGL buffer for vertex attributes
/*! SLGLVertexBuffer is only meant to be used within the SLGLVertexArray class.
Attributes can be either be in sequential order (first all positions, then all
normals, etc.) or interleaved (all attributes together for one vertex). See
SLGLVertexBuffer::generate for more information.\n
Vertex index buffer are not handled in this class. They are generated in
SLGLVertexArray.
*/
class SLGLVertexBuffer
{
public:
    SLGLVertexBuffer();
    ~SLGLVertexBuffer() { clear(); }
 
    //! Deletes all vertex array & vertex buffer objects
    void deleteGL();
 
    //! Calls deleteGL & clears the attributes
    void clear();
 
    //! Returns the vector index if a vertex attribute exists otherwise -1
    SLint attribIndex(SLGLAttributeType type);
 
    //! Updates a specific vertex attribute in the VBO
    void updateAttrib(SLGLAttributeType type,
                      SLint             elementSize,
                      void*             dataPointer);
 
    //! Updates a specific vertex attribute in the VBO
    void updateAttrib(SLGLAttributeType type,
                      SLVuint&          data) { updateAttrib(type, 1, (void*)&data[0]); }
 
    //! Updates a specific vertex attribute in the VBO
    void updateAttrib(SLGLAttributeType type,
                      SLVfloat&         data) { updateAttrib(type, 1, (void*)&data[0]); }
 
    //! Updates a specific vertex attribute in the VBO
    void updateAttrib(SLGLAttributeType type,
                      SLVVec2f&         data) { updateAttrib(type, 2, (void*)&data[0]); }
 
    //! Updates a specific vertex attribute in the VBO
    void updateAttrib(SLGLAttributeType type,
                      SLVVec3f&         data) { updateAttrib(type, 3, (void*)&data[0]); }
 
    //! Updates a specific vertex attribute in the VBO
    void updateAttrib(SLGLAttributeType type,
                      SLVVec4f&         data) { updateAttrib(type, 4, (void*)&data[0]); }
 
    //! Generates the VBO
    void generate(SLuint          numVertices,
                  SLGLBufferUsage usage             = BU_static,
                  SLbool          outputInterleaved = true);
 
    //! Binds & enables the vertex attribute for OpenGL < 3.0 and during VAO creation
    void bindAndEnableAttrib(SLuint divisor = 0) const;
 
    //! disables the vertex attribute for OpenGL < 3.0
    void disableAttrib();
 
    // Getters
    SLuint           id() const { return _id; }
    SLuint           size() const { return _id; }
    SLVVertexAttrib& attribs() { return _attribs; }
    SLbool           outputIsInterleaved() const { return _outputIsInterleaved; }
 
    // Setters
 
    // Some statistics
    static SLuint totalBufferCount; //! static total no. of buffers in use
    static SLuint totalBufferSize;  //! static total size of all buffers in bytes
 
    //! Returns the size of a buffer data type
    static SLuint sizeOfType(SLGLBufferType type);
 
protected:
    SLuint          _id;                //! OpenGL id of vertex buffer object
    SLuint          _numVertices;       //! NO. of vertices in array
    SLVVertexAttrib _attribs;           //! Vector of vertex attributes
    SLbool          _outputIsInterleaved; //! Flag if VBO should be generated interleaved
    SLbool          _inputIsInterleaved; //! Flag if VBO should be generated interleaved
    SLuint          _strideBytes;       //! Distance for interleaved attributes in bytes
    SLuint          _sizeBytes;         //! Total size of float VBO in bytes
    SLGLBufferUsage _usage;             //! buffer usage (static, dynamic or stream)
};
//-----------------------------------------------------------------------------
 
#endif