/*
 *  VBOMesh.h
 *  OpenGL SuperBible
 *
 *  Copyright 2007 Richard S. Wright Jr.. All rights reserved.
 *  This class allows you to simply add triangles as if this class were a 
 *  container. The AddTriangle() function searches the current list of triangles
 *  and determines if the vertex/normal/texcoord is a duplicate. If so, it addes
 *  an entry to the index array instead of the list of vertices.
 *  When finished, call EndMesh() to free up extra unneeded memory that is reserved
 *  as workspace when you call BeginMesh().
 *
 *  This class can easily be extended to contain other vertex attributes, and to 
 *  save itself and load itself from disk (thus forming the beginnings of a custom
 *  model file format).
 *
 *  Very similiar to CTriangleMesh, except the final arrays are stored in Vertex buffer objects
 *  Before anybody flames me, bear in mind this is not a book on object oriented programming, 
 *  and I'm trying to be nice to the C people ;-)
 *  Yes, I know all about inheritance, and it's all good....
 */
 
#include "gltools.h"
#include "math3d.h"

#define VERTEX_DATA     0
#define NORMAL_DATA     1
#define TEXTURE_DATA    2
#define INDEX_DATA      3

class CVBOMesh
{
    public:
        CVBOMesh(void);
        ~CVBOMesh(void);
        
        // Use these three functions to add triangles
        void BeginMesh(GLuint nMaxVerts);
        void AddTriangle(M3DVector3f verts[3], M3DVector3f vNorms[3], M3DVector2f vTexCoords[3]);
        void EndMesh(void);

        // Useful for statistics
        inline GLuint GetIndexCount(void) { return nNumIndexes; }
        inline GLuint GetVertexCount(void) { return nNumVerts; }
        
        // In place scale of the vertices
        void Scale(GLfloat fScaleValue);
        
        // Draw - make sure you call glEnableClientState for these arrays
        void Draw(void);
        
    protected:
        GLushort  *pIndexes;          // Array of indexes
        M3DVector3f *pVerts;        // Array of vertices
        M3DVector3f *pNorms;        // Array of normals
        M3DVector2f *pTexCoords;    // Array of texture coordinates
        
        GLuint nMaxIndexes;         // Maximum workspace
        GLuint nNumIndexes;         // Number of indexes currently used
        GLuint nNumVerts;           // Number of vertices actually used
        
        GLuint bufferObjects[4];
};