/**
 * $Id$
 *
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version. The Blender
 * Foundation also sells licenses for use in proprietary software under
 * the Blender License.  See http://www.blender.org/BL/ for information
 * about this.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2005 Blender Foundation.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): Brecht Van Lommel.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#include <limits.h>
#include <stddef.h>
#include <string.h>

#include "GL/glew.h"

#include "MEM_guardedalloc.h"

#include "BLI_ghash.h"
#include "BLI_math.h"
#include "BLI_threads.h"

#include "DNA_meshdata_types.h"

#include "BKE_DerivedMesh.h"
#include "BKE_utildefines.h"

#include "DNA_userdef_types.h"

#include "GPU_buffers.h"

#define GPU_BUFFER_VERTEX_STATE 1
#define GPU_BUFFER_NORMAL_STATE 2
#define GPU_BUFFER_TEXCOORD_STATE 4
#define GPU_BUFFER_COLOR_STATE 8
#define GPU_BUFFER_ELEMENT_STATE 16

#define MAX_GPU_ATTRIB_DATA 32

/* -1 - undefined, 0 - vertex arrays, 1 - VBOs */
int useVBOs = -1;
GPUBufferPool *globalPool = 0;
int GLStates = 0;
GPUAttrib attribData[MAX_GPU_ATTRIB_DATA] = { { -1, 0, 0 } };

GPUBufferPool *GPU_buffer_pool_new()
{
	GPUBufferPool *pool;

	DEBUG_VBO("GPU_buffer_pool_new\n");

	if( useVBOs < 0 ) {
		if( GL_ARB_vertex_buffer_object ) {
			DEBUG_VBO( "Vertex Buffer Objects supported.\n" );
			useVBOs = 1;
		}
		else {
			DEBUG_VBO( "Vertex Buffer Objects NOT supported.\n" );
			useVBOs = 0;
		}
	}

	pool = MEM_callocN(sizeof(GPUBufferPool), "GPU_buffer_pool_new");
	pool->maxsize = MAX_FREE_GPU_BUFFERS;
	pool->buffers = MEM_callocN(sizeof(GPUBuffer*)*pool->maxsize, "GPU_buffer_pool_new buffers");

	return pool;
}

void GPU_buffer_pool_remove( int index, GPUBufferPool *pool )
{
	int i;

	if( index >= pool->size || index < 0 ) {
		ERROR_VBO("Wrong index, out of bounds in call to GPU_buffer_pool_remove");
		return;
	}
	DEBUG_VBO("GPU_buffer_pool_remove\n");

	for( i = index; i < pool->size-1; i++ ) {
		pool->buffers[i] = pool->buffers[i+1];
	}
	if( pool->size > 0 )
		pool->buffers[pool->size-1] = 0;

	pool->size--;
}

void GPU_buffer_pool_delete_last( GPUBufferPool *pool )
{
	int last;

	DEBUG_VBO("GPU_buffer_pool_delete_last\n");

	if( pool->size <= 0 )
		return;

	last = pool->size-1;

	if( pool->buffers[last] != 0 ) {
		if( useVBOs ) {
			glDeleteBuffersARB(1,&pool->buffers[last]->id);
			MEM_freeN( pool->buffers[last] );
		}
		else {
			MEM_freeN( pool->buffers[last]->pointer );
			MEM_freeN( pool->buffers[last] );
		}
		pool->buffers[last] = 0;
	} else {
		DEBUG_VBO("Why are we accessing a null buffer?\n");
	}
	pool->size--;
}

void GPU_buffer_pool_free(GPUBufferPool *pool)
{
	DEBUG_VBO("GPU_buffer_pool_free\n");

	if( pool == 0 )
		pool = globalPool;
	if( pool == 0 )
		return;
	
	while( pool->size )
		GPU_buffer_pool_delete_last(pool);

	MEM_freeN(pool->buffers);
	MEM_freeN(pool);
}

void GPU_buffer_pool_free_unused(GPUBufferPool *pool)
{
	DEBUG_VBO("GPU_buffer_pool_free_unused\n");

	if( pool == 0 )
		pool = globalPool;
	if( pool == 0 )
		return;
	
	while( pool->size > MAX_FREE_GPU_BUFFERS )
		GPU_buffer_pool_delete_last(pool);
}

GPUBuffer *GPU_buffer_alloc( int size, GPUBufferPool *pool )
{
	char buffer[60];
	int i;
	int cursize;
	GPUBuffer *allocated;
	int bestfit = -1;

	DEBUG_VBO("GPU_buffer_alloc\n");

	if( pool == 0 ) {
		if( globalPool == 0 )
			globalPool = GPU_buffer_pool_new();
		pool = globalPool;
	}

	for( i = 0; i < pool->size; i++ ) {
		cursize = pool->buffers[i]->size;
		if( cursize == size ) {
			allocated = pool->buffers[i];
			GPU_buffer_pool_remove(i,pool);
			DEBUG_VBO("free buffer of exact size found\n");
			return allocated;
		}
		/* smaller buffers won't fit data and buffers at least twice as big are a waste of memory */
		else if( cursize > size && size > cursize/2 ) {
			/* is it closer to the required size than the last appropriate buffer found. try to save memory */
			if( bestfit == -1 || pool->buffers[bestfit]->size > cursize ) {
				bestfit = i;
			}
		}
	}
	if( bestfit == -1 ) {
		DEBUG_VBO("allocating a new buffer\n");

		allocated = MEM_mallocN(sizeof(GPUBuffer), "GPU_buffer_alloc");
		allocated->size = size;
		if( useVBOs == 1 ) {
			glGenBuffersARB( 1, &allocated->id );
			glBindBufferARB( GL_ARRAY_BUFFER_ARB, allocated->id );
			glBufferDataARB( GL_ARRAY_BUFFER_ARB, size, 0, GL_STATIC_DRAW_ARB );
			glBindBufferARB( GL_ARRAY_BUFFER_ARB, 0 );
		}
		else {
			allocated->pointer = MEM_mallocN(size, "GPU_buffer_alloc_vertexarray");
			while( allocated->pointer == 0 && pool->size > 0 ) {
				GPU_buffer_pool_delete_last(pool);
				allocated->pointer = MEM_mallocN(size, "GPU_buffer_alloc_vertexarray");
			}
			if( allocated->pointer == 0 && pool->size == 0 ) {
				return 0;
			}
		}
	}
	else {
		sprintf(buffer,"free buffer found. Wasted %d bytes\n", pool->buffers[bestfit]->size-size);
		DEBUG_VBO(buffer);

		allocated = pool->buffers[bestfit];
		GPU_buffer_pool_remove(bestfit,pool);
	}
	return allocated;
}

void GPU_buffer_free( GPUBuffer *buffer, GPUBufferPool *pool )
{
	int i;

	DEBUG_VBO("GPU_buffer_free\n");

	if( buffer == 0 )
		return;
	if( pool == 0 )
		pool = globalPool;
	if( pool == 0 )
		globalPool = GPU_buffer_pool_new();

	/* free the last used buffer in the queue if no more space, but only
	   if we are in the main thread. for e.g. rendering or baking it can
	   happen that we are in other thread and can't call OpenGL, in that
	   case cleanup will be done GPU_buffer_pool_free_unused */
	if( BLI_thread_is_main() ) {
		while( pool->size >= MAX_FREE_GPU_BUFFERS )
			GPU_buffer_pool_delete_last( pool );
	}
	else {
		if( pool->maxsize == pool->size ) {
			pool->maxsize += MAX_FREE_GPU_BUFFERS;
			pool->buffers = MEM_reallocN(pool->buffers, sizeof(GPUBuffer*)*pool->maxsize);
		}
	}

	for( i =pool->size; i > 0; i-- ) {
		pool->buffers[i] = pool->buffers[i-1];
	}
	pool->buffers[0] = buffer;
	pool->size++;
}

GPUDrawObject *GPU_drawobject_new( DerivedMesh *dm )
{
	GPUDrawObject *object;
	MVert *mvert;
	MFace *mface;
	int numverts[32768];	/* material number is an 16-bit short so there's at most 32768 materials */
	int redir[32768];		/* material number is an 16-bit short so there's at most 32768 materials */
	int *index;
	int i;
	int curmat, curverts, numfaces;

	DEBUG_VBO("GPU_drawobject_new\n");

	object = MEM_callocN(sizeof(GPUDrawObject),"GPU_drawobject_new_object");
	object->nindices = dm->getNumVerts(dm);
	object->indices = MEM_mallocN(sizeof(IndexLink)*object->nindices, "GPU_drawobject_new_indices");
	object->nedges = dm->getNumEdges(dm);

	for( i = 0; i < object->nindices; i++ ) {
		object->indices[i].element = -1;
		object->indices[i].next = 0;
	}
	/*object->legacy = 1;*/
	memset(numverts,0,sizeof(int)*32768);

	mvert = dm->getVertArray(dm);
	mface = dm->getFaceArray(dm);

	numfaces= dm->getNumFaces(dm);
	for( i=0; i < numfaces; i++ ) {
		if( mface[i].v4 )
			numverts[mface[i].mat_nr+16383] += 6;	/* split every quad into two triangles */
		else
			numverts[mface[i].mat_nr+16383] += 3;
	}

	for( i = 0; i < 32768; i++ ) {
		if( numverts[i] > 0 ) {
			object->nmaterials++;
			object->nelements += numverts[i];
		}
	}
	object->materials = MEM_mallocN(sizeof(GPUBufferMaterial)*object->nmaterials,"GPU_drawobject_new_materials");
	index = MEM_mallocN(sizeof(int)*object->nmaterials,"GPU_drawobject_new_index");

	curmat = curverts = 0;
	for( i = 0; i < 32768; i++ ) {
		if( numverts[i] > 0 ) {
			object->materials[curmat].mat_nr = i-16383;
			object->materials[curmat].start = curverts;
			index[curmat] = curverts/3;
			object->materials[curmat].end = curverts+numverts[i];
			curverts += numverts[i];
			curmat++;
		}
	}
	object->faceRemap = MEM_mallocN(sizeof(int)*object->nelements/3,"GPU_drawobject_new_faceRemap");
	for( i = 0; i < object->nmaterials; i++ ) {
		redir[object->materials[i].mat_nr+16383] = i;	/* material number -> material index */
	}

	object->indexMem = MEM_callocN(sizeof(IndexLink)*object->nelements,"GPU_drawobject_new_indexMem");
	object->indexMemUsage = 0;

#define ADDLINK( INDEX, ACTUAL ) \
		if( object->indices[INDEX].element == -1 ) { \
			object->indices[INDEX].element = ACTUAL; \
		} else { \
			IndexLink *lnk = &object->indices[INDEX]; \
			while( lnk->next != 0 ) lnk = lnk->next; \
			lnk->next = &object->indexMem[object->indexMemUsage]; \
			lnk->next->element = ACTUAL; \
			object->indexMemUsage++; \
		}

	for( i=0; i < numfaces; i++ ) {
		int curInd = index[redir[mface[i].mat_nr+16383]];
		object->faceRemap[curInd] = i; 
		ADDLINK( mface[i].v1, curInd*3 );
		ADDLINK( mface[i].v2, curInd*3+1 );
		ADDLINK( mface[i].v3, curInd*3+2 );
		if( mface[i].v4 ) {
			object->faceRemap[curInd+1] = i;
			ADDLINK( mface[i].v3, curInd*3+3 );
			ADDLINK( mface[i].v4, curInd*3+4 );
			ADDLINK( mface[i].v1, curInd*3+5 );

			index[redir[mface[i].mat_nr+16383]]+=2;
		}
		else {
			index[redir[mface[i].mat_nr+16383]]++;
		}
	}

	for( i = 0; i < object->nindices; i++ ) {
		if( object->indices[i].element == -1 ) {
			object->indices[i].element = object->nelements + object->nlooseverts;
			object->nlooseverts++;
		}
	}
#undef ADDLINK

	MEM_freeN(index);
	return object;
}

void GPU_drawobject_free( DerivedMesh *dm )
{
	GPUDrawObject *object;

	DEBUG_VBO("GPU_drawobject_free\n");

	if( dm == 0 )
		return;
	object = dm->drawObject;
	if( object == 0 )
		return;

	MEM_freeN(object->materials);
	MEM_freeN(object->faceRemap);
	MEM_freeN(object->indices);
	MEM_freeN(object->indexMem);
	GPU_buffer_free( object->vertices, globalPool );
	GPU_buffer_free( object->normals, globalPool );
	GPU_buffer_free( object->uv, globalPool );
	GPU_buffer_free( object->colors, globalPool );
	GPU_buffer_free( object->edges, globalPool );
	GPU_buffer_free( object->uvedges, globalPool );

	MEM_freeN(object);
	dm->drawObject = 0;
}

/* Convenience struct for building the VBO. */
typedef struct {
	float co[3];
	short no[3];
} VertexBufferFormat;

typedef struct {
	/* opengl buffer handles */
	GLuint vert_buf, index_buf;
	GLenum index_type;

	/* mesh pointers in case buffer allocation fails */
	MFace *mface;
	MVert *mvert;
	int *face_indices;
	int totface;

	/* grid pointers */
	DMGridData **grids;
	int *grid_indices;
	int totgrid;
	int gridsize;

	unsigned int tot_tri, tot_quad;
} GPU_Buffers;

void GPU_update_mesh_buffers(void *buffers_v, MVert *mvert,
			int *vert_indices, int totvert)
{
	GPU_Buffers *buffers = buffers_v;
	VertexBufferFormat *vert_data;
	int i;

	if(buffers->vert_buf) {
		/* Build VBO */
		glBindBufferARB(GL_ARRAY_BUFFER_ARB, buffers->vert_buf);
		glBufferDataARB(GL_ARRAY_BUFFER_ARB,
				 sizeof(VertexBufferFormat) * totvert,
				 NULL, GL_STATIC_DRAW_ARB);
		vert_data = glMapBufferARB(GL_ARRAY_BUFFER_ARB, GL_WRITE_ONLY_ARB);

		if(vert_data) {
			for(i = 0; i < totvert; ++i) {
				MVert *v = mvert + vert_indices[i];
				VertexBufferFormat *out = vert_data + i;

				copy_v3_v3(out->co, v->co);
				memcpy(out->no, v->no, sizeof(short) * 3);
			}

			glUnmapBufferARB(GL_ARRAY_BUFFER_ARB);
		}
		else {
			glDeleteBuffersARB(1, &buffers->vert_buf);
			buffers->vert_buf = 0;
		}

		glBindBufferARB(GL_ARRAY_BUFFER_ARB, 0);
	}

	buffers->mvert = mvert;
}

void *GPU_build_mesh_buffers(GHash *map, MVert *mvert, MFace *mface,
			int *face_indices, int totface,
			int *vert_indices, int tot_uniq_verts,
			int totvert)
{
	GPU_Buffers *buffers;
	unsigned short *tri_data;
	int i, j, k, tottri;

	buffers = MEM_callocN(sizeof(GPU_Buffers), "GPU_Buffers");
	buffers->index_type = GL_UNSIGNED_SHORT;

	/* Count the number of triangles */
	for(i = 0, tottri = 0; i < totface; ++i)
		tottri += mface[face_indices[i]].v4 ? 2 : 1;
	
	if(GL_ARB_vertex_buffer_object && !(U.gameflags & USER_DISABLE_VBO))
		glGenBuffersARB(1, &buffers->index_buf);

	if(buffers->index_buf) {
		/* Generate index buffer object */
		glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, buffers->index_buf);
		glBufferDataARB(GL_ELEMENT_ARRAY_BUFFER_ARB,
				 sizeof(unsigned short) * tottri * 3, NULL, GL_STATIC_DRAW_ARB);

		/* Fill the triangle buffer */
		tri_data = glMapBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, GL_WRITE_ONLY_ARB);
		if(tri_data) {
			for(i = 0; i < totface; ++i) {
				MFace *f = mface + face_indices[i];
				int v[3] = {f->v1, f->v2, f->v3};

				for(j = 0; j < (f->v4 ? 2 : 1); ++j) {
					for(k = 0; k < 3; ++k) {
						void *value, *key = SET_INT_IN_POINTER(v[k]);
						int vbo_index;

						value = BLI_ghash_lookup(map, key);
						vbo_index = GET_INT_FROM_POINTER(value);

						if(vbo_index < 0) {
							vbo_index = -vbo_index +
								tot_uniq_verts - 1;
						}

						*tri_data = vbo_index;
						++tri_data;
					}
					v[0] = f->v4;
					v[1] = f->v1;
					v[2] = f->v3;
				}
			}
			glUnmapBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB);
		}
		else {
			glDeleteBuffersARB(1, &buffers->index_buf);
			buffers->index_buf = 0;
		}

		glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, 0);
	}

	if(buffers->index_buf)
		glGenBuffersARB(1, &buffers->vert_buf);
	GPU_update_mesh_buffers(buffers, mvert, vert_indices, totvert);

	buffers->tot_tri = tottri;

	buffers->mface = mface;
	buffers->face_indices = face_indices;
	buffers->totface = totface;

	return buffers;
}

void GPU_update_grid_buffers(void *buffers_v, DMGridData **grids,
	int *grid_indices, int totgrid, int gridsize, int smooth)
{
	GPU_Buffers *buffers = buffers_v;
	DMGridData *vert_data;
	int i, j, k, totvert;

	totvert= gridsize*gridsize*totgrid;

	/* Build VBO */
	if(buffers->vert_buf) {
		glBindBufferARB(GL_ARRAY_BUFFER_ARB, buffers->vert_buf);
		glBufferDataARB(GL_ARRAY_BUFFER_ARB,
				 sizeof(DMGridData) * totvert,
				 NULL, GL_STATIC_DRAW_ARB);
		vert_data = glMapBufferARB(GL_ARRAY_BUFFER_ARB, GL_WRITE_ONLY_ARB);
		if(vert_data) {
			for(i = 0; i < totgrid; ++i) {
				DMGridData *grid= grids[grid_indices[i]];
				memcpy(vert_data, grid, sizeof(DMGridData)*gridsize*gridsize);

				if(!smooth) {
					/* for flat shading, recalc normals and set the last vertex of
					   each quad in the index buffer to have the flat normal as
					   that is what opengl will use */
					for(j = 0; j < gridsize-1; ++j) {
						for(k = 0; k < gridsize-1; ++k) {
							normal_quad_v3(vert_data[(j+1)*gridsize + (k+1)].no,
								vert_data[(j+1)*gridsize + k].co,
								vert_data[(j+1)*gridsize + k+1].co,
								vert_data[j*gridsize + k+1].co,
								vert_data[j*gridsize + k].co);
						}
					}
				}

				vert_data += gridsize*gridsize;
			}
			glUnmapBufferARB(GL_ARRAY_BUFFER_ARB);
		}
		else {
			glDeleteBuffersARB(1, &buffers->vert_buf);
			buffers->vert_buf = 0;
		}
		glBindBufferARB(GL_ARRAY_BUFFER_ARB, 0);
	}

	buffers->grids = grids;
	buffers->grid_indices = grid_indices;
	buffers->totgrid = totgrid;
	buffers->gridsize = gridsize;

	//printf("node updated %p\n", buffers_v);
}

void *GPU_build_grid_buffers(DMGridData **grids,
	int *grid_indices, int totgrid, int gridsize)
{
	GPU_Buffers *buffers;
	int i, j, k, totquad, offset= 0;

	buffers = MEM_callocN(sizeof(GPU_Buffers), "GPU_Buffers");

	/* Count the number of quads */
	totquad= (gridsize-1)*(gridsize-1)*totgrid;

	/* Generate index buffer object */
	if(GL_ARB_vertex_buffer_object && !(U.gameflags & USER_DISABLE_VBO))
		glGenBuffersARB(1, &buffers->index_buf);

	if(buffers->index_buf) {
		glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, buffers->index_buf);

		if(totquad < USHRT_MAX) {
			unsigned short *quad_data;

			buffers->index_type = GL_UNSIGNED_SHORT;
			glBufferDataARB(GL_ELEMENT_ARRAY_BUFFER_ARB,
					 sizeof(unsigned short) * totquad * 4, NULL, GL_STATIC_DRAW_ARB);

			/* Fill the quad buffer */
			quad_data = glMapBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, GL_WRITE_ONLY_ARB);
			if(quad_data) {
				for(i = 0; i < totgrid; ++i) {
					for(j = 0; j < gridsize-1; ++j) {
						for(k = 0; k < gridsize-1; ++k) {
							*(quad_data++)= offset + j*gridsize + k+1;
							*(quad_data++)= offset + j*gridsize + k;
							*(quad_data++)= offset + (j+1)*gridsize + k;
							*(quad_data++)= offset + (j+1)*gridsize + k+1;
						}
					}

					offset += gridsize*gridsize;
				}
				glUnmapBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB);
			}
			else {
				glDeleteBuffersARB(1, &buffers->index_buf);
				buffers->index_buf = 0;
			}
		}
		else {
			unsigned int *quad_data;

			buffers->index_type = GL_UNSIGNED_INT;
			glBufferDataARB(GL_ELEMENT_ARRAY_BUFFER_ARB,
					 sizeof(unsigned int) * totquad * 4, NULL, GL_STATIC_DRAW_ARB);

			/* Fill the quad buffer */
			quad_data = glMapBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, GL_WRITE_ONLY_ARB);

			if(quad_data) {
				for(i = 0; i < totgrid; ++i) {
					for(j = 0; j < gridsize-1; ++j) {
						for(k = 0; k < gridsize-1; ++k) {
							*(quad_data++)= offset + j*gridsize + k+1;
							*(quad_data++)= offset + j*gridsize + k;
							*(quad_data++)= offset + (j+1)*gridsize + k;
							*(quad_data++)= offset + (j+1)*gridsize + k+1;
						}
					}

					offset += gridsize*gridsize;
				}
				glUnmapBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB);
			}
			else {
				glDeleteBuffersARB(1, &buffers->index_buf);
				buffers->index_buf = 0;
			}
		}

		glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, 0);
	}

	/* Build VBO */
	if(buffers->index_buf)
		glGenBuffersARB(1, &buffers->vert_buf);

	buffers->tot_quad = totquad;

	return buffers;
}

void GPU_draw_buffers(void *buffers_v)
{
	GPU_Buffers *buffers = buffers_v;

	if(buffers->vert_buf && buffers->index_buf) {
		glEnableClientState(GL_VERTEX_ARRAY);
		glEnableClientState(GL_NORMAL_ARRAY);

		glBindBufferARB(GL_ARRAY_BUFFER_ARB, buffers->vert_buf);
		glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, buffers->index_buf);

		if(buffers->tot_quad) {
			glVertexPointer(3, GL_FLOAT, sizeof(DMGridData), (void*)offsetof(DMGridData, co));
			glNormalPointer(GL_FLOAT, sizeof(DMGridData), (void*)offsetof(DMGridData, no));

			glDrawElements(GL_QUADS, buffers->tot_quad * 4, buffers->index_type, 0);
		}
		else {
			glVertexPointer(3, GL_FLOAT, sizeof(VertexBufferFormat), (void*)offsetof(VertexBufferFormat, co));
			glNormalPointer(GL_SHORT, sizeof(VertexBufferFormat), (void*)offsetof(VertexBufferFormat, no));

			glDrawElements(GL_TRIANGLES, buffers->tot_tri * 3, buffers->index_type, 0);
		}

		glBindBufferARB(GL_ARRAY_BUFFER_ARB, 0);
		glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, 0);

		glDisableClientState(GL_VERTEX_ARRAY);
		glDisableClientState(GL_NORMAL_ARRAY);
	}
	else if(buffers->totface) {
		/* fallback if we are out of memory */
		int i;

		for(i = 0; i < buffers->totface; ++i) {
			MFace *f = buffers->mface + buffers->face_indices[i];

			glBegin((f->v4)? GL_QUADS: GL_TRIANGLES);
			glNormal3sv(buffers->mvert[f->v1].no);
			glVertex3fv(buffers->mvert[f->v1].co);
			glNormal3sv(buffers->mvert[f->v2].no);
			glVertex3fv(buffers->mvert[f->v2].co);
			glNormal3sv(buffers->mvert[f->v3].no);
			glVertex3fv(buffers->mvert[f->v3].co);
			if(f->v4) {
				glNormal3sv(buffers->mvert[f->v4].no);
				glVertex3fv(buffers->mvert[f->v4].co);
			}
			glEnd();
		}
	}
	else if(buffers->totgrid) {
		int i, x, y, gridsize = buffers->gridsize;

		for(i = 0; i < buffers->totgrid; ++i) {
			DMGridData *grid = buffers->grids[buffers->grid_indices[i]];

			for(y = 0; y < gridsize-1; y++) {
				glBegin(GL_QUAD_STRIP);
				for(x = 0; x < gridsize; x++) {
					DMGridData *a = &grid[y*gridsize + x];
					DMGridData *b = &grid[(y+1)*gridsize + x];

					glNormal3fv(a->no);
					glVertex3fv(a->co);
					glNormal3fv(b->no);
					glVertex3fv(b->co);
				}
				glEnd();
			}
		}
	}
}

void GPU_free_buffers(void *buffers_v)
{
	if(buffers_v) {
		GPU_Buffers *buffers = buffers_v;
		
		if(buffers->vert_buf)
			glDeleteBuffersARB(1, &buffers->vert_buf);
		if(buffers->index_buf)
			glDeleteBuffersARB(1, &buffers->index_buf);

		MEM_freeN(buffers);
	}
}

GPUBuffer *GPU_buffer_setup( DerivedMesh *dm, GPUDrawObject *object, int size, GLenum target, void *user, void (*copy_f)(DerivedMesh *, float *, int *, int *, void *) )
{
	GPUBuffer *buffer;
	float *varray;
	int redir[32768];
	int *index;
	int i;
	int success;
	GLboolean uploaded;

	DEBUG_VBO("GPU_buffer_setup\n");

	if( globalPool == 0 )
		globalPool = GPU_buffer_pool_new();

	buffer = GPU_buffer_alloc(size,globalPool);
	if( buffer == 0 ) {
		dm->drawObject->legacy = 1;
	}
	if( dm->drawObject->legacy ) {
		return 0;
	}

	index = MEM_mallocN(sizeof(int)*object->nmaterials,"GPU_buffer_setup");
	for( i = 0; i < object->nmaterials; i++ ) {
		index[i] = object->materials[i].start*3;
		redir[object->materials[i].mat_nr+16383] = i;
	}

	if( useVBOs ) {
		success = 0;
		while( success == 0 ) {
			glBindBufferARB( target, buffer->id );
			glBufferDataARB( target, buffer->size, 0, GL_STATIC_DRAW_ARB );	/* discard previous data, avoid stalling gpu */
			varray = glMapBufferARB( target, GL_WRITE_ONLY_ARB );
			if( varray == 0 ) {
				DEBUG_VBO( "Failed to map buffer to client address space\n" ); 
				GPU_buffer_free( buffer, globalPool );
				GPU_buffer_pool_delete_last( globalPool );
				buffer= NULL;
				if( globalPool->size > 0 ) {
					GPU_buffer_pool_delete_last( globalPool );
					buffer = GPU_buffer_alloc( size, globalPool );
					if( buffer == 0 ) {
						dm->drawObject->legacy = 1;
						success = 1;
					}
				}
				else {
					dm->drawObject->legacy = 1;
					success = 1;
				}
			}
			else {
				success = 1;
			}
		}

		if( dm->drawObject->legacy == 0 ) {
			uploaded = GL_FALSE;
			while( !uploaded ) {
				(*copy_f)( dm, varray, index, redir, user );
				uploaded = glUnmapBufferARB( target );	/* returns false if data got corruped during transfer */
			}
		}
		glBindBufferARB(target, 0);
	}
	else {
		if( buffer->pointer != 0 ) {
			varray = buffer->pointer;
			(*copy_f)( dm, varray, index, redir, user );
		}
		else {
			dm->drawObject->legacy = 1;
		}
	}

	MEM_freeN(index);

	return buffer;
}

void GPU_buffer_copy_vertex( DerivedMesh *dm, float *varray, int *index, int *redir, void *user )
{
	int start;
	int i, j, numfaces;

	MVert *mvert;
	MFace *mface;

	DEBUG_VBO("GPU_buffer_copy_vertex\n");

	mvert = dm->getVertArray(dm);
	mface = dm->getFaceArray(dm);

	numfaces= dm->getNumFaces(dm);
	for( i=0; i < numfaces; i++ ) {
		start = index[redir[mface[i].mat_nr+16383]];
		if( mface[i].v4 )
			index[redir[mface[i].mat_nr+16383]] += 18;
		else
			index[redir[mface[i].mat_nr+16383]] += 9;

		/* v1 v2 v3 */
		VECCOPY(&varray[start],mvert[mface[i].v1].co);
		VECCOPY(&varray[start+3],mvert[mface[i].v2].co);
		VECCOPY(&varray[start+6],mvert[mface[i].v3].co);

		if( mface[i].v4 ) {
			/* v3 v4 v1 */
			VECCOPY(&varray[start+9],mvert[mface[i].v3].co);
			VECCOPY(&varray[start+12],mvert[mface[i].v4].co);
			VECCOPY(&varray[start+15],mvert[mface[i].v1].co);
		}
	}
	j = dm->drawObject->nelements*3;
	for( i = 0; i < dm->drawObject->nindices; i++ ) {
		if( dm->drawObject->indices[i].element >= dm->drawObject->nelements ) {
			VECCOPY(&varray[j],mvert[i].co);
			j+=3;
		}
	}
}

GPUBuffer *GPU_buffer_vertex( DerivedMesh *dm )
{
	DEBUG_VBO("GPU_buffer_vertex\n");

	return GPU_buffer_setup( dm, dm->drawObject, sizeof(float)*3*(dm->drawObject->nelements+dm->drawObject->nlooseverts), GL_ARRAY_BUFFER_ARB, 0, GPU_buffer_copy_vertex);
}

void GPU_buffer_copy_normal( DerivedMesh *dm, float *varray, int *index, int *redir, void *user )
{
	int i, numfaces;
	int start;
	float norm[3];

	float *nors= dm->getFaceDataArray(dm, CD_NORMAL);
	MVert *mvert = dm->getVertArray(dm);
	MFace *mface = dm->getFaceArray(dm);

	DEBUG_VBO("GPU_buffer_copy_normal\n");

	numfaces= dm->getNumFaces(dm);
	for( i=0; i < numfaces; i++ ) {
		start = index[redir[mface[i].mat_nr+16383]];
		if( mface[i].v4 )
			index[redir[mface[i].mat_nr+16383]] += 18;
		else
			index[redir[mface[i].mat_nr+16383]] += 9;

		/* v1 v2 v3 */
		if( mface[i].flag & ME_SMOOTH ) {
			VECCOPY(&varray[start],mvert[mface[i].v1].no);
			VECCOPY(&varray[start+3],mvert[mface[i].v2].no);
			VECCOPY(&varray[start+6],mvert[mface[i].v3].no);
		}
		else {
			if( nors ) {
				VECCOPY(&varray[start],&nors[i*3]);
				VECCOPY(&varray[start+3],&nors[i*3]);
				VECCOPY(&varray[start+6],&nors[i*3]);
			}
			if( mface[i].v4 )
				normal_quad_v3( norm,mvert[mface[i].v1].co, mvert[mface[i].v2].co, mvert[mface[i].v3].co, mvert[mface[i].v4].co);
			else
				normal_tri_v3( norm,mvert[mface[i].v1].co, mvert[mface[i].v2].co, mvert[mface[i].v3].co);
			VECCOPY(&varray[start],norm);
			VECCOPY(&varray[start+3],norm);
			VECCOPY(&varray[start+6],norm);
		}

		if( mface[i].v4 ) {
			/* v3 v4 v1 */
			if( mface[i].flag & ME_SMOOTH ) {
				VECCOPY(&varray[start+9],mvert[mface[i].v3].no);
				VECCOPY(&varray[start+12],mvert[mface[i].v4].no);
				VECCOPY(&varray[start+15],mvert[mface[i].v1].no);
			}
			else {
				VECCOPY(&varray[start+9],norm);
				VECCOPY(&varray[start+12],norm);
				VECCOPY(&varray[start+15],norm);
			}
		}
	}
}

GPUBuffer *GPU_buffer_normal( DerivedMesh *dm )
{
	DEBUG_VBO("GPU_buffer_normal\n");

	return GPU_buffer_setup( dm, dm->drawObject, sizeof(float)*3*dm->drawObject->nelements, GL_ARRAY_BUFFER_ARB, 0, GPU_buffer_copy_normal);
}

void GPU_buffer_copy_uv( DerivedMesh *dm, float *varray, int *index, int *redir, void *user )
{
	int start;
	int i, numfaces;

	MTFace *mtface;
	MFace *mface;

	DEBUG_VBO("GPU_buffer_copy_uv\n");

	mface = dm->getFaceArray(dm);
	mtface = DM_get_face_data_layer(dm, CD_MTFACE);

	if( mtface == 0 ) {
		DEBUG_VBO("Texture coordinates do not exist for this mesh");
		return;
	}
		
	numfaces= dm->getNumFaces(dm);
	for( i=0; i < numfaces; i++ ) {
		start = index[redir[mface[i].mat_nr+16383]];
		if( mface[i].v4 )
			index[redir[mface[i].mat_nr+16383]] += 12;
		else
			index[redir[mface[i].mat_nr+16383]] += 6;

		/* v1 v2 v3 */
		VECCOPY2D(&varray[start],mtface[i].uv[0]);
		VECCOPY2D(&varray[start+2],mtface[i].uv[1]);
		VECCOPY2D(&varray[start+4],mtface[i].uv[2]);

		if( mface[i].v4 ) {
			/* v3 v4 v1 */
			VECCOPY2D(&varray[start+6],mtface[i].uv[2]);
			VECCOPY2D(&varray[start+8],mtface[i].uv[3]);
			VECCOPY2D(&varray[start+10],mtface[i].uv[0]);
		}
	}
}

GPUBuffer *GPU_buffer_uv( DerivedMesh *dm )
{
	DEBUG_VBO("GPU_buffer_uv\n");
	if( DM_get_face_data_layer(dm, CD_MTFACE) != 0 ) /* was sizeof(float)*2 but caused buffer overrun  */
		return GPU_buffer_setup( dm, dm->drawObject, sizeof(float)*3*dm->drawObject->nelements, GL_ARRAY_BUFFER_ARB, 0, GPU_buffer_copy_uv);
	else
		return 0;
}

void GPU_buffer_copy_color3( DerivedMesh *dm, float *varray_, int *index, int *redir, void *user )
{
	int i, numfaces;
	unsigned char *varray = (unsigned char *)varray_;
	unsigned char *mcol = (unsigned char *)user;
	MFace *mface = dm->getFaceArray(dm);

	DEBUG_VBO("GPU_buffer_copy_color3\n");

	numfaces= dm->getNumFaces(dm);
	for( i=0; i < numfaces; i++ ) {
		int start = index[redir[mface[i].mat_nr+16383]];
		if( mface[i].v4 )
			index[redir[mface[i].mat_nr+16383]] += 18;
		else
			index[redir[mface[i].mat_nr+16383]] += 9;

		/* v1 v2 v3 */
		VECCOPY(&varray[start],&mcol[i*12]);
		VECCOPY(&varray[start+3],&mcol[i*12+3]);
		VECCOPY(&varray[start+6],&mcol[i*12+6]);
		if( mface[i].v4 ) {
			/* v3 v4 v1 */
			VECCOPY(&varray[start+9],&mcol[i*12+6]);
			VECCOPY(&varray[start+12],&mcol[i*12+9]);
			VECCOPY(&varray[start+15],&mcol[i*12]);
		}
	}
}

void GPU_buffer_copy_color4( DerivedMesh *dm, float *varray_, int *index, int *redir, void *user )
{
	int i, numfaces;
	unsigned char *varray = (unsigned char *)varray_;
	unsigned char *mcol = (unsigned char *)user;
	MFace *mface = dm->getFaceArray(dm);

	DEBUG_VBO("GPU_buffer_copy_color4\n");

	numfaces= dm->getNumFaces(dm);
	for( i=0; i < numfaces; i++ ) {
		int start = index[redir[mface[i].mat_nr+16383]];
		if( mface[i].v4 )
			index[redir[mface[i].mat_nr+16383]] += 18;
		else
			index[redir[mface[i].mat_nr+16383]] += 9;

		/* v1 v2 v3 */
		VECCOPY(&varray[start],&mcol[i*16]);
		VECCOPY(&varray[start+3],&mcol[i*16+4]);
		VECCOPY(&varray[start+6],&mcol[i*16+8]);
		if( mface[i].v4 ) {
			/* v3 v4 v1 */
			VECCOPY(&varray[start+9],&mcol[i*16+8]);
			VECCOPY(&varray[start+12],&mcol[i*16+12]);
			VECCOPY(&varray[start+15],&mcol[i*16]);
		}
	}
}

GPUBuffer *GPU_buffer_color( DerivedMesh *dm )
{
	unsigned char *colors;
	int i, numfaces;
	MCol *mcol;
	GPUBuffer *result;
	DEBUG_VBO("GPU_buffer_color\n");

	mcol = DM_get_face_data_layer(dm, CD_ID_MCOL);
	dm->drawObject->colType = CD_ID_MCOL;
	if(!mcol) {
		mcol = DM_get_face_data_layer(dm, CD_WEIGHT_MCOL);
		dm->drawObject->colType = CD_WEIGHT_MCOL;
	}
	if(!mcol) {
		mcol = DM_get_face_data_layer(dm, CD_MCOL);
		dm->drawObject->colType = CD_MCOL;
	}

	numfaces= dm->getNumFaces(dm);
	colors = MEM_mallocN(numfaces*12*sizeof(unsigned char), "GPU_buffer_color");
	for( i=0; i < numfaces*4; i++ ) {
		colors[i*3] = mcol[i].b;
		colors[i*3+1] = mcol[i].g;
		colors[i*3+2] = mcol[i].r;
	}

	result = GPU_buffer_setup( dm, dm->drawObject, sizeof(char)*3*dm->drawObject->nelements, GL_ARRAY_BUFFER_ARB, colors, GPU_buffer_copy_color3 );

	MEM_freeN(colors);
	return result;
}

void GPU_buffer_copy_edge( DerivedMesh *dm, float *varray, int *index, int *redir, void *user )
{
	int i;

	MVert *mvert;
	MEdge *medge;
	unsigned int *varray_ = (unsigned int *)varray;
	int numedges;
 
	DEBUG_VBO("GPU_buffer_copy_edge\n");

	mvert = dm->getVertArray(dm);
	medge = dm->getEdgeArray(dm);

	numedges= dm->getNumEdges(dm);
	for(i = 0; i < numedges; i++) {
		varray_[i*2] = (unsigned int)dm->drawObject->indices[medge[i].v1].element;
		varray_[i*2+1] = (unsigned int)dm->drawObject->indices[medge[i].v2].element;
	}
}

GPUBuffer *GPU_buffer_edge( DerivedMesh *dm )
{
	DEBUG_VBO("GPU_buffer_edge\n");

	return GPU_buffer_setup( dm, dm->drawObject, sizeof(int)*2*dm->drawObject->nedges, GL_ELEMENT_ARRAY_BUFFER_ARB, 0, GPU_buffer_copy_edge);
}

void GPU_buffer_copy_uvedge( DerivedMesh *dm, float *varray, int *index, int *redir, void *user )
{
	MTFace *tf = DM_get_face_data_layer(dm, CD_MTFACE);
	int i, j=0;

	DEBUG_VBO("GPU_buffer_copy_uvedge\n");

	if(tf) {
		for(i = 0; i < dm->numFaceData; i++, tf++) {
			MFace mf;
			dm->getFace(dm,i,&mf);

			VECCOPY2D(&varray[j],tf->uv[0]);
			VECCOPY2D(&varray[j+2],tf->uv[1]);

			VECCOPY2D(&varray[j+4],tf->uv[1]);
			VECCOPY2D(&varray[j+6],tf->uv[2]);

			if(!mf.v4) {
				VECCOPY2D(&varray[j+8],tf->uv[2]);
				VECCOPY2D(&varray[j+10],tf->uv[0]);
				j+=12;
			} else {
				VECCOPY2D(&varray[j+8],tf->uv[2]);
				VECCOPY2D(&varray[j+10],tf->uv[3]);

				VECCOPY2D(&varray[j+12],tf->uv[3]);
				VECCOPY2D(&varray[j+14],tf->uv[0]);
				j+=16;
			}
		}
	}
	else {
		DEBUG_VBO("Could not get MTFACE data layer");
	}
}

GPUBuffer *GPU_buffer_uvedge( DerivedMesh *dm )
{
	DEBUG_VBO("GPU_buffer_uvedge\n");

	return GPU_buffer_setup( dm, dm->drawObject, sizeof(float)*2*(dm->drawObject->nelements/3)*2, GL_ARRAY_BUFFER_ARB, 0, GPU_buffer_copy_uvedge);
}


void GPU_vertex_setup( DerivedMesh *dm )
{
	DEBUG_VBO("GPU_vertex_setup\n");
	if( dm->drawObject == 0 )
		dm->drawObject = GPU_drawobject_new( dm );
	if( dm->drawObject->vertices == 0 )
		dm->drawObject->vertices = GPU_buffer_vertex( dm );
	if( dm->drawObject->vertices == 0 ) {
		DEBUG_VBO( "Failed to setup vertices\n" );
		return;
	}

	glEnableClientState( GL_VERTEX_ARRAY );
	if( useVBOs ) {
		glBindBufferARB( GL_ARRAY_BUFFER_ARB, dm->drawObject->vertices->id );
		glVertexPointer( 3, GL_FLOAT, 0, 0 );
	}
	else {
		glVertexPointer( 3, GL_FLOAT, 0, dm->drawObject->vertices->pointer );
	}
	
	GLStates |= GPU_BUFFER_VERTEX_STATE;
}

void GPU_normal_setup( DerivedMesh *dm )
{
	DEBUG_VBO("GPU_normal_setup\n");
	if( dm->drawObject == 0 )
		dm->drawObject = GPU_drawobject_new( dm );
	if( dm->drawObject->normals == 0 )
		dm->drawObject->normals = GPU_buffer_normal( dm );
	if( dm->drawObject->normals == 0 ) {
		DEBUG_VBO( "Failed to setup normals\n" );
		return;
	}
	glEnableClientState( GL_NORMAL_ARRAY );
	if( useVBOs ) {
		glBindBufferARB( GL_ARRAY_BUFFER_ARB, dm->drawObject->normals->id );
		glNormalPointer( GL_FLOAT, 0, 0 );
	}
	else {
		glNormalPointer( GL_FLOAT, 0, dm->drawObject->normals->pointer );
	}

	GLStates |= GPU_BUFFER_NORMAL_STATE;
}

void GPU_uv_setup( DerivedMesh *dm )
{
	DEBUG_VBO("GPU_uv_setup\n");
	if( dm->drawObject == 0 )
		dm->drawObject = GPU_drawobject_new( dm );
	if( dm->drawObject->uv == 0 )
		dm->drawObject->uv = GPU_buffer_uv( dm );
	
	if( dm->drawObject->uv != 0 ) {
		glEnableClientState( GL_TEXTURE_COORD_ARRAY );
		if( useVBOs ) {
			glBindBufferARB( GL_ARRAY_BUFFER_ARB, dm->drawObject->uv->id );
			glTexCoordPointer( 2, GL_FLOAT, 0, 0 );
		}
		else {
			glTexCoordPointer( 2, GL_FLOAT, 0, dm->drawObject->uv->pointer );
		}

		GLStates |= GPU_BUFFER_TEXCOORD_STATE;
	}
}

void GPU_color_setup( DerivedMesh *dm )
{
	DEBUG_VBO("GPU_color_setup\n");
	if( dm->drawObject == 0 )
		dm->drawObject = GPU_drawobject_new( dm );
	if( dm->drawObject->colors == 0 )
		dm->drawObject->colors = GPU_buffer_color( dm );
	if( dm->drawObject->colors == 0 ) {
		DEBUG_VBO( "Failed to setup colors\n" );
		return;
	}
	glEnableClientState( GL_COLOR_ARRAY );
	if( useVBOs ) {
		glBindBufferARB( GL_ARRAY_BUFFER_ARB, dm->drawObject->colors->id );
		glColorPointer( 3, GL_UNSIGNED_BYTE, 0, 0 );
	}
	else {
		glColorPointer( 3, GL_UNSIGNED_BYTE, 0, dm->drawObject->colors->pointer );
	}

	GLStates |= GPU_BUFFER_COLOR_STATE;
}

void GPU_edge_setup( DerivedMesh *dm )
{
	DEBUG_VBO("GPU_edge_setup\n");
	if( dm->drawObject == 0 )
		dm->drawObject = GPU_drawobject_new( dm );
	if( dm->drawObject->edges == 0 )
		dm->drawObject->edges = GPU_buffer_edge( dm );
	if( dm->drawObject->edges == 0 ) {
		DEBUG_VBO( "Failed to setup edges\n" );
		return;
	}
	if( dm->drawObject->vertices == 0 )
		dm->drawObject->vertices = GPU_buffer_vertex( dm );
	if( dm->drawObject->vertices == 0 ) {
		DEBUG_VBO( "Failed to setup vertices\n" );
		return;
	}

	glEnableClientState( GL_VERTEX_ARRAY );
	if( useVBOs ) {
		glBindBufferARB( GL_ARRAY_BUFFER_ARB, dm->drawObject->vertices->id );
		glVertexPointer( 3, GL_FLOAT, 0, 0 );
	}
	else {
		glVertexPointer( 3, GL_FLOAT, 0, dm->drawObject->vertices->pointer );
	}
	
	GLStates |= GPU_BUFFER_VERTEX_STATE;

	if( useVBOs ) {
		glBindBufferARB( GL_ELEMENT_ARRAY_BUFFER_ARB, dm->drawObject->edges->id );
	}

	GLStates |= GPU_BUFFER_ELEMENT_STATE;
}

void GPU_uvedge_setup( DerivedMesh *dm )
{
	DEBUG_VBO("GPU_uvedge_setup\n");
	if( dm->drawObject == 0 )
		dm->drawObject = GPU_drawobject_new( dm );
	if( dm->drawObject->uvedges == 0 )
		dm->drawObject->uvedges = GPU_buffer_uvedge( dm );
	if( dm->drawObject->uvedges == 0 ) {
		DEBUG_VBO( "Failed to setup UV edges\n" );
		return;
	}

	glEnableClientState( GL_VERTEX_ARRAY );
	if( useVBOs ) {
		glBindBufferARB( GL_ARRAY_BUFFER_ARB, dm->drawObject->uvedges->id );
		glVertexPointer( 2, GL_FLOAT, 0, 0 );
	}
	else {
		glVertexPointer( 2, GL_FLOAT, 0, dm->drawObject->uvedges->pointer );
	}
	
	GLStates |= GPU_BUFFER_VERTEX_STATE;
}

void GPU_interleaved_setup( GPUBuffer *buffer, int data[] ) {
	int i;
	int elementsize = 0;
	intptr_t offset = 0;

	DEBUG_VBO("GPU_interleaved_setup\n");

	for( i = 0; data[i] != GPU_BUFFER_INTER_END; i++ ) {
		switch( data[i] ) {
			case GPU_BUFFER_INTER_V3F:
				elementsize += 3*sizeof(float);
				break;
			case GPU_BUFFER_INTER_N3F:
				elementsize += 3*sizeof(float);
				break;
			case GPU_BUFFER_INTER_T2F:
				elementsize += 2*sizeof(float);
				break;
			case GPU_BUFFER_INTER_C3UB:
				elementsize += 3*sizeof(unsigned char);
				break;
			case GPU_BUFFER_INTER_C4UB:
				elementsize += 4*sizeof(unsigned char);
				break;
			default:
				DEBUG_VBO( "Unknown element in data type array in GPU_interleaved_setup\n" );
		}
	}

	if( useVBOs ) {
		glBindBufferARB( GL_ARRAY_BUFFER_ARB, buffer->id );
		for( i = 0; data[i] != GPU_BUFFER_INTER_END; i++ ) {
			switch( data[i] ) {
				case GPU_BUFFER_INTER_V3F:
					glEnableClientState( GL_VERTEX_ARRAY );
					glVertexPointer( 3, GL_FLOAT, elementsize, (void *)offset );
					GLStates |= GPU_BUFFER_VERTEX_STATE;
					offset += 3*sizeof(float);
					break;
				case GPU_BUFFER_INTER_N3F:
					glEnableClientState( GL_NORMAL_ARRAY );
					glNormalPointer( GL_FLOAT, elementsize, (void *)offset );
					GLStates |= GPU_BUFFER_NORMAL_STATE;
					offset += 3*sizeof(float);
					break;
				case GPU_BUFFER_INTER_T2F:
					glEnableClientState( GL_TEXTURE_COORD_ARRAY );
					glTexCoordPointer( 2, GL_FLOAT, elementsize, (void *)offset );
					GLStates |= GPU_BUFFER_TEXCOORD_STATE;
					offset += 2*sizeof(float);
					break;
				case GPU_BUFFER_INTER_C3UB:
					glEnableClientState( GL_COLOR_ARRAY );
					glColorPointer( 3, GL_UNSIGNED_BYTE, elementsize, (void *)offset );
					GLStates |= GPU_BUFFER_COLOR_STATE;
					offset += 3*sizeof(unsigned char);
					break;
				case GPU_BUFFER_INTER_C4UB:
					glEnableClientState( GL_COLOR_ARRAY );
					glColorPointer( 4, GL_UNSIGNED_BYTE, elementsize, (void *)offset );
					GLStates |= GPU_BUFFER_COLOR_STATE;
					offset += 4*sizeof(unsigned char);
					break;
			}
		}
	}
	else {
		for( i = 0; data[i] != GPU_BUFFER_INTER_END; i++ ) {
			switch( data[i] ) {
				case GPU_BUFFER_INTER_V3F:
					glEnableClientState( GL_VERTEX_ARRAY );
					glVertexPointer( 3, GL_FLOAT, elementsize, offset+(char *)buffer->pointer );
					GLStates |= GPU_BUFFER_VERTEX_STATE;
					offset += 3*sizeof(float);
					break;
				case GPU_BUFFER_INTER_N3F:
					glEnableClientState( GL_NORMAL_ARRAY );
					glNormalPointer( GL_FLOAT, elementsize, offset+(char *)buffer->pointer );
					GLStates |= GPU_BUFFER_NORMAL_STATE;
					offset += 3*sizeof(float);
					break;
				case GPU_BUFFER_INTER_T2F:
					glEnableClientState( GL_TEXTURE_COORD_ARRAY );
					glTexCoordPointer( 2, GL_FLOAT, elementsize, offset+(char *)buffer->pointer );
					GLStates |= GPU_BUFFER_TEXCOORD_STATE;
					offset += 2*sizeof(float);
					break;
				case GPU_BUFFER_INTER_C3UB:
					glEnableClientState( GL_COLOR_ARRAY );
					glColorPointer( 3, GL_UNSIGNED_BYTE, elementsize, offset+(char *)buffer->pointer );
					GLStates |= GPU_BUFFER_COLOR_STATE;
					offset += 3*sizeof(unsigned char);
					break;
				case GPU_BUFFER_INTER_C4UB:
					glEnableClientState( GL_COLOR_ARRAY );
					glColorPointer( 4, GL_UNSIGNED_BYTE, elementsize, offset+(char *)buffer->pointer );
					GLStates |= GPU_BUFFER_COLOR_STATE;
					offset += 4*sizeof(unsigned char);
					break;
			}
		}
	}
}

static int GPU_typesize( int type ) {
	switch( type ) {
		case GL_FLOAT:
			return sizeof(float);
		case GL_INT:
			return sizeof(int);
		case GL_UNSIGNED_INT:
			return sizeof(unsigned int);
		case GL_BYTE:
			return sizeof(char);
		case GL_UNSIGNED_BYTE:
			return sizeof(unsigned char);
		default:
			return 0;
	}
}

int GPU_attrib_element_size( GPUAttrib data[], int numdata ) {
	int i, elementsize = 0;

	for( i = 0; i < numdata; i++ ) {
		int typesize = GPU_typesize(data[i].type);
		if( typesize == 0 )
			DEBUG_VBO( "Unknown element in data type array in GPU_attrib_element_size\n" );
		else {
			elementsize += typesize*data[i].size;
		}
	}
	return elementsize;
}

void GPU_interleaved_attrib_setup( GPUBuffer *buffer, GPUAttrib data[], int numdata ) {
	int i;
	int elementsize;
	intptr_t offset = 0;

	DEBUG_VBO("GPU_interleaved_attrib_setup\n");

	for( i = 0; i < MAX_GPU_ATTRIB_DATA; i++ ) {
		if( attribData[i].index != -1 ) {
			glDisableVertexAttribArrayARB( attribData[i].index );
		}
		else
			break;
	}
	elementsize = GPU_attrib_element_size( data, numdata );

	if( useVBOs ) {
		glBindBufferARB( GL_ARRAY_BUFFER_ARB, buffer->id );
		for( i = 0; i < numdata; i++ ) {
			glEnableVertexAttribArrayARB( data[i].index );
			glVertexAttribPointerARB( data[i].index, data[i].size, data[i].type, GL_TRUE, elementsize, (void *)offset );
			offset += data[i].size*GPU_typesize(data[i].type);

			attribData[i].index = data[i].index;
			attribData[i].size = data[i].size;
			attribData[i].type = data[i].type;
		}
		attribData[numdata].index = -1;
	}
	else {
		for( i = 0; i < numdata; i++ ) {
			glEnableVertexAttribArrayARB( data[i].index );
			glVertexAttribPointerARB( data[i].index, data[i].size, data[i].type, GL_TRUE, elementsize, (char *)buffer->pointer + offset );
			offset += data[i].size*GPU_typesize(data[i].type);
		}
	}
}


void GPU_buffer_unbind()
{
	int i;
	DEBUG_VBO("GPU_buffer_unbind\n");

	if( GLStates & GPU_BUFFER_VERTEX_STATE )
		glDisableClientState( GL_VERTEX_ARRAY );
	if( GLStates & GPU_BUFFER_NORMAL_STATE )
		glDisableClientState( GL_NORMAL_ARRAY );
	if( GLStates & GPU_BUFFER_TEXCOORD_STATE )
		glDisableClientState( GL_TEXTURE_COORD_ARRAY );
	if( GLStates & GPU_BUFFER_COLOR_STATE )
		glDisableClientState( GL_COLOR_ARRAY );
	if( GLStates & GPU_BUFFER_ELEMENT_STATE ) {
		if( useVBOs ) {
			glBindBufferARB( GL_ELEMENT_ARRAY_BUFFER_ARB, 0 );
		}
	}
	GLStates &= !(GPU_BUFFER_VERTEX_STATE | GPU_BUFFER_NORMAL_STATE | GPU_BUFFER_TEXCOORD_STATE | GPU_BUFFER_COLOR_STATE | GPU_BUFFER_ELEMENT_STATE);

	for( i = 0; i < MAX_GPU_ATTRIB_DATA; i++ ) {
		if( attribData[i].index != -1 ) {
			glDisableVertexAttribArrayARB( attribData[i].index );
		}
		else
			break;
	}
	if( GLStates != 0 ) {
		DEBUG_VBO( "Some weird OpenGL state is still set. Why?" );
	}
	if( useVBOs )
		glBindBufferARB( GL_ARRAY_BUFFER_ARB, 0 );
}

void GPU_color3_upload( DerivedMesh *dm, unsigned char *data )
{
	if( dm->drawObject == 0 )
		dm->drawObject = GPU_drawobject_new(dm);
	GPU_buffer_free(dm->drawObject->colors,globalPool);
	dm->drawObject->colors = GPU_buffer_setup( dm, dm->drawObject, sizeof(char)*3*dm->drawObject->nelements, GL_ARRAY_BUFFER_ARB, data, GPU_buffer_copy_color3 );
}
void GPU_color4_upload( DerivedMesh *dm, unsigned char *data )
{
	if( dm->drawObject == 0 )
		dm->drawObject = GPU_drawobject_new(dm);
	GPU_buffer_free(dm->drawObject->colors,globalPool);
	dm->drawObject->colors = GPU_buffer_setup( dm, dm->drawObject, sizeof(char)*3*dm->drawObject->nelements, GL_ARRAY_BUFFER_ARB, data, GPU_buffer_copy_color4 );
}

void GPU_color_switch( int mode )
{
	if( mode ) {
		if( !(GLStates & GPU_BUFFER_COLOR_STATE) )
			glEnableClientState( GL_COLOR_ARRAY );
		GLStates |= GPU_BUFFER_COLOR_STATE;
	}
	else {
		if( GLStates & GPU_BUFFER_COLOR_STATE )
			glDisableClientState( GL_COLOR_ARRAY );
		GLStates &= (!GPU_BUFFER_COLOR_STATE);
	}
}

int GPU_buffer_legacy( DerivedMesh *dm )
{
	int test= (U.gameflags & USER_DISABLE_VBO);
	if( test )
		return 1;

	if( dm->drawObject == 0 )
		dm->drawObject = GPU_drawobject_new(dm);
	return dm->drawObject->legacy;
}

void *GPU_buffer_lock( GPUBuffer *buffer )
{
	float *varray;

	DEBUG_VBO("GPU_buffer_lock\n");
	if( buffer == 0 ) {
		DEBUG_VBO( "Failed to lock NULL buffer\n" );
		return 0;
	}

	if( useVBOs ) {
		glBindBufferARB( GL_ARRAY_BUFFER_ARB, buffer->id );
		varray = glMapBufferARB( GL_ARRAY_BUFFER_ARB, GL_WRITE_ONLY_ARB );
		if( varray == 0 ) {
			DEBUG_VBO( "Failed to map buffer to client address space\n" ); 
		}
		return varray;
	}
	else {
		return buffer->pointer;
	}
}

void *GPU_buffer_lock_stream( GPUBuffer *buffer )
{
	float *varray;

	DEBUG_VBO("GPU_buffer_lock_stream\n");
	if( buffer == 0 ) {
		DEBUG_VBO( "Failed to lock NULL buffer\n" );
		return 0;
	}

	if( useVBOs ) {
		glBindBufferARB( GL_ARRAY_BUFFER_ARB, buffer->id );
		glBufferDataARB( GL_ARRAY_BUFFER_ARB, buffer->size, 0, GL_STREAM_DRAW_ARB );	/* discard previous data, avoid stalling gpu */
		varray = glMapBufferARB( GL_ARRAY_BUFFER_ARB, GL_WRITE_ONLY_ARB );
		if( varray == 0 ) {
			DEBUG_VBO( "Failed to map buffer to client address space\n" ); 
		}
		return varray;
	}
	else {
		return buffer->pointer;
	}
}

void GPU_buffer_unlock( GPUBuffer *buffer )
{
	DEBUG_VBO( "GPU_buffer_unlock\n" ); 
	if( useVBOs ) {
		if( buffer != 0 ) {
			if( glUnmapBufferARB( GL_ARRAY_BUFFER_ARB ) == 0 ) {
				DEBUG_VBO( "Failed to copy new data\n" ); 
			}
		}
		glBindBufferARB(GL_ARRAY_BUFFER_ARB, 0);
	}
}

void GPU_buffer_draw_elements( GPUBuffer *elements, unsigned int mode, int start, int count )
{
	if( useVBOs ) {
		glDrawElements( mode, count, GL_UNSIGNED_INT, (void *)(start*sizeof(unsigned int)) );
	}
	else {
		glDrawElements( mode, count, GL_UNSIGNED_INT, ((int *)elements->pointer)+start );
	}
}