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 * Mesa 3-D graphics library

 *

 * Copyright (C) 1999-2006  Brian Paul   All Rights Reserved.

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and associated documentation files (the "Software"),

 * to deal in the Software without restriction, including without limitation

 * the rights to use, copy, modify, merge, publish, distribute, sublicense,

 * and/or sell copies of the Software, and to permit persons to whom the

 * Software is furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included

 * in all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS

 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR

 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,

 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR

 * OTHER DEALINGS IN THE SOFTWARE.

 *

 * Authors:

 *    Keith Whitwell 

 */

 * indices starting somewhere above zero.  Typically the application

 * is issuing multiple DrawArrays() or DrawElements() to draw

 * successive primitives layed out linearly in the vertex arrays.

 * Unless the vertex arrays are all in a VBO, the OpenGL semantics

 * imply that we need to re-upload the vertex data on each draw call.

 * In that case, we want to avoid starting the upload at zero, as it

 * will mean every draw call uploads an increasing amount of not-used

 * vertex data.  Worse - in the software tnl module, all those

 * vertices will be transformed and lit.

 *

 * If we just upload the new data, however, the indices will be

 * incorrect as we tend to upload each set of vertex data to a new

 * region.

 *

 * This file provides a helper to adjust the arrays, primitives and

 * indices of a draw call so that it can be re-issued with a min_index

 * of zero.

 */

#include "main/imports.h"

#include "main/mtypes.h"

static void *rebase_##TYPE( const void *ptr,			\

			  GLuint count, 			\

			  TYPE min_index )			\

{								\

   const TYPE *in = (TYPE *)ptr;				\

   TYPE *tmp_indices = malloc(count * sizeof(TYPE));	\

   GLuint i;							\

								\

   for (i = 0; i < count; i++)  				\

      tmp_indices[i] = in[i] - min_index;			\

								\

   return (void *)tmp_indices;					\

}

REBASE(GLushort)

REBASE(GLubyte)

{

   GLuint i;

      if (arrays[i]->StrideB &&

	  arrays[i]->BufferObj->Name == 0)

	 return GL_FALSE;

}

{

   GLuint i;

      if (arrays[i]->BufferObj->Name != 0)

	 return GL_TRUE;

}

 * becomes zero. There are lots of reasons for wanting to do this, eg:

 *

 * Software tnl:

 *    - any time min_index != 0, otherwise unused vertices lower than

 *      min_index will be transformed.

 *

 * Hardware tnl:

 *    - if ib != NULL and min_index != 0, otherwise vertices lower than

 *      min_index will be uploaded.  Requires adjusting index values.

 *

 *    - if ib == NULL and min_index != 0, just for convenience so this doesn't

 *      have to be handled within the driver.

 *

 * Hardware tnl with VBO support:

 *    - as above, but only when vertices are not (all?) in VBO's.

 *    - can't save time by trying to upload half a vbo - typically it is

 *      all or nothing.

 */

void vbo_rebase_prims( struct gl_context *ctx,

		       const struct gl_client_array *arrays[],

		       const struct _mesa_prim *prim,

		       GLuint nr_prims,

		       const struct _mesa_index_buffer *ib,

		       GLuint min_index,

		       GLuint max_index,

		       vbo_draw_func draw )

{

   struct gl_client_array tmp_arrays[VERT_ATTRIB_MAX];

   const struct gl_client_array *tmp_array_pointers[VERT_ATTRIB_MAX];

   struct _mesa_prim *tmp_prims = NULL;

   const struct gl_client_array **saved_arrays = ctx->Array._DrawArrays;

   void *tmp_indices = NULL;

   GLuint i;

      printf("%s %d..%d\n", __FUNCTION__, min_index, max_index);

    * There's rendering corruption in some apps when it's enabled.

    */

   if (0 && ib && ctx->Extensions.ARB_draw_elements_base_vertex) {

      /* If we can just tell the hardware or the TNL to interpret our

       * indices with a different base, do so.

       */

      tmp_prims = malloc(sizeof(*prim) * nr_prims);

	 tmp_prims[i] = prim[i];

	 tmp_prims[i].basevertex -= min_index;

      }

   } else if (ib) {

      /* Unfortunately need to adjust each index individually.

       */

      GLboolean map_ib = ib->obj->Name && !ib->obj->Pointer;

      void *ptr;

	 ctx->Driver.MapBufferRange(ctx, 0, ib->obj->Size, GL_MAP_READ_BIT,

				    ib->obj);

       * GLuints here.  Others wouldn't...

       */

      switch (ib->type) {

      case GL_UNSIGNED_INT:

	 tmp_indices = rebase_GLuint( ptr, ib->count, min_index );

	 break;

      case GL_UNSIGNED_SHORT:

	 tmp_indices = rebase_GLushort( ptr, ib->count, min_index );

	 break;

      case GL_UNSIGNED_BYTE:

	 tmp_indices = rebase_GLubyte( ptr, ib->count, min_index );

	 break;

      }

	 ctx->Driver.UnmapBuffer(ctx, ib->obj);

      tmp_ib.ptr = tmp_indices;

      tmp_ib.count = ib->count;

      tmp_ib.type = ib->type;

   }

   else {

      /* Otherwise the primitives need adjustment.

       */

      tmp_prims = malloc(sizeof(*prim) * nr_prims);

	 /* If this fails, it could indicate an application error:

	  */

	 assert(prim[i].start >= min_index);

	 tmp_prims[i].start -= min_index;

      }

   }

    * This works for VBO and non-vbo rendering and shouldn't pesimize

    * VBO-based upload schemes.  However this may still not be a fast

    * path for hardware tnl for VBO based rendering as most machines

    * will be happier if you just specify a starting vertex value in

    * each primitive.

    *

    * For drivers with hardware tnl, you only want to do this if you

    * are forced to, eg non-VBO indexed rendering with start != 0.

    */

   for (i = 0; i < VERT_ATTRIB_MAX; i++) {

      tmp_arrays[i] = *arrays[i];

      tmp_arrays[i].Ptr += min_index * tmp_arrays[i].StrideB;

      tmp_array_pointers[i] = &tmp_arrays[i];

   }

    */

   ctx->Array._DrawArrays = tmp_array_pointers;

   ctx->NewDriverState |= ctx->DriverFlags.NewArray;

	 prim,

	 nr_prims,

	 ib,

	 GL_TRUE,

	 0,

	 max_index - min_index,

	 NULL );

   ctx->NewDriverState |= ctx->DriverFlags.NewArray;

}