/*
* Mesa 3-D graphics library
* Version: 6.5
*
* 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
* BRIAN PAUL 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 <keith@tungstengraphics.com>
*/
/* Deal with hardware and/or swtnl maximums:
* - maximum number of vertices in buffer
* - maximum number of elements (maybe zero)
*
* The maximums may vary with opengl state (eg if a larger hardware
* vertex is required in this state, the maximum number of vertices
* may be smaller than in another state).
*
* We want buffer splitting to be a convenience function for the code
* actually drawing the primitives rather than a system-wide maximum,
* otherwise it is hard to avoid pessimism.
*
* For instance, if a driver has no hardware limits on vertex buffer
* dimensions, it would not ordinarily want to split vbos. But if
* there is an unexpected fallback, eg memory manager fails to upload
* textures, it will want to pass the drawing commands onto swtnl,
* which does have limitations. A convenience function allows swtnl
* to split the drawing and vbos internally without imposing its
* limitations on drivers which want to use it as a fallback path.
*/
#include "main/glheader.h"
#include "main/imports.h"
#include "main/mtypes.h"
#include "main/macros.h"
#include "vbo_split.h"
#include "vbo.h"
/* True if a primitive can be split without copying of vertices, false
* otherwise.
*/
GLboolean split_prim_inplace(GLenum mode, GLuint *first, GLuint *incr)
{
switch (mode) {
case GL_POINTS:
*first = 1;
*incr = 1;
return GL_TRUE;
case GL_LINES:
*first = 2;
*incr = 2;
return GL_TRUE;
case GL_LINE_STRIP:
*first = 2;
*incr = 1;
return GL_TRUE;
case GL_TRIANGLES:
*first = 3;
*incr = 3;
return GL_TRUE;
case GL_TRIANGLE_STRIP:
*first = 3;
*incr = 1;
return GL_TRUE;
case GL_QUADS:
*first = 4;
*incr = 4;
return GL_TRUE;
case GL_QUAD_STRIP:
*first = 4;
*incr = 2;
return GL_TRUE;
default:
*first = 0;
*incr = 1; /* so that count % incr works */
return GL_FALSE;
}
}
void vbo_split_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,
const struct split_limits *limits )
{
GLint max_basevertex = prim->basevertex;
GLuint i;
for (i = 1; i < nr_prims; i++)
max_basevertex = MAX2(max_basevertex, prim[i].basevertex);
/* XXX max_basevertex is computed but not used, why? */
if (ib) {
if (limits->max_indices == 0) {
/* Could traverse the indices, re-emitting vertices in turn.
* But it's hard to see why this case would be needed - for
* software tnl, it is better to convert to non-indexed
* rendering after transformation is complete, as is done in
* the t_dd_rendertmp.h templates. Are there any devices
* with hardware tnl that cannot do indexed rendering?
*
* For now, this path is disabled.
*/
}
else if (max_index - min_index >= limits->max_verts) {
/* The vertex buffers are too large for hardware (or the
* swtnl module). Traverse the indices, re-emitting vertices
* in turn. Use a vertex cache to preserve some of the
* sharing from the original index list.
*/
vbo_split_copy(ctx, arrays, prim, nr_prims, ib,
draw, limits );
}
else if (ib->count > limits->max_indices) {
/* The index buffer is too large for hardware. Try to split
* on whole-primitive boundaries, otherwise try to split the
* individual primitives.
*/
vbo_split_inplace(ctx, arrays, prim, nr_prims, ib,
min_index, max_index, draw, limits );
}
else {
/* Why were we called? */
}
}
else {
if (max_index - min_index >= limits->max_verts) {
/* The vertex buffer is too large for hardware (or the swtnl
* module). Try to split on whole-primitive boundaries,
* otherwise try to split the individual primitives.
*/
vbo_split_inplace(ctx, arrays, prim, nr_prims, ib,
min_index, max_index, draw, limits );
}
else {
/* Why were we called? */
}
}
}