3 * Mesa 3-D graphics library
5 * Copyright (C) 1999-2006 Brian Paul All Rights Reserved.
7 * Permission is hereby granted, free of charge, to any person obtaining a
8 * copy of this software and associated documentation files (the "Software"),
9 * to deal in the Software without restriction, including without limitation
10 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
11 * and/or sell copies of the Software, and to permit persons to whom the
12 * Software is furnished to do so, subject to the following conditions:
14 * The above copyright notice and this permission notice shall be included
15 * in all copies or substantial portions of the Software.
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
18 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
21 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
22 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
23 * OTHER DEALINGS IN THE SOFTWARE.
26 * Keith Whitwell <keithw@vmware.com>
29 /* Deal with hardware and/or swtnl maximums:
30 * - maximum number of vertices in buffer
31 * - maximum number of elements (maybe zero)
33 * The maximums may vary with opengl state (eg if a larger hardware
34 * vertex is required in this state, the maximum number of vertices
35 * may be smaller than in another state).
37 * We want buffer splitting to be a convenience function for the code
38 * actually drawing the primitives rather than a system-wide maximum,
39 * otherwise it is hard to avoid pessimism.
41 * For instance, if a driver has no hardware limits on vertex buffer
42 * dimensions, it would not ordinarily want to split vbos. But if
43 * there is an unexpected fallback, eg memory manager fails to upload
44 * textures, it will want to pass the drawing commands onto swtnl,
45 * which does have limitations. A convenience function allows swtnl
46 * to split the drawing and vbos internally without imposing its
47 * limitations on drivers which want to use it as a fallback path.
50 #include "main/glheader.h"
51 #include "main/mtypes.h"
53 #include "vbo_split.h"
57 /* True if a primitive can be split without copying of vertices, false
61 split_prim_inplace(GLenum mode
, GLuint
*first
, GLuint
*incr
)
80 case GL_TRIANGLE_STRIP
:
94 *incr
= 1; /* so that count % incr works */
102 vbo_split_prims(struct gl_context
*ctx
,
103 const struct gl_vertex_array arrays
[],
104 const struct _mesa_prim
*prim
,
106 const struct _mesa_index_buffer
*ib
,
110 const struct split_limits
*limits
)
113 if (limits
->max_indices
== 0) {
114 /* Could traverse the indices, re-emitting vertices in turn.
115 * But it's hard to see why this case would be needed - for
116 * software tnl, it is better to convert to non-indexed
117 * rendering after transformation is complete. Are there any devices
118 * with hardware tnl that cannot do indexed rendering?
120 * For now, this path is disabled.
124 else if (max_index
- min_index
>= limits
->max_verts
) {
125 /* The vertex buffers are too large for hardware (or the
126 * swtnl module). Traverse the indices, re-emitting vertices
127 * in turn. Use a vertex cache to preserve some of the
128 * sharing from the original index list.
130 vbo_split_copy(ctx
, arrays
, prim
, nr_prims
, ib
, draw
, limits
);
132 else if (ib
->count
> limits
->max_indices
) {
133 /* The index buffer is too large for hardware. Try to split
134 * on whole-primitive boundaries, otherwise try to split the
135 * individual primitives.
137 vbo_split_inplace(ctx
, arrays
, prim
, nr_prims
, ib
,
138 min_index
, max_index
, draw
, limits
);
141 /* Why were we called? */
146 if (max_index
- min_index
>= limits
->max_verts
) {
147 /* The vertex buffer is too large for hardware (or the swtnl
148 * module). Try to split on whole-primitive boundaries,
149 * otherwise try to split the individual primitives.
151 vbo_split_inplace(ctx
, arrays
, prim
, nr_prims
, ib
,
152 min_index
, max_index
, draw
, limits
);
155 /* Why were we called? */