1
2 /*
3 * Mesa 3-D graphics library
4 * Version: 6.5
5 *
6 * Copyright (C) 1999-2006 Brian Paul All Rights Reserved.
7 *
8 * Permission is hereby granted, free of charge, to any person obtaining a
9 * copy of this software and associated documentation files (the "Software"),
10 * to deal in the Software without restriction, including without limitation
11 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
12 * and/or sell copies of the Software, and to permit persons to whom the
13 * Software is furnished to do so, subject to the following conditions:
14 *
15 * The above copyright notice and this permission notice shall be included
16 * in all copies or substantial portions of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
21 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
22 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
23 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
24 *
25 * Authors:
26 * Keith Whitwell <keith@tungstengraphics.com>
27 */
28
29 /* Deal with hardware and/or swtnl maximums:
30 * - maximum number of vertices in buffer
31 * - maximum number of elements (maybe zero)
32 *
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).
36 *
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.
40 *
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.
48 */
49
50 #include "main/glheader.h"
51 #include "main/imports.h"
52 #include "main/mtypes.h"
53 #include "main/macros.h"
54
55 #include "vbo_split.h"
56 #include "vbo.h"
57
58 /* True if a primitive can be split without copying of vertices, false
59 * otherwise.
60 */
split_prim_inplace(GLenum mode,GLuint * first,GLuint * incr)61 GLboolean split_prim_inplace(GLenum mode, GLuint *first, GLuint *incr)
62 {
63 switch (mode) {
64 case GL_POINTS:
65 *first = 1;
66 *incr = 1;
67 return GL_TRUE;
68 case GL_LINES:
69 *first = 2;
70 *incr = 2;
71 return GL_TRUE;
72 case GL_LINE_STRIP:
73 *first = 2;
74 *incr = 1;
75 return GL_TRUE;
76 case GL_TRIANGLES:
77 *first = 3;
78 *incr = 3;
79 return GL_TRUE;
80 case GL_TRIANGLE_STRIP:
81 *first = 3;
82 *incr = 1;
83 return GL_TRUE;
84 case GL_QUADS:
85 *first = 4;
86 *incr = 4;
87 return GL_TRUE;
88 case GL_QUAD_STRIP:
89 *first = 4;
90 *incr = 2;
91 return GL_TRUE;
92 default:
93 *first = 0;
94 *incr = 1; /* so that count % incr works */
95 return GL_FALSE;
96 }
97 }
98
99
100
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)101 void vbo_split_prims( struct gl_context *ctx,
102 const struct gl_client_array *arrays[],
103 const struct _mesa_prim *prim,
104 GLuint nr_prims,
105 const struct _mesa_index_buffer *ib,
106 GLuint min_index,
107 GLuint max_index,
108 vbo_draw_func draw,
109 const struct split_limits *limits )
110 {
111 GLint max_basevertex = prim->basevertex;
112 GLuint i;
113
114 for (i = 1; i < nr_prims; i++)
115 max_basevertex = MAX2(max_basevertex, prim[i].basevertex);
116
117 /* XXX max_basevertex is computed but not used, why? */
118
119 if (ib) {
120 if (limits->max_indices == 0) {
121 /* Could traverse the indices, re-emitting vertices in turn.
122 * But it's hard to see why this case would be needed - for
123 * software tnl, it is better to convert to non-indexed
124 * rendering after transformation is complete. Are there any devices
125 * with hardware tnl that cannot do indexed rendering?
126 *
127 * For now, this path is disabled.
128 */
129 assert(0);
130 }
131 else if (max_index - min_index >= limits->max_verts) {
132 /* The vertex buffers are too large for hardware (or the
133 * swtnl module). Traverse the indices, re-emitting vertices
134 * in turn. Use a vertex cache to preserve some of the
135 * sharing from the original index list.
136 */
137 vbo_split_copy(ctx, arrays, prim, nr_prims, ib,
138 draw, limits );
139 }
140 else if (ib->count > limits->max_indices) {
141 /* The index buffer is too large for hardware. Try to split
142 * on whole-primitive boundaries, otherwise try to split the
143 * individual primitives.
144 */
145 vbo_split_inplace(ctx, arrays, prim, nr_prims, ib,
146 min_index, max_index, draw, limits );
147 }
148 else {
149 /* Why were we called? */
150 assert(0);
151 }
152 }
153 else {
154 if (max_index - min_index >= limits->max_verts) {
155 /* The vertex buffer is too large for hardware (or the swtnl
156 * module). Try to split on whole-primitive boundaries,
157 * otherwise try to split the individual primitives.
158 */
159 vbo_split_inplace(ctx, arrays, prim, nr_prims, ib,
160 min_index, max_index, draw, limits );
161 }
162 else {
163 /* Why were we called? */
164 assert(0);
165 }
166 }
167 }
168
169