1 2 /* 3 * Mesa 3-D graphics library 4 * 5 * Copyright (C) 1999-2006 Brian Paul All Rights Reserved. 6 * 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: 13 * 14 * The above copyright notice and this permission notice shall be included 15 * in all copies or substantial portions of the Software. 16 * 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. 24 * 25 * Authors: 26 * Keith Whitwell <keithw (at) vmware.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 */ 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 99 100 101 void vbo_split_prims( struct gl_context *ctx, 102 const struct gl_vertex_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 if (ib) { 112 if (limits->max_indices == 0) { 113 /* Could traverse the indices, re-emitting vertices in turn. 114 * But it's hard to see why this case would be needed - for 115 * software tnl, it is better to convert to non-indexed 116 * rendering after transformation is complete. Are there any devices 117 * with hardware tnl that cannot do indexed rendering? 118 * 119 * For now, this path is disabled. 120 */ 121 assert(0); 122 } 123 else if (max_index - min_index >= limits->max_verts) { 124 /* The vertex buffers are too large for hardware (or the 125 * swtnl module). Traverse the indices, re-emitting vertices 126 * in turn. Use a vertex cache to preserve some of the 127 * sharing from the original index list. 128 */ 129 vbo_split_copy(ctx, arrays, prim, nr_prims, ib, 130 draw, limits ); 131 } 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. 136 */ 137 vbo_split_inplace(ctx, arrays, prim, nr_prims, ib, 138 min_index, max_index, draw, limits ); 139 } 140 else { 141 /* Why were we called? */ 142 assert(0); 143 } 144 } 145 else { 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. 150 */ 151 vbo_split_inplace(ctx, arrays, prim, nr_prims, ib, 152 min_index, max_index, draw, limits ); 153 } 154 else { 155 /* Why were we called? */ 156 assert(0); 157 } 158 } 159 } 160 161
