src/mesa/vbo/vbo_rebase.c

   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@vmware.com>
  27  */
  28
  29 /* Helper for drivers which find themselves rendering a range of
  30  * indices starting somewhere above zero.  Typically the application
  31  * is issuing multiple DrawArrays() or DrawElements() to draw
  32  * successive primitives layed out linearly in the vertex arrays.
  33  * Unless the vertex arrays are all in a VBO, the OpenGL semantics
  34  * imply that we need to re-upload the vertex data on each draw call.
  35  * In that case, we want to avoid starting the upload at zero, as it
  36  * will mean every draw call uploads an increasing amount of not-used
  37  * vertex data.  Worse - in the software tnl module, all those
  38  * vertices will be transformed and lit.
  39  *
  40  * If we just upload the new data, however, the indices will be
  41  * incorrect as we tend to upload each set of vertex data to a new
  42  * region.
  43  *
  44  * This file provides a helper to adjust the arrays, primitives and
  45  * indices of a draw call so that it can be re-issued with a min_index
  46  * of zero.
  47  */
  48
  49 #include <stdio.h>
  50 #include "main/glheader.h"
  51 #include "main/imports.h"
  52 #include "main/mtypes.h"
  53
  54 #include "vbo.h"
  55
  56
  57 #define REBASE(TYPE)                                            \
  58 static void *rebase_##TYPE( const void *ptr,                    \
  59                           GLuint count,                         \
  60                           TYPE min_index )                      \
  61 {                                                               \
  62    GLuint i;                                                    \
  63    const TYPE *in = (TYPE *)ptr;                                \
  64    TYPE *tmp_indices = malloc(count * sizeof(TYPE));            \
  65                                                                 \
  66    if (tmp_indices == NULL) {                                   \
  67       _mesa_error_no_memory(__func__);                          \
  68       return NULL;                                              \
  69    }                                                            \
  70                                                                 \
  71    for (i = 0; i < count; i++)                                  \
  72       tmp_indices[i] = in[i] - min_index;                       \
  73                                                                 \
  74    return (void *)tmp_indices;                                  \
  75 }
  76
  77
  78 REBASE(GLuint)
  79 REBASE(GLushort)
  80 REBASE(GLubyte)
  81
  82 GLboolean vbo_all_varyings_in_vbos( const struct gl_vertex_array *arrays[] )
  83 {
  84    GLuint i;
  85
  86    for (i = 0; i < VERT_ATTRIB_MAX; i++)
  87       if (arrays[i]->StrideB &&
  88           arrays[i]->BufferObj->Name == 0)
  89          return GL_FALSE;
  90
  91    return GL_TRUE;
  92 }
  93
  94
  95 /* Adjust primitives, indices and vertex definitions so that min_index
  96  * becomes zero. There are lots of reasons for wanting to do this, eg:
  97  *
  98  * Software tnl:
  99  *    - any time min_index != 0, otherwise unused vertices lower than
 100  *      min_index will be transformed.
 101  *
 102  * Hardware tnl:
 103  *    - if ib != NULL and min_index != 0, otherwise vertices lower than
 104  *      min_index will be uploaded.  Requires adjusting index values.
 105  *
 106  *    - if ib == NULL and min_index != 0, just for convenience so this doesn't
 107  *      have to be handled within the driver.
 108  *
 109  * Hardware tnl with VBO support:
 110  *    - as above, but only when vertices are not (all?) in VBO's.
 111  *    - can't save time by trying to upload half a vbo - typically it is
 112  *      all or nothing.
 113  */
 114 void vbo_rebase_prims( struct gl_context *ctx,
 115                        const struct gl_vertex_array *arrays[],
 116                        const struct _mesa_prim *prim,
 117                        GLuint nr_prims,
 118                        const struct _mesa_index_buffer *ib,
 119                        GLuint min_index,
 120                        GLuint max_index,
 121                        vbo_draw_func draw )
 122 {
 123    struct gl_vertex_array tmp_arrays[VERT_ATTRIB_MAX];
 124    const struct gl_vertex_array *tmp_array_pointers[VERT_ATTRIB_MAX];
 125
 126    struct _mesa_index_buffer tmp_ib;
 127    struct _mesa_prim *tmp_prims = NULL;
 128    const struct gl_vertex_array **saved_arrays = ctx->Array._DrawArrays;
 129    void *tmp_indices = NULL;
 130    GLuint i;
 131
 132    assert(min_index != 0);
 133
 134    if (0)
 135       printf("%s %d..%d\n", __func__, min_index, max_index);
 136
 137
 138    /* XXX this path is disabled for now.
 139     * There's rendering corruption in some apps when it's enabled.
 140     */
 141    if (0 && ib && ctx->Extensions.ARB_draw_elements_base_vertex) {
 142       /* If we can just tell the hardware or the TNL to interpret our
 143        * indices with a different base, do so.
 144        */
 145       tmp_prims = malloc(sizeof(*prim) * nr_prims);
 146
 147       if (tmp_prims == NULL) {
 148          _mesa_error_no_memory(__func__);
 149          return;
 150       }
 151
 152       for (i = 0; i < nr_prims; i++) {
 153          tmp_prims[i] = prim[i];
 154          tmp_prims[i].basevertex -= min_index;
 155       }
 156
 157       prim = tmp_prims;
 158    } else if (ib) {
 159       /* Unfortunately need to adjust each index individually.
 160        */
 161       GLboolean map_ib = ib->obj->Name &&
 162                          !ib->obj->Mappings[MAP_INTERNAL].Pointer;
 163       void *ptr;
 164
 165       if (map_ib)
 166          ctx->Driver.MapBufferRange(ctx, 0, ib->obj->Size, GL_MAP_READ_BIT,
 167                                     ib->obj, MAP_INTERNAL);
 168
 169
 170       ptr = ADD_POINTERS(ib->obj->Mappings[MAP_INTERNAL].Pointer, ib->ptr);
 171
 172       /* Some users might prefer it if we translated elements to
 173        * GLuints here.  Others wouldn't...
 174        */
 175       switch (ib->index_size) {
 176       case 4:
 177          tmp_indices = rebase_GLuint( ptr, ib->count, min_index );
 178          break;
 179       case 2:
 180          tmp_indices = rebase_GLushort( ptr, ib->count, min_index );
 181          break;
 182       case 1:
 183          tmp_indices = rebase_GLubyte( ptr, ib->count, min_index );
 184          break;
 185       }
 186
 187       if (map_ib)
 188          ctx->Driver.UnmapBuffer(ctx, ib->obj, MAP_INTERNAL);
 189
 190       if (tmp_indices == NULL) {
 191          return;
 192       }
 193
 194       tmp_ib.obj = ctx->Shared->NullBufferObj;
 195       tmp_ib.ptr = tmp_indices;
 196       tmp_ib.count = ib->count;
 197       tmp_ib.index_size = ib->index_size;
 198
 199       ib = &tmp_ib;
 200    }
 201    else {
 202       /* Otherwise the primitives need adjustment.
 203        */
 204       tmp_prims = malloc(sizeof(*prim) * nr_prims);
 205
 206       if (tmp_prims == NULL) {
 207          _mesa_error_no_memory(__func__);
 208          return;
 209       }
 210
 211       for (i = 0; i < nr_prims; i++) {
 212          /* If this fails, it could indicate an application error:
 213           */
 214          assert(prim[i].start >= min_index);
 215
 216          tmp_prims[i] = prim[i];
 217          tmp_prims[i].start -= min_index;
 218       }
 219
 220       prim = tmp_prims;
 221    }
 222
 223    /* Just need to adjust the pointer values on each incoming array.
 224     * This works for VBO and non-vbo rendering and shouldn't pesimize
 225     * VBO-based upload schemes.  However this may still not be a fast
 226     * path for hardware tnl for VBO based rendering as most machines
 227     * will be happier if you just specify a starting vertex value in
 228     * each primitive.
 229     *
 230     * For drivers with hardware tnl, you only want to do this if you
 231     * are forced to, eg non-VBO indexed rendering with start != 0.
 232     */
 233    for (i = 0; i < VERT_ATTRIB_MAX; i++) {
 234       tmp_arrays[i] = *arrays[i];
 235       tmp_arrays[i].Ptr += min_index * tmp_arrays[i].StrideB;
 236       tmp_array_pointers[i] = &tmp_arrays[i];
 237    }
 238
 239    /* Re-issue the draw call.
 240     */
 241    ctx->Array._DrawArrays = tmp_array_pointers;
 242    ctx->NewDriverState |= ctx->DriverFlags.NewArray;
 243
 244    draw( ctx,
 245          prim,
 246          nr_prims,
 247          ib,
 248          GL_TRUE,
 249          0,
 250          max_index - min_index,
 251          NULL, 0, NULL );
 252
 253    ctx->Array._DrawArrays = saved_arrays;
 254    ctx->NewDriverState |= ctx->DriverFlags.NewArray;
 255
 256    free(tmp_indices);
 257
 258    free(tmp_prims);
 259 }
 260
 261
 262