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