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