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 tnl_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                      GLuint num_instances,
 114                      GLuint base_instance,
 115                      tnl_draw_func draw )
 116 {
 117    struct gl_array_attributes tmp_attribs[VERT_ATTRIB_MAX];
 118    struct tnl_vertex_array tmp_arrays[VERT_ATTRIB_MAX];
 119
 120    struct _mesa_index_buffer tmp_ib;
 121    struct _mesa_prim *tmp_prims = NULL;
 122    void *tmp_indices = NULL;
 123    GLuint i;
 124
 125    assert(min_index != 0);
 126
 127    if (0)
 128       printf("%s %d..%d\n", __func__, min_index, max_index);
 129
 130
 131    /* XXX this path is disabled for now.
 132     * There's rendering corruption in some apps when it's enabled.
 133     */
 134    if (0 && ib && ctx->Extensions.ARB_draw_elements_base_vertex) {
 135       /* If we can just tell the hardware or the TNL to interpret our
 136        * indices with a different base, do so.
 137        */
 138       tmp_prims = malloc(sizeof(*prim) * nr_prims);
 139
 140       if (tmp_prims == NULL) {
 141          _mesa_error_no_memory(__func__);
 142          return;
 143       }
 144
 145       for (i = 0; i < nr_prims; i++) {
 146          tmp_prims[i] = prim[i];
 147          tmp_prims[i].basevertex -= min_index;
 148       }
 149
 150       prim = tmp_prims;
 151    } else if (ib) {
 152       /* Unfortunately need to adjust each index individually.
 153        */
 154       GLboolean map_ib = ib->obj->Name &&
 155                          !ib->obj->Mappings[MAP_INTERNAL].Pointer;
 156       void *ptr;
 157
 158       if (map_ib)
 159          ctx->Driver.MapBufferRange(ctx, 0, ib->obj->Size, GL_MAP_READ_BIT,
 160                                     ib->obj, MAP_INTERNAL);
 161
 162
 163       ptr = ADD_POINTERS(ib->obj->Mappings[MAP_INTERNAL].Pointer, ib->ptr);
 164
 165       /* Some users might prefer it if we translated elements to
 166        * GLuints here.  Others wouldn't...
 167        */
 168       switch (ib->index_size_shift) {
 169       case 2:
 170          tmp_indices = rebase_GLuint( ptr, ib->count, min_index );
 171          break;
 172       case 1:
 173          tmp_indices = rebase_GLushort( ptr, ib->count, min_index );
 174          break;
 175       case 0:
 176          tmp_indices = rebase_GLubyte( ptr, ib->count, min_index );
 177          break;
 178       }
 179
 180       if (map_ib)
 181          ctx->Driver.UnmapBuffer(ctx, ib->obj, MAP_INTERNAL);
 182
 183       if (tmp_indices == NULL) {
 184          return;
 185       }
 186
 187       tmp_ib.obj = ctx->Shared->NullBufferObj;
 188       tmp_ib.ptr = tmp_indices;
 189       tmp_ib.count = ib->count;
 190       tmp_ib.index_size_shift = ib->index_size_shift;
 191
 192       ib = &tmp_ib;
 193    }
 194    else {
 195       /* Otherwise the primitives need adjustment.
 196        */
 197       tmp_prims = malloc(sizeof(*prim) * nr_prims);
 198
 199       if (tmp_prims == NULL) {
 200          _mesa_error_no_memory(__func__);
 201          return;
 202       }
 203
 204       for (i = 0; i < nr_prims; i++) {
 205          /* If this fails, it could indicate an application error:
 206           */
 207          assert(prim[i].start >= min_index);
 208
 209          tmp_prims[i] = prim[i];
 210          tmp_prims[i].start -= min_index;
 211       }
 212
 213       prim = tmp_prims;
 214    }
 215
 216    /* Just need to adjust the pointer values on each incoming array.
 217     * This works for VBO and non-vbo rendering and shouldn't pesimize
 218     * VBO-based upload schemes.  However this may still not be a fast
 219     * path for hardware tnl for VBO based rendering as most machines
 220     * will be happier if you just specify a starting vertex value in
 221     * each primitive.
 222     *
 223     * For drivers with hardware tnl, you only want to do this if you
 224     * are forced to, eg non-VBO indexed rendering with start != 0.
 225     */
 226    for (i = 0; i < VERT_ATTRIB_MAX; i++) {
 227       tmp_attribs[i] = *(arrays[i].VertexAttrib);
 228       tmp_arrays[i].BufferBinding = arrays[i].BufferBinding;
 229       tmp_arrays[i].VertexAttrib = &tmp_attribs[i];
 230       if (_mesa_is_bufferobj(arrays[i].BufferBinding->BufferObj))
 231          tmp_attribs[i].RelativeOffset +=
 232             min_index * arrays[i].BufferBinding->Stride;
 233       else
 234          tmp_attribs[i].Ptr += min_index * arrays[i].BufferBinding->Stride;
 235    }
 236
 237    /* Re-issue the draw call.
 238     */
 239    draw( ctx,
 240          tmp_arrays,
 241          prim,
 242          nr_prims,
 243          ib,
 244          GL_TRUE,
 245          0,
 246          max_index - min_index,
 247          num_instances, base_instance,
 248          NULL, 0);
 249
 250    free(tmp_indices);
 251
 252    free(tmp_prims);
 253 }
 254
 255
 256