src/mesa/vbo/vbo_rebase.c

   1
   2 /*
   3  * Mesa 3-D graphics library
   4  * Version:  6.5
   5  *
   6  * Copyright (C) 1999-2006  Brian Paul   All Rights Reserved.
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a
   9  * copy of this software and associated documentation files (the "Software"),
  10  * to deal in the Software without restriction, including without limitation
  11  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  12  * and/or sell copies of the Software, and to permit persons to whom the
  13  * Software is furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included
  16  * in all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  21  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  22  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  23  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  24  *
  25  * Authors:
  26  *    Keith Whitwell <keith@tungstengraphics.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 "main/glheader.h"
  50 #include "main/imports.h"
  51 #include "main/mtypes.h"
  52
  53 #include "vbo.h"
  54
  55
  56 #define REBASE(TYPE)                                            \
  57 static void *rebase_##TYPE( const void *ptr,                    \
  58                           GLuint count,                         \
  59                           TYPE min_index )                      \
  60 {                                                               \
  61    const TYPE *in = (TYPE *)ptr;                                \
  62    TYPE *tmp_indices = malloc(count * sizeof(TYPE));    \
  63    GLuint i;                                                    \
  64                                                                 \
  65    for (i = 0; i < count; i++)                                  \
  66       tmp_indices[i] = in[i] - min_index;                       \
  67                                                                 \
  68    return (void *)tmp_indices;                                  \
  69 }
  70
  71
  72 REBASE(GLuint)
  73 REBASE(GLushort)
  74 REBASE(GLubyte)
  75
  76 GLboolean vbo_all_varyings_in_vbos( const struct gl_client_array *arrays[] )
  77 {
  78    GLuint i;
  79
  80    for (i = 0; i < VERT_ATTRIB_MAX; i++)
  81       if (arrays[i]->BufferObj->Name == 0)
  82          return GL_FALSE;
  83
  84    return GL_TRUE;
  85 }
  86
  87 GLboolean vbo_any_varyings_in_vbos( const struct gl_client_array *arrays[] )
  88 {
  89    GLuint i;
  90
  91    for (i = 0; i < VERT_ATTRIB_MAX; i++)
  92       if (arrays[i]->BufferObj->Name != 0)
  93          return GL_TRUE;
  94
  95    return GL_FALSE;
  96 }
  97
  98 /* Adjust primitives, indices and vertex definitions so that min_index
  99  * becomes zero. There are lots of reasons for wanting to do this, eg:
 100  *
 101  * Software tnl:
 102  *    - any time min_index != 0, otherwise unused vertices lower than
 103  *      min_index will be transformed.
 104  *
 105  * Hardware tnl:
 106  *    - if ib != NULL and min_index != 0, otherwise vertices lower than
 107  *      min_index will be uploaded.  Requires adjusting index values.
 108  *
 109  *    - if ib == NULL and min_index != 0, just for convenience so this doesn't
 110  *      have to be handled within the driver.
 111  *
 112  * Hardware tnl with VBO support:
 113  *    - as above, but only when vertices are not (all?) in VBO's.
 114  *    - can't save time by trying to upload half a vbo - typically it is
 115  *      all or nothing.
 116  */
 117 void vbo_rebase_prims( struct gl_context *ctx,
 118                        const struct gl_client_array *arrays[],
 119                        const struct _mesa_prim *prim,
 120                        GLuint nr_prims,
 121                        const struct _mesa_index_buffer *ib,
 122                        GLuint min_index,
 123                        GLuint max_index,
 124                        vbo_draw_func draw )
 125 {
 126    struct gl_client_array tmp_arrays[VERT_ATTRIB_MAX];
 127    const struct gl_client_array *tmp_array_pointers[VERT_ATTRIB_MAX];
 128
 129    struct _mesa_index_buffer tmp_ib;
 130    struct _mesa_prim *tmp_prims = NULL;
 131    void *tmp_indices = NULL;
 132    GLuint i;
 133
 134    assert(min_index != 0);
 135
 136    if (0)
 137       printf("%s %d..%d\n", __FUNCTION__, min_index, max_index);
 138
 139
 140    /* XXX this path is disabled for now.
 141     * There's rendering corruption in some apps when it's enabled.
 142     */
 143    if (0 && ib && ctx->Extensions.ARB_draw_elements_base_vertex) {
 144       /* If we can just tell the hardware or the TNL to interpret our
 145        * indices with a different base, do so.
 146        */
 147       tmp_prims = (struct _mesa_prim *)malloc(sizeof(*prim) * nr_prims);
 148
 149       for (i = 0; i < nr_prims; i++) {
 150          tmp_prims[i] = prim[i];
 151          tmp_prims[i].basevertex -= min_index;
 152       }
 153
 154       prim = tmp_prims;
 155    } else if (ib) {
 156       /* Unfortunately need to adjust each index individually.
 157        */
 158       GLboolean map_ib = ib->obj->Name && !ib->obj->Pointer;
 159       void *ptr;
 160
 161       if (map_ib)
 162          ctx->Driver.MapBuffer(ctx,
 163                                GL_ELEMENT_ARRAY_BUFFER,
 164                                GL_READ_ONLY_ARB,
 165                                ib->obj);
 166
 167
 168       ptr = ADD_POINTERS(ib->obj->Pointer, ib->ptr);
 169
 170       /* Some users might prefer it if we translated elements to
 171        * GLuints here.  Others wouldn't...
 172        */
 173       switch (ib->type) {
 174       case GL_UNSIGNED_INT:
 175          tmp_indices = rebase_GLuint( ptr, ib->count, min_index );
 176          break;
 177       case GL_UNSIGNED_SHORT:
 178          tmp_indices = rebase_GLushort( ptr, ib->count, min_index );
 179          break;
 180       case GL_UNSIGNED_BYTE:
 181          tmp_indices = rebase_GLubyte( ptr, ib->count, min_index );
 182          break;
 183       }
 184
 185       if (map_ib)
 186          ctx->Driver.UnmapBuffer(ctx,
 187                                  GL_ELEMENT_ARRAY_BUFFER,
 188                                  ib->obj);
 189
 190       tmp_ib.obj = ctx->Shared->NullBufferObj;
 191       tmp_ib.ptr = tmp_indices;
 192       tmp_ib.count = ib->count;
 193       tmp_ib.type = ib->type;
 194
 195       ib = &tmp_ib;
 196    }
 197    else {
 198       /* Otherwise the primitives need adjustment.
 199        */
 200       tmp_prims = (struct _mesa_prim *)malloc(sizeof(*prim) * nr_prims);
 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_arrays[i] = *arrays[i];
 226       tmp_arrays[i].Ptr += min_index * tmp_arrays[i].StrideB;
 227       tmp_array_pointers[i] = &tmp_arrays[i];
 228    }
 229
 230    /* Re-issue the draw call.
 231     */
 232    draw( ctx,
 233          tmp_array_pointers,
 234          prim,
 235          nr_prims,
 236          ib,
 237          GL_TRUE,
 238          0,
 239          max_index - min_index );
 240
 241    if (tmp_indices)
 242       free(tmp_indices);
 243
 244    if (tmp_prims)
 245       free(tmp_prims);
 246 }
 247
 248
 249