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 "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    GLuint i;                                                    \
  62    const TYPE *in = (TYPE *)ptr;                                \
  63    TYPE *tmp_indices = malloc(count * sizeof(TYPE));            \
  64                                                                 \
  65    if (tmp_indices == NULL) {                                   \
  66       _mesa_error_no_memory(__func__);                          \
  67       return NULL;                                              \
  68    }                                                            \
  69                                                                 \
  70    for (i = 0; i < count; i++)                                  \
  71       tmp_indices[i] = in[i] - min_index;                       \
  72                                                                 \
  73    return (void *)tmp_indices;                                  \
  74 }
  75
  76
  77 REBASE(GLuint)
  78 REBASE(GLushort)
  79 REBASE(GLubyte)
  80
  81 GLboolean vbo_all_varyings_in_vbos( const struct gl_client_array *arrays[] )
  82 {
  83    GLuint i;
  84
  85    for (i = 0; i < VERT_ATTRIB_MAX; i++)
  86       if (arrays[i]->StrideB &&
  87           arrays[i]->BufferObj->Name == 0)
  88          return GL_FALSE;
  89
  90    return GL_TRUE;
  91 }
  92
  93 GLboolean vbo_any_varyings_in_vbos( const struct gl_client_array *arrays[] )
  94 {
  95    GLuint i;
  96
  97    for (i = 0; i < VERT_ATTRIB_MAX; i++)
  98       if (arrays[i]->BufferObj->Name != 0)
  99          return GL_TRUE;
 100
 101    return GL_FALSE;
 102 }
 103
 104 /* Adjust primitives, indices and vertex definitions so that min_index
 105  * becomes zero. There are lots of reasons for wanting to do this, eg:
 106  *
 107  * Software tnl:
 108  *    - any time min_index != 0, otherwise unused vertices lower than
 109  *      min_index will be transformed.
 110  *
 111  * Hardware tnl:
 112  *    - if ib != NULL and min_index != 0, otherwise vertices lower than
 113  *      min_index will be uploaded.  Requires adjusting index values.
 114  *
 115  *    - if ib == NULL and min_index != 0, just for convenience so this doesn't
 116  *      have to be handled within the driver.
 117  *
 118  * Hardware tnl with VBO support:
 119  *    - as above, but only when vertices are not (all?) in VBO's.
 120  *    - can't save time by trying to upload half a vbo - typically it is
 121  *      all or nothing.
 122  */
 123 void vbo_rebase_prims( struct gl_context *ctx,
 124                        const struct gl_client_array *arrays[],
 125                        const struct _mesa_prim *prim,
 126                        GLuint nr_prims,
 127                        const struct _mesa_index_buffer *ib,
 128                        GLuint min_index,
 129                        GLuint max_index,
 130                        vbo_draw_func draw )
 131 {
 132    struct gl_client_array tmp_arrays[VERT_ATTRIB_MAX];
 133    const struct gl_client_array *tmp_array_pointers[VERT_ATTRIB_MAX];
 134
 135    struct _mesa_index_buffer tmp_ib;
 136    struct _mesa_prim *tmp_prims = NULL;
 137    const struct gl_client_array **saved_arrays = ctx->Array._DrawArrays;
 138    void *tmp_indices = NULL;
 139    GLuint i;
 140
 141    assert(min_index != 0);
 142
 143    if (0)
 144       printf("%s %d..%d\n", __FUNCTION__, min_index, max_index);
 145
 146
 147    /* XXX this path is disabled for now.
 148     * There's rendering corruption in some apps when it's enabled.
 149     */
 150    if (0 && ib && ctx->Extensions.ARB_draw_elements_base_vertex) {
 151       /* If we can just tell the hardware or the TNL to interpret our
 152        * indices with a different base, do so.
 153        */
 154       tmp_prims = malloc(sizeof(*prim) * nr_prims);
 155
 156       if (tmp_prims == NULL) {
 157          _mesa_error_no_memory(__func__);
 158          return;
 159       }
 160
 161       for (i = 0; i < nr_prims; i++) {
 162          tmp_prims[i] = prim[i];
 163          tmp_prims[i].basevertex -= min_index;
 164       }
 165
 166       prim = tmp_prims;
 167    } else if (ib) {
 168       /* Unfortunately need to adjust each index individually.
 169        */
 170       GLboolean map_ib = ib->obj->Name &&
 171                          !ib->obj->Mappings[MAP_INTERNAL].Pointer;
 172       void *ptr;
 173
 174       if (map_ib)
 175          ctx->Driver.MapBufferRange(ctx, 0, ib->obj->Size, GL_MAP_READ_BIT,
 176                                     ib->obj, MAP_INTERNAL);
 177
 178
 179       ptr = ADD_POINTERS(ib->obj->Mappings[MAP_INTERNAL].Pointer, ib->ptr);
 180
 181       /* Some users might prefer it if we translated elements to
 182        * GLuints here.  Others wouldn't...
 183        */
 184       switch (ib->type) {
 185       case GL_UNSIGNED_INT:
 186          tmp_indices = rebase_GLuint( ptr, ib->count, min_index );
 187          break;
 188       case GL_UNSIGNED_SHORT:
 189          tmp_indices = rebase_GLushort( ptr, ib->count, min_index );
 190          break;
 191       case GL_UNSIGNED_BYTE:
 192          tmp_indices = rebase_GLubyte( ptr, ib->count, min_index );
 193          break;
 194       }
 195
 196       if (map_ib)
 197          ctx->Driver.UnmapBuffer(ctx, ib->obj, MAP_INTERNAL);
 198
 199       if (tmp_indices == NULL) {
 200          return;
 201       }
 202
 203       tmp_ib.obj = ctx->Shared->NullBufferObj;
 204       tmp_ib.ptr = tmp_indices;
 205       tmp_ib.count = ib->count;
 206       tmp_ib.type = ib->type;
 207
 208       ib = &tmp_ib;
 209    }
 210    else {
 211       /* Otherwise the primitives need adjustment.
 212        */
 213       tmp_prims = malloc(sizeof(*prim) * nr_prims);
 214
 215       if (tmp_prims == NULL) {
 216          _mesa_error_no_memory(__func__);
 217          return;
 218       }
 219
 220       for (i = 0; i < nr_prims; i++) {
 221          /* If this fails, it could indicate an application error:
 222           */
 223          assert(prim[i].start >= min_index);
 224
 225          tmp_prims[i] = prim[i];
 226          tmp_prims[i].start -= min_index;
 227       }
 228
 229       prim = tmp_prims;
 230    }
 231
 232    /* Just need to adjust the pointer values on each incoming array.
 233     * This works for VBO and non-vbo rendering and shouldn't pesimize
 234     * VBO-based upload schemes.  However this may still not be a fast
 235     * path for hardware tnl for VBO based rendering as most machines
 236     * will be happier if you just specify a starting vertex value in
 237     * each primitive.
 238     *
 239     * For drivers with hardware tnl, you only want to do this if you
 240     * are forced to, eg non-VBO indexed rendering with start != 0.
 241     */
 242    for (i = 0; i < VERT_ATTRIB_MAX; i++) {
 243       tmp_arrays[i] = *arrays[i];
 244       tmp_arrays[i].Ptr += min_index * tmp_arrays[i].StrideB;
 245       tmp_array_pointers[i] = &tmp_arrays[i];
 246    }
 247
 248    /* Re-issue the draw call.
 249     */
 250    ctx->Array._DrawArrays = tmp_array_pointers;
 251    ctx->NewDriverState |= ctx->DriverFlags.NewArray;
 252
 253    draw( ctx,
 254          prim,
 255          nr_prims,
 256          ib,
 257          GL_TRUE,
 258          0,
 259          max_index - min_index,
 260          NULL, NULL );
 261
 262    ctx->Array._DrawArrays = saved_arrays;
 263    ctx->NewDriverState |= ctx->DriverFlags.NewArray;
 264
 265    free(tmp_indices);
 266
 267    free(tmp_prims);
 268 }
 269
 270
 271