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