src/mesa/vbo/vbo_split_inplace.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
  30 #include "main/mtypes.h"
  31 #include "main/macros.h"
  32 #include "main/enums.h"
  33 #include "vbo_split.h"
  34
  35
  36 #define MAX_PRIM 32
  37
  38 /* Used for splitting without copying. No attempt is made to handle
  39  * too large indexed vertex buffers: In general you need to copy to do
  40  * that.
  41  */
  42 struct split_context {
  43    struct gl_context *ctx;
  44    const struct gl_vertex_array *array;
  45    const struct _mesa_prim *prim;
  46    GLuint nr_prims;
  47    const struct _mesa_index_buffer *ib;
  48    GLuint min_index;
  49    GLuint max_index;
  50    vbo_draw_func draw;
  51
  52    const struct split_limits *limits;
  53    GLuint limit;
  54
  55    struct _mesa_prim dstprim[MAX_PRIM];
  56    GLuint dstprim_nr;
  57 };
  58
  59
  60
  61
  62 static void
  63 flush_vertex( struct split_context *split)
  64 {
  65    struct gl_context *ctx = split->ctx;
  66    struct _mesa_index_buffer ib;
  67    GLuint i;
  68
  69    if (!split->dstprim_nr)
  70       return;
  71
  72    if (split->ib) {
  73       ib = *split->ib;
  74
  75       ib.count = split->max_index - split->min_index + 1;
  76       ib.ptr = (const void *)((const char *)ib.ptr +
  77                               split->min_index * ib.index_size);
  78
  79       /* Rebase the primitives to save index buffer entries. */
  80       for (i = 0; i < split->dstprim_nr; i++)
  81          split->dstprim[i].start -= split->min_index;
  82    }
  83
  84    assert(split->max_index >= split->min_index);
  85
  86    split->draw(ctx,
  87                split->array,
  88                split->dstprim,
  89                split->dstprim_nr,
  90                split->ib ? &ib : NULL,
  91                !split->ib,
  92                split->min_index,
  93                split->max_index,
  94                NULL, 0, NULL);
  95
  96    split->dstprim_nr = 0;
  97    split->min_index = ~0;
  98    split->max_index = 0;
  99 }
 100
 101
 102 static struct _mesa_prim *
 103 next_outprim(struct split_context *split)
 104 {
 105    if (split->dstprim_nr == MAX_PRIM-1) {
 106       flush_vertex(split);
 107    }
 108
 109    {
 110       struct _mesa_prim *prim = &split->dstprim[split->dstprim_nr++];
 111       memset(prim, 0, sizeof(*prim));
 112       return prim;
 113    }
 114 }
 115
 116
 117 static void
 118 update_index_bounds(struct split_context *split,
 119                     const struct _mesa_prim *prim)
 120 {
 121    split->min_index = MIN2(split->min_index, prim->start);
 122    split->max_index = MAX2(split->max_index, prim->start + prim->count - 1);
 123 }
 124
 125
 126 /* Return the maximum amount of vertices that can be emitted for a
 127  * primitive starting at 'prim->start', depending on the previous
 128  * index bounds.
 129  */
 130 static GLuint
 131 get_max_vertices(struct split_context *split,
 132                  const struct _mesa_prim *prim)
 133 {
 134    if ((prim->start > split->min_index &&
 135         prim->start - split->min_index >= split->limit) ||
 136        (prim->start < split->max_index &&
 137         split->max_index - prim->start >= split->limit))
 138       /* "prim" starts too far away from the old range. */
 139       return 0;
 140
 141    return MIN2(split->min_index, prim->start) + split->limit - prim->start;
 142 }
 143
 144
 145 /* Break large primitives into smaller ones.  If not possible, convert
 146  * the primitive to indexed and pass to split_elts().
 147  */
 148 static void
 149 split_prims(struct split_context *split)
 150 {
 151    GLuint i;
 152
 153    for (i = 0; i < split->nr_prims; i++) {
 154       const struct _mesa_prim *prim = &split->prim[i];
 155       GLuint first, incr;
 156       GLboolean split_inplace = split_prim_inplace(prim->mode, &first, &incr);
 157       GLuint available = get_max_vertices(split, prim);
 158       GLuint count = prim->count - (prim->count - first) % incr;
 159
 160       if (prim->count < first)
 161          continue;
 162
 163       if ((available < count && !split_inplace) ||
 164           (available < first && split_inplace)) {
 165          flush_vertex(split);
 166          available = get_max_vertices(split, prim);
 167       }
 168
 169       if (available >= count) {
 170          struct _mesa_prim *outprim = next_outprim(split);
 171
 172          *outprim = *prim;
 173          update_index_bounds(split, outprim);
 174       }
 175       else if (split_inplace) {
 176          GLuint j, nr;
 177
 178          for (j = 0 ; j < count ;) {
 179             GLuint remaining = count - j;
 180             struct _mesa_prim *outprim = next_outprim(split);
 181
 182             nr = MIN2(available, remaining);
 183             nr -= (nr - first) % incr;
 184
 185             outprim->mode = prim->mode;
 186             outprim->begin = (j == 0 && prim->begin);
 187             outprim->end = (nr == remaining && prim->end);
 188             outprim->start = prim->start + j;
 189             outprim->count = nr;
 190             outprim->num_instances = prim->num_instances;
 191             outprim->base_instance = prim->base_instance;
 192
 193             update_index_bounds(split, outprim);
 194
 195             if (nr == remaining) {
 196                /* Finished */
 197                j += nr;
 198             }
 199             else {
 200                /* Wrapped the primitive */
 201                j += nr - (first - incr);
 202                flush_vertex(split);
 203                available = get_max_vertices(split, prim);
 204             }
 205          }
 206       }
 207       else if (split->ib == NULL) {
 208          /* XXX: could at least send the first max_verts off from the
 209           * inplace buffers.
 210           */
 211
 212          /* else convert to indexed primitive and pass to split_elts,
 213           * which will do the necessary copying and turn it back into a
 214           * vertex primitive for rendering...
 215           */
 216          struct _mesa_index_buffer ib;
 217          struct _mesa_prim tmpprim;
 218          GLuint *elts = malloc(count * sizeof(GLuint));
 219          GLuint j;
 220
 221          for (j = 0; j < count; j++)
 222             elts[j] = prim->start + j;
 223
 224          ib.count = count;
 225          ib.index_size = 4;
 226          ib.obj = split->ctx->Shared->NullBufferObj;
 227          ib.ptr = elts;
 228
 229          tmpprim = *prim;
 230          tmpprim.indexed = 1;
 231          tmpprim.start = 0;
 232          tmpprim.count = count;
 233          tmpprim.num_instances = 1;
 234          tmpprim.base_instance = 0;
 235
 236          flush_vertex(split);
 237
 238          vbo_split_copy(split->ctx,
 239                         split->array,
 240                         &tmpprim, 1,
 241                         &ib,
 242                         split->draw,
 243                         split->limits);
 244
 245          free(elts);
 246       }
 247       else {
 248          flush_vertex(split);
 249
 250          vbo_split_copy(split->ctx,
 251                         split->array,
 252                         prim, 1,
 253                         split->ib,
 254                         split->draw,
 255                         split->limits);
 256       }
 257    }
 258
 259    flush_vertex(split);
 260 }
 261
 262
 263 void
 264 vbo_split_inplace(struct gl_context *ctx,
 265                   const struct gl_vertex_array *arrays,
 266                   const struct _mesa_prim *prim,
 267                   GLuint nr_prims,
 268                   const struct _mesa_index_buffer *ib,
 269                   GLuint min_index,
 270                   GLuint max_index,
 271                   vbo_draw_func draw,
 272                   const struct split_limits *limits)
 273 {
 274    struct split_context split;
 275
 276    memset(&split, 0, sizeof(split));
 277
 278    split.ctx = ctx;
 279    split.array = arrays;
 280    split.prim = prim;
 281    split.nr_prims = nr_prims;
 282    split.ib = ib;
 283
 284    /* Empty interval, makes calculations simpler. */
 285    split.min_index = ~0;
 286    split.max_index = 0;
 287
 288    split.draw = draw;
 289    split.limits = limits;
 290    split.limit = ib ? limits->max_indices : limits->max_verts;
 291
 292    split_prims(&split);
 293 }
 294
 295