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    const struct gl_vertex_array **saved_arrays = ctx->Array._DrawArrays;
  67    struct _mesa_index_buffer ib;
  68    GLuint i;
  69
  70    if (!split->dstprim_nr)
  71       return;
  72
  73    if (split->ib) {
  74       ib = *split->ib;
  75
  76       ib.count = split->max_index - split->min_index + 1;
  77       ib.ptr = (const void *)((const char *)ib.ptr +
  78                               split->min_index * ib.index_size);
  79
  80       /* Rebase the primitives to save index buffer entries. */
  81       for (i = 0; i < split->dstprim_nr; i++)
  82          split->dstprim[i].start -= split->min_index;
  83    }
  84
  85    assert(split->max_index >= split->min_index);
  86
  87    ctx->Array._DrawArrays = split->array;
  88    ctx->NewDriverState |= ctx->DriverFlags.NewArray;
  89
  90    split->draw(ctx,
  91                split->dstprim,
  92                split->dstprim_nr,
  93                split->ib ? &ib : NULL,
  94                !split->ib,
  95                split->min_index,
  96                split->max_index,
  97                NULL, 0, NULL);
  98
  99    ctx->Array._DrawArrays = saved_arrays;
 100    ctx->NewDriverState |= ctx->DriverFlags.NewArray;
 101
 102    split->dstprim_nr = 0;
 103    split->min_index = ~0;
 104    split->max_index = 0;
 105 }
 106
 107
 108 static struct _mesa_prim *
 109 next_outprim(struct split_context *split)
 110 {
 111    if (split->dstprim_nr == MAX_PRIM-1) {
 112       flush_vertex(split);
 113    }
 114
 115    {
 116       struct _mesa_prim *prim = &split->dstprim[split->dstprim_nr++];
 117       memset(prim, 0, sizeof(*prim));
 118       return prim;
 119    }
 120 }
 121
 122
 123 static void
 124 update_index_bounds(struct split_context *split,
 125                     const struct _mesa_prim *prim)
 126 {
 127    split->min_index = MIN2(split->min_index, prim->start);
 128    split->max_index = MAX2(split->max_index, prim->start + prim->count - 1);
 129 }
 130
 131
 132 /* Return the maximum amount of vertices that can be emitted for a
 133  * primitive starting at 'prim->start', depending on the previous
 134  * index bounds.
 135  */
 136 static GLuint
 137 get_max_vertices(struct split_context *split,
 138                  const struct _mesa_prim *prim)
 139 {
 140    if ((prim->start > split->min_index &&
 141         prim->start - split->min_index >= split->limit) ||
 142        (prim->start < split->max_index &&
 143         split->max_index - prim->start >= split->limit))
 144       /* "prim" starts too far away from the old range. */
 145       return 0;
 146
 147    return MIN2(split->min_index, prim->start) + split->limit - prim->start;
 148 }
 149
 150
 151 /* Break large primitives into smaller ones.  If not possible, convert
 152  * the primitive to indexed and pass to split_elts().
 153  */
 154 static void
 155 split_prims(struct split_context *split)
 156 {
 157    GLuint i;
 158
 159    for (i = 0; i < split->nr_prims; i++) {
 160       const struct _mesa_prim *prim = &split->prim[i];
 161       GLuint first, incr;
 162       GLboolean split_inplace = split_prim_inplace(prim->mode, &first, &incr);
 163       GLuint available = get_max_vertices(split, prim);
 164       GLuint count = prim->count - (prim->count - first) % incr;
 165
 166       if (prim->count < first)
 167          continue;
 168
 169       if ((available < count && !split_inplace) ||
 170           (available < first && split_inplace)) {
 171          flush_vertex(split);
 172          available = get_max_vertices(split, prim);
 173       }
 174
 175       if (available >= count) {
 176          struct _mesa_prim *outprim = next_outprim(split);
 177
 178          *outprim = *prim;
 179          update_index_bounds(split, outprim);
 180       }
 181       else if (split_inplace) {
 182          GLuint j, nr;
 183
 184          for (j = 0 ; j < count ;) {
 185             GLuint remaining = count - j;
 186             struct _mesa_prim *outprim = next_outprim(split);
 187
 188             nr = MIN2(available, remaining);
 189             nr -= (nr - first) % incr;
 190
 191             outprim->mode = prim->mode;
 192             outprim->begin = (j == 0 && prim->begin);
 193             outprim->end = (nr == remaining && prim->end);
 194             outprim->start = prim->start + j;
 195             outprim->count = nr;
 196             outprim->num_instances = prim->num_instances;
 197             outprim->base_instance = prim->base_instance;
 198
 199             update_index_bounds(split, outprim);
 200
 201             if (nr == remaining) {
 202                /* Finished */
 203                j += nr;
 204             }
 205             else {
 206                /* Wrapped the primitive */
 207                j += nr - (first - incr);
 208                flush_vertex(split);
 209                available = get_max_vertices(split, prim);
 210             }
 211          }
 212       }
 213       else if (split->ib == NULL) {
 214          /* XXX: could at least send the first max_verts off from the
 215           * inplace buffers.
 216           */
 217
 218          /* else convert to indexed primitive and pass to split_elts,
 219           * which will do the necessary copying and turn it back into a
 220           * vertex primitive for rendering...
 221           */
 222          struct _mesa_index_buffer ib;
 223          struct _mesa_prim tmpprim;
 224          GLuint *elts = malloc(count * sizeof(GLuint));
 225          GLuint j;
 226
 227          for (j = 0; j < count; j++)
 228             elts[j] = prim->start + j;
 229
 230          ib.count = count;
 231          ib.index_size = 4;
 232          ib.obj = split->ctx->Shared->NullBufferObj;
 233          ib.ptr = elts;
 234
 235          tmpprim = *prim;
 236          tmpprim.indexed = 1;
 237          tmpprim.start = 0;
 238          tmpprim.count = count;
 239          tmpprim.num_instances = 1;
 240          tmpprim.base_instance = 0;
 241
 242          flush_vertex(split);
 243
 244          vbo_split_copy(split->ctx,
 245                         split->array,
 246                         &tmpprim, 1,
 247                         &ib,
 248                         split->draw,
 249                         split->limits);
 250
 251          free(elts);
 252       }
 253       else {
 254          flush_vertex(split);
 255
 256          vbo_split_copy(split->ctx,
 257                         split->array,
 258                         prim, 1,
 259                         split->ib,
 260                         split->draw,
 261                         split->limits);
 262       }
 263    }
 264
 265    flush_vertex(split);
 266 }
 267
 268
 269 void
 270 vbo_split_inplace(struct gl_context *ctx,
 271                   const struct gl_vertex_array *arrays[],
 272                   const struct _mesa_prim *prim,
 273                   GLuint nr_prims,
 274                   const struct _mesa_index_buffer *ib,
 275                   GLuint min_index,
 276                   GLuint max_index,
 277                   vbo_draw_func draw,
 278                   const struct split_limits *limits)
 279 {
 280    struct split_context split;
 281
 282    memset(&split, 0, sizeof(split));
 283
 284    split.ctx = ctx;
 285    split.array = arrays;
 286    split.prim = prim;
 287    split.nr_prims = nr_prims;
 288    split.ib = ib;
 289
 290    /* Empty interval, makes calculations simpler. */
 291    split.min_index = ~0;
 292    split.max_index = 0;
 293
 294    split.draw = draw;
 295    split.limits = limits;
 296    split.limit = ib ? limits->max_indices : limits->max_verts;
 297
 298    split_prims(&split);
 299 }
 300
 301