src/mesa/tnl/t_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/vbo.h"
  34
  35 #include "t_split.h"
  36
  37
  38 #define MAX_PRIM 32
  39
  40 /* Used for splitting without copying. No attempt is made to handle
  41  * too large indexed vertex buffers: In general you need to copy to do
  42  * that.
  43  */
  44 struct split_context {
  45    struct gl_context *ctx;
  46    const struct tnl_vertex_array *array;
  47    const struct _mesa_prim *prim;
  48    GLuint nr_prims;
  49    const struct _mesa_index_buffer *ib;
  50    GLuint min_index;
  51    GLuint max_index;
  52    GLuint num_instances;
  53    GLuint base_instance;
  54    tnl_draw_func draw;
  55
  56    const struct split_limits *limits;
  57    GLuint limit;
  58
  59    struct _mesa_prim dstprim[MAX_PRIM];
  60    GLuint dstprim_nr;
  61 };
  62
  63
  64
  65
  66 static void
  67 flush_vertex( struct split_context *split)
  68 {
  69    struct gl_context *ctx = split->ctx;
  70    struct _mesa_index_buffer ib;
  71    GLuint i;
  72
  73    if (!split->dstprim_nr)
  74       return;
  75
  76    if (split->ib) {
  77       ib = *split->ib;
  78
  79       ib.count = split->max_index - split->min_index + 1;
  80       ib.ptr = (const void *)((const char *)ib.ptr +
  81                               (split->min_index << ib.index_size_shift));
  82
  83       /* Rebase the primitives to save index buffer entries. */
  84       for (i = 0; i < split->dstprim_nr; i++)
  85          split->dstprim[i].start -= split->min_index;
  86    }
  87
  88    assert(split->max_index >= split->min_index);
  89
  90    split->draw(ctx,
  91                split->array,
  92                split->dstprim,
  93                split->dstprim_nr,
  94                split->ib ? &ib : NULL,
  95                !split->ib,
  96                split->min_index,
  97                split->max_index,
  98                split->num_instances,
  99                split->base_instance);
 100
 101    split->dstprim_nr = 0;
 102    split->min_index = ~0;
 103    split->max_index = 0;
 104 }
 105
 106
 107 static struct _mesa_prim *
 108 next_outprim(struct split_context *split)
 109 {
 110    if (split->dstprim_nr == MAX_PRIM-1) {
 111       flush_vertex(split);
 112    }
 113
 114    {
 115       struct _mesa_prim *prim = &split->dstprim[split->dstprim_nr++];
 116       memset(prim, 0, sizeof(*prim));
 117       return prim;
 118    }
 119 }
 120
 121
 122 static void
 123 update_index_bounds(struct split_context *split,
 124                     const struct _mesa_prim *prim)
 125 {
 126    split->min_index = MIN2(split->min_index, prim->start);
 127    split->max_index = MAX2(split->max_index, prim->start + prim->count - 1);
 128 }
 129
 130
 131 /* Return the maximum amount of vertices that can be emitted for a
 132  * primitive starting at 'prim->start', depending on the previous
 133  * index bounds.
 134  */
 135 static GLuint
 136 get_max_vertices(struct split_context *split,
 137                  const struct _mesa_prim *prim)
 138 {
 139    if ((prim->start > split->min_index &&
 140         prim->start - split->min_index >= split->limit) ||
 141        (prim->start < split->max_index &&
 142         split->max_index - prim->start >= split->limit))
 143       /* "prim" starts too far away from the old range. */
 144       return 0;
 145
 146    return MIN2(split->min_index, prim->start) + split->limit - prim->start;
 147 }
 148
 149
 150 /* Break large primitives into smaller ones.  If not possible, convert
 151  * the primitive to indexed and pass to split_elts().
 152  */
 153 static void
 154 split_prims(struct split_context *split)
 155 {
 156    GLuint i;
 157
 158    for (i = 0; i < split->nr_prims; i++) {
 159       const struct _mesa_prim *prim = &split->prim[i];
 160       GLuint first, incr;
 161       GLboolean split_inplace =
 162          _tnl_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
 197             update_index_bounds(split, outprim);
 198
 199             if (nr == remaining) {
 200                /* Finished */
 201                j += nr;
 202             }
 203             else {
 204                /* Wrapped the primitive */
 205                j += nr - (first - incr);
 206                flush_vertex(split);
 207                available = get_max_vertices(split, prim);
 208             }
 209          }
 210       }
 211       else if (split->ib == NULL) {
 212          /* XXX: could at least send the first max_verts off from the
 213           * inplace buffers.
 214           */
 215
 216          /* else convert to indexed primitive and pass to split_elts,
 217           * which will do the necessary copying and turn it back into a
 218           * vertex primitive for rendering...
 219           */
 220          struct _mesa_index_buffer ib;
 221          struct _mesa_prim tmpprim;
 222          GLuint *elts = malloc(count * sizeof(GLuint));
 223          GLuint j;
 224
 225          for (j = 0; j < count; j++)
 226             elts[j] = prim->start + j;
 227
 228          ib.count = count;
 229          ib.index_size_shift = 2;
 230          ib.obj = NULL;
 231          ib.ptr = elts;
 232
 233          tmpprim = *prim;
 234          tmpprim.start = 0;
 235          tmpprim.count = count;
 236
 237          flush_vertex(split);
 238
 239          _tnl_split_copy(split->ctx,
 240                          split->array,
 241                          &tmpprim, 1,
 242                          &ib,
 243                          split->draw,
 244                          split->limits);
 245
 246          free(elts);
 247       }
 248       else {
 249          flush_vertex(split);
 250
 251          _tnl_split_copy(split->ctx,
 252                          split->array,
 253                          prim, 1,
 254                          split->ib,
 255                          split->draw,
 256                          split->limits);
 257       }
 258    }
 259
 260    flush_vertex(split);
 261 }
 262
 263
 264 void
 265 _tnl_split_inplace(struct gl_context *ctx,
 266                    const struct tnl_vertex_array *arrays,
 267                    const struct _mesa_prim *prim,
 268                    GLuint nr_prims,
 269                    const struct _mesa_index_buffer *ib,
 270                    GLuint num_instances,
 271                    GLuint base_instance,
 272                    tnl_draw_func draw,
 273                    const struct split_limits *limits)
 274 {
 275    struct split_context split;
 276
 277    memset(&split, 0, sizeof(split));
 278
 279    split.ctx = ctx;
 280    split.array = arrays;
 281    split.prim = prim;
 282    split.nr_prims = nr_prims;
 283    split.ib = ib;
 284
 285    /* Empty interval, makes calculations simpler. */
 286    split.min_index = ~0;
 287    split.max_index = 0;
 288    split.num_instances = num_instances;
 289    split.base_instance = base_instance;
 290
 291    split.draw = draw;
 292    split.limits = limits;
 293    split.limit = ib ? limits->max_indices : limits->max_verts;
 294
 295    split_prims(&split);
 296 }