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    tnl_draw_func draw;
  53
  54    const struct split_limits *limits;
  55    GLuint limit;
  56
  57    struct _mesa_prim dstprim[MAX_PRIM];
  58    GLuint dstprim_nr;
  59 };
  60
  61
  62
  63
  64 static void
  65 flush_vertex( struct split_context *split)
  66 {
  67    struct gl_context *ctx = split->ctx;
  68    struct _mesa_index_buffer ib;
  69    GLuint i;
  70
  71    if (!split->dstprim_nr)
  72       return;
  73
  74    if (split->ib) {
  75       ib = *split->ib;
  76
  77       ib.count = split->max_index - split->min_index + 1;
  78       ib.ptr = (const void *)((const char *)ib.ptr +
  79                               split->min_index * ib.index_size);
  80
  81       /* Rebase the primitives to save index buffer entries. */
  82       for (i = 0; i < split->dstprim_nr; i++)
  83          split->dstprim[i].start -= split->min_index;
  84    }
  85
  86    assert(split->max_index >= split->min_index);
  87
  88    split->draw(ctx,
  89                split->array,
  90                split->dstprim,
  91                split->dstprim_nr,
  92                split->ib ? &ib : NULL,
  93                !split->ib,
  94                split->min_index,
  95                split->max_index,
  96                NULL, 0, NULL);
  97
  98    split->dstprim_nr = 0;
  99    split->min_index = ~0;
 100    split->max_index = 0;
 101 }
 102
 103
 104 static struct _mesa_prim *
 105 next_outprim(struct split_context *split)
 106 {
 107    if (split->dstprim_nr == MAX_PRIM-1) {
 108       flush_vertex(split);
 109    }
 110
 111    {
 112       struct _mesa_prim *prim = &split->dstprim[split->dstprim_nr++];
 113       memset(prim, 0, sizeof(*prim));
 114       return prim;
 115    }
 116 }
 117
 118
 119 static void
 120 update_index_bounds(struct split_context *split,
 121                     const struct _mesa_prim *prim)
 122 {
 123    split->min_index = MIN2(split->min_index, prim->start);
 124    split->max_index = MAX2(split->max_index, prim->start + prim->count - 1);
 125 }
 126
 127
 128 /* Return the maximum amount of vertices that can be emitted for a
 129  * primitive starting at 'prim->start', depending on the previous
 130  * index bounds.
 131  */
 132 static GLuint
 133 get_max_vertices(struct split_context *split,
 134                  const struct _mesa_prim *prim)
 135 {
 136    if ((prim->start > split->min_index &&
 137         prim->start - split->min_index >= split->limit) ||
 138        (prim->start < split->max_index &&
 139         split->max_index - prim->start >= split->limit))
 140       /* "prim" starts too far away from the old range. */
 141       return 0;
 142
 143    return MIN2(split->min_index, prim->start) + split->limit - prim->start;
 144 }
 145
 146
 147 /* Break large primitives into smaller ones.  If not possible, convert
 148  * the primitive to indexed and pass to split_elts().
 149  */
 150 static void
 151 split_prims(struct split_context *split)
 152 {
 153    GLuint i;
 154
 155    for (i = 0; i < split->nr_prims; i++) {
 156       const struct _mesa_prim *prim = &split->prim[i];
 157       GLuint first, incr;
 158       GLboolean split_inplace =
 159          _tnl_split_prim_inplace(prim->mode, &first, &incr);
 160       GLuint available = get_max_vertices(split, prim);
 161       GLuint count = prim->count - (prim->count - first) % incr;
 162
 163       if (prim->count < first)
 164          continue;
 165
 166       if ((available < count && !split_inplace) ||
 167           (available < first && split_inplace)) {
 168          flush_vertex(split);
 169          available = get_max_vertices(split, prim);
 170       }
 171
 172       if (available >= count) {
 173          struct _mesa_prim *outprim = next_outprim(split);
 174
 175          *outprim = *prim;
 176          update_index_bounds(split, outprim);
 177       }
 178       else if (split_inplace) {
 179          GLuint j, nr;
 180
 181          for (j = 0 ; j < count ;) {
 182             GLuint remaining = count - j;
 183             struct _mesa_prim *outprim = next_outprim(split);
 184
 185             nr = MIN2(available, remaining);
 186             nr -= (nr - first) % incr;
 187
 188             outprim->mode = prim->mode;
 189             outprim->begin = (j == 0 && prim->begin);
 190             outprim->end = (nr == remaining && prim->end);
 191             outprim->start = prim->start + j;
 192             outprim->count = nr;
 193             outprim->num_instances = prim->num_instances;
 194             outprim->base_instance = prim->base_instance;
 195
 196             update_index_bounds(split, outprim);
 197
 198             if (nr == remaining) {
 199                /* Finished */
 200                j += nr;
 201             }
 202             else {
 203                /* Wrapped the primitive */
 204                j += nr - (first - incr);
 205                flush_vertex(split);
 206                available = get_max_vertices(split, prim);
 207             }
 208          }
 209       }
 210       else if (split->ib == NULL) {
 211          /* XXX: could at least send the first max_verts off from the
 212           * inplace buffers.
 213           */
 214
 215          /* else convert to indexed primitive and pass to split_elts,
 216           * which will do the necessary copying and turn it back into a
 217           * vertex primitive for rendering...
 218           */
 219          struct _mesa_index_buffer ib;
 220          struct _mesa_prim tmpprim;
 221          GLuint *elts = malloc(count * sizeof(GLuint));
 222          GLuint j;
 223
 224          for (j = 0; j < count; j++)
 225             elts[j] = prim->start + j;
 226
 227          ib.count = count;
 228          ib.index_size = 4;
 229          ib.obj = split->ctx->Shared->NullBufferObj;
 230          ib.ptr = elts;
 231
 232          tmpprim = *prim;
 233          tmpprim.indexed = 1;
 234          tmpprim.start = 0;
 235          tmpprim.count = count;
 236          tmpprim.num_instances = 1;
 237          tmpprim.base_instance = 0;
 238
 239          flush_vertex(split);
 240
 241          _tnl_split_copy(split->ctx,
 242                          split->array,
 243                          &tmpprim, 1,
 244                          &ib,
 245                          split->draw,
 246                          split->limits);
 247
 248          free(elts);
 249       }
 250       else {
 251          flush_vertex(split);
 252
 253          _tnl_split_copy(split->ctx,
 254                          split->array,
 255                          prim, 1,
 256                          split->ib,
 257                          split->draw,
 258                          split->limits);
 259       }
 260    }
 261
 262    flush_vertex(split);
 263 }
 264
 265
 266 void
 267 _tnl_split_inplace(struct gl_context *ctx,
 268                    const struct tnl_vertex_array *arrays,
 269                    const struct _mesa_prim *prim,
 270                    GLuint nr_prims,
 271                    const struct _mesa_index_buffer *ib,
 272                    GLuint min_index,
 273                    GLuint max_index,
 274                    tnl_draw_func draw,
 275                    const struct split_limits *limits)
 276 {
 277    struct split_context split;
 278
 279    memset(&split, 0, sizeof(split));
 280
 281    split.ctx = ctx;
 282    split.array = arrays;
 283    split.prim = prim;
 284    split.nr_prims = nr_prims;
 285    split.ib = ib;
 286
 287    /* Empty interval, makes calculations simpler. */
 288    split.min_index = ~0;
 289    split.max_index = 0;
 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 }
 297
 298