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 "main/glformats.h"
  34 #include "vbo_split.h"
  35
  36
  37 #define MAX_PRIM 32
  38
  39 /* Used for splitting without copying. No attempt is made to handle
  40  * too large indexed vertex buffers: In general you need to copy to do
  41  * that.
  42  */
  43 struct split_context {
  44    struct gl_context *ctx;
  45    const struct gl_client_array **array;
  46    const struct _mesa_prim *prim;
  47    GLuint nr_prims;
  48    const struct _mesa_index_buffer *ib;
  49    GLuint min_index;
  50    GLuint max_index;
  51    vbo_draw_func draw;
  52
  53    const struct split_limits *limits;
  54    GLuint limit;
  55
  56    struct _mesa_prim dstprim[MAX_PRIM];
  57    GLuint dstprim_nr;
  58 };
  59
  60
  61
  62
  63 static void flush_vertex( struct split_context *split )
  64 {
  65    struct gl_context *ctx = split->ctx;
  66    const struct gl_client_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 * _mesa_sizeof_type(ib.type));
  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, 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 *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 static void update_index_bounds(struct split_context *split,
 122                                 const struct _mesa_prim *prim)
 123 {
 124    split->min_index = MIN2(split->min_index, prim->start);
 125    split->max_index = MAX2(split->max_index, prim->start + prim->count - 1);
 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 get_max_vertices(struct split_context *split,
 133                                const struct _mesa_prim *prim)
 134 {
 135    if ((prim->start > split->min_index &&
 136         prim->start - split->min_index >= split->limit) ||
 137        (prim->start < split->max_index &&
 138         split->max_index - prim->start >= split->limit))
 139       /* "prim" starts too far away from the old range. */
 140       return 0;
 141
 142    return MIN2(split->min_index, prim->start) + split->limit - prim->start;
 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 split_prims( struct split_context *split)
 149 {
 150    GLuint i;
 151
 152    for (i = 0; i < split->nr_prims; i++) {
 153       const struct _mesa_prim *prim = &split->prim[i];
 154       GLuint first, incr;
 155       GLboolean split_inplace = split_prim_inplace(prim->mode, &first, &incr);
 156       GLuint available = get_max_vertices(split, prim);
 157       GLuint count = prim->count - (prim->count - first) % incr;
 158
 159       if (prim->count < first)
 160          continue;
 161
 162       if ((available < count && !split_inplace) ||
 163           (available < first && split_inplace)) {
 164          flush_vertex(split);
 165          available = get_max_vertices(split, prim);
 166       }
 167
 168       if (available >= count) {
 169          struct _mesa_prim *outprim = next_outprim(split);
 170
 171          *outprim = *prim;
 172          update_index_bounds(split, outprim);
 173       }
 174       else if (split_inplace) {
 175          GLuint j, nr;
 176
 177          for (j = 0 ; j < count ; ) {
 178             GLuint remaining = count - j;
 179             struct _mesa_prim *outprim = next_outprim(split);
 180
 181             nr = MIN2( available, remaining );
 182             nr -= (nr - first) % incr;
 183
 184             outprim->mode = prim->mode;
 185             outprim->begin = (j == 0 && prim->begin);
 186             outprim->end = (nr == remaining && prim->end);
 187             outprim->start = prim->start + j;
 188             outprim->count = nr;
 189             outprim->num_instances = prim->num_instances;
 190             outprim->base_instance = prim->base_instance;
 191
 192             update_index_bounds(split, outprim);
 193
 194             if (nr == remaining) {
 195                /* Finished.
 196                 */
 197                j += nr;
 198             }
 199             else {
 200                /* Wrapped the primitive:
 201                 */
 202                j += nr - (first - incr);
 203                flush_vertex(split);
 204                available = get_max_vertices(split, prim);
 205             }
 206          }
 207       }
 208       else if (split->ib == NULL) {
 209          /* XXX: could at least send the first max_verts off from the
 210           * inplace buffers.
 211           */
 212
 213          /* else convert to indexed primitive and pass to split_elts,
 214           * which will do the necessary copying and turn it back into a
 215           * vertex primitive for rendering...
 216           */
 217          struct _mesa_index_buffer ib;
 218          struct _mesa_prim tmpprim;
 219          GLuint *elts = malloc(count * sizeof(GLuint));
 220          GLuint j;
 221
 222          for (j = 0; j < count; j++)
 223             elts[j] = prim->start + j;
 224
 225          ib.count = count;
 226          ib.type = GL_UNSIGNED_INT;
 227          ib.obj = split->ctx->Shared->NullBufferObj;
 228          ib.ptr = elts;
 229
 230          tmpprim = *prim;
 231          tmpprim.indexed = 1;
 232          tmpprim.start = 0;
 233          tmpprim.count = count;
 234          tmpprim.num_instances = 1;
 235          tmpprim.base_instance = 0;
 236
 237          flush_vertex(split);
 238
 239          vbo_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          vbo_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 vbo_split_inplace( struct gl_context *ctx,
 265                         const struct gl_client_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