src/mesa/vbo/vbo_exec.c

   1 /*
   2  * Mesa 3-D graphics library
   3  *
   4  * Copyright (C) 1999-2005  Brian Paul   All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included
  14  * in all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  17  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  22  * OTHER DEALINGS IN THE SOFTWARE.
  23  *
  24  * Authors:
  25  *    Keith Whitwell <keith@tungstengraphics.com>
  26  */
  27
  28
  29 #include "main/api_arrayelt.h"
  30 #include "main/glheader.h"
  31 #include "main/mtypes.h"
  32 #include "main/vtxfmt.h"
  33 #include "vbo_context.h"
  34
  35
  36
  37 void vbo_exec_init( struct gl_context *ctx )
  38 {
  39    struct vbo_exec_context *exec = &vbo_context(ctx)->exec;
  40
  41    exec->ctx = ctx;
  42
  43    /* Initialize the arrayelt helper
  44     */
  45    if (!ctx->aelt_context &&
  46        !_ae_create_context( ctx ))
  47       return;
  48
  49    vbo_exec_vtx_init( exec );
  50
  51    ctx->Driver.NeedFlush = 0;
  52    ctx->Driver.CurrentExecPrimitive = PRIM_OUTSIDE_BEGIN_END;
  53    ctx->Driver.BeginVertices = vbo_exec_BeginVertices;
  54    ctx->Driver.FlushVertices = vbo_exec_FlushVertices;
  55
  56    vbo_exec_invalidate_state( ctx, ~0 );
  57 }
  58
  59
  60 void vbo_exec_destroy( struct gl_context *ctx )
  61 {
  62    struct vbo_exec_context *exec = &vbo_context(ctx)->exec;
  63
  64    if (ctx->aelt_context) {
  65       _ae_destroy_context( ctx );
  66       ctx->aelt_context = NULL;
  67    }
  68
  69    vbo_exec_vtx_destroy( exec );
  70 }
  71
  72
  73 /**
  74  * Really want to install these callbacks to a central facility to be
  75  * invoked according to the state flags.  That will have to wait for a
  76  * mesa rework:
  77  */
  78 void vbo_exec_invalidate_state( struct gl_context *ctx, GLuint new_state )
  79 {
  80    struct vbo_context *vbo = vbo_context(ctx);
  81    struct vbo_exec_context *exec = &vbo->exec;
  82
  83    if (!exec->validating && new_state & (_NEW_PROGRAM|_NEW_ARRAY)) {
  84       exec->array.recalculate_inputs = GL_TRUE;
  85
  86       /* If we ended up here because a VAO was deleted, the _DrawArrays
  87        * pointer which pointed to the VAO might be invalid now, so set it
  88        * to NULL.  This prevents crashes in driver functions like Clear
  89        * where driver state validation might occur, but the vbo module is
  90        * still in an invalid state.
  91        *
  92        * Drivers should skip vertex array state validation if _DrawArrays
  93        * is NULL.  It also has no effect on performance, because attrib
  94        * bindings will be recalculated anyway.
  95        */
  96       if (vbo->last_draw_method == DRAW_ARRAYS) {
  97          ctx->Array._DrawArrays = NULL;
  98          vbo->last_draw_method = DRAW_NONE;
  99       }
 100    }
 101
 102    if (new_state & _NEW_EVAL)
 103       exec->eval.recalculate_maps = 1;
 104
 105    _ae_invalidate_state(ctx, new_state);
 106 }
 107
 108
 109 /**
 110  * Figure out the number of transform feedback primitives that will be output
 111  * considering the drawing mode, number of vertices, and instance count,
 112  * assuming that no geometry shading is done and primitive restart is not
 113  * used.
 114  *
 115  * This is used by driver back-ends in implementing the PRIMITIVES_GENERATED
 116  * and TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN queries.  It is also used to
 117  * pre-validate draw calls in GLES3 (where draw calls only succeed if there is
 118  * enough room in the transform feedback buffer for the result).
 119  */
 120 size_t
 121 vbo_count_tessellated_primitives(GLenum mode, GLuint count,
 122                                  GLuint num_instances)
 123 {
 124    size_t num_primitives;
 125    switch (mode) {
 126    case GL_POINTS:
 127       num_primitives = count;
 128       break;
 129    case GL_LINE_STRIP:
 130       num_primitives = count >= 2 ? count - 1 : 0;
 131       break;
 132    case GL_LINE_LOOP:
 133       num_primitives = count >= 2 ? count : 0;
 134       break;
 135    case GL_LINES:
 136       num_primitives = count / 2;
 137       break;
 138    case GL_TRIANGLE_STRIP:
 139    case GL_TRIANGLE_FAN:
 140    case GL_POLYGON:
 141       num_primitives = count >= 3 ? count - 2 : 0;
 142       break;
 143    case GL_TRIANGLES:
 144       num_primitives = count / 3;
 145       break;
 146    case GL_QUAD_STRIP:
 147       num_primitives = count >= 4 ? ((count / 2) - 1) * 2 : 0;
 148       break;
 149    case GL_QUADS:
 150       num_primitives = (count / 4) * 2;
 151       break;
 152    default:
 153       assert(!"Unexpected primitive type in count_tessellated_primitives");
 154       num_primitives = 0;
 155       break;
 156    }
 157    return num_primitives * num_instances;
 158 }
 159
 160
 161
 162 /**
 163  * In some degenarate cases we can improve our ability to merge
 164  * consecutive primitives.  For example:
 165  * glBegin(GL_LINE_STRIP);
 166  * glVertex(1);
 167  * glVertex(1);
 168  * glEnd();
 169  * glBegin(GL_LINE_STRIP);
 170  * glVertex(1);
 171  * glVertex(1);
 172  * glEnd();
 173  * Can be merged as a GL_LINES prim with four vertices.
 174  *
 175  * This function converts 2-vertex line strips/loops into GL_LINES, etc.
 176  */
 177 void
 178 vbo_try_prim_conversion(struct _mesa_prim *p)
 179 {
 180    if (p->mode == GL_LINE_STRIP && p->count == 2) {
 181       /* convert 2-vertex line strip to a separate line */
 182       p->mode = GL_LINES;
 183    }
 184    else if ((p->mode == GL_TRIANGLE_STRIP || p->mode == GL_TRIANGLE_FAN)
 185        && p->count == 3) {
 186       /* convert 3-vertex tri strip or fan to a separate triangle */
 187       p->mode = GL_TRIANGLES;
 188    }
 189
 190    /* Note: we can't convert a 4-vertex quad strip to a separate quad
 191     * because the vertex ordering is different.  We'd have to muck
 192     * around in the vertex data to make it work.
 193     */
 194 }
 195
 196
 197 /**
 198  * Helper function for determining if two subsequent glBegin/glEnd
 199  * primitives can be combined.  This is only possible for GL_POINTS,
 200  * GL_LINES, GL_TRIANGLES and GL_QUADS.
 201  * If we return true, it means that we can concatenate p1 onto p0 (and
 202  * discard p1).
 203  */
 204 bool
 205 vbo_can_merge_prims(const struct _mesa_prim *p0, const struct _mesa_prim *p1)
 206 {
 207    if (!p0->begin ||
 208        !p1->begin ||
 209        !p0->end ||
 210        !p1->end)
 211       return false;
 212
 213    /* The prim mode must match (ex: both GL_TRIANGLES) */
 214    if (p0->mode != p1->mode)
 215       return false;
 216
 217    /* p1's vertices must come right after p0 */
 218    if (p0->start + p0->count != p1->start)
 219       return false;
 220
 221    if (p0->basevertex != p1->basevertex ||
 222        p0->num_instances != p1->num_instances ||
 223        p0->base_instance != p1->base_instance)
 224       return false;
 225
 226    /* can always merge subsequent GL_POINTS primitives */
 227    if (p0->mode == GL_POINTS)
 228       return true;
 229
 230    /* independent lines with no extra vertices */
 231    if (p0->mode == GL_LINES && p0->count % 2 == 0 && p1->count % 2 == 0)
 232       return true;
 233
 234    /* independent tris */
 235    if (p0->mode == GL_TRIANGLES && p0->count % 3 == 0 && p1->count % 3 == 0)
 236       return true;
 237
 238    /* independent quads */
 239    if (p0->mode == GL_QUADS && p0->count % 4 == 0 && p1->count % 4 == 0)
 240       return true;
 241
 242    return false;
 243 }
 244
 245
 246 /**
 247  * If we've determined that p0 and p1 can be merged, this function
 248  * concatenates p1 onto p0.
 249  */
 250 void
 251 vbo_merge_prims(struct _mesa_prim *p0, const struct _mesa_prim *p1)
 252 {
 253    assert(vbo_can_merge_prims(p0, p1));
 254
 255    p0->count += p1->count;
 256    p0->end = p1->end;
 257 }