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 <keithw@vmware.com>
  26  */
  27
  28
  29 #include "main/glheader.h"
  30 #include "main/mtypes.h"
  31 #include "main/vtxfmt.h"
  32 #include "vbo_context.h"
  33
  34
  35
  36 void
  37 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    /* aelt_context should have been created by the caller */
  44    assert(ctx->aelt_context);
  45
  46    vbo_exec_vtx_init(exec);
  47
  48    ctx->Driver.NeedFlush = 0;
  49    ctx->Driver.CurrentExecPrimitive = PRIM_OUTSIDE_BEGIN_END;
  50
  51    /* The aelt_context state should still be dirty from its creation */
  52    assert(_ae_is_state_dirty(ctx));
  53
  54    exec->array.recalculate_inputs = GL_TRUE;
  55    exec->eval.recalculate_maps = GL_TRUE;
  56 }
  57
  58
  59 void vbo_exec_destroy( struct gl_context *ctx )
  60 {
  61    struct vbo_exec_context *exec = &vbo_context(ctx)->exec;
  62
  63    if (ctx->aelt_context) {
  64       _ae_destroy_context( ctx );
  65       ctx->aelt_context = NULL;
  66    }
  67
  68    vbo_exec_vtx_destroy( exec );
  69 }
  70
  71
  72 /**
  73  * In some degenarate cases we can improve our ability to merge
  74  * consecutive primitives.  For example:
  75  * glBegin(GL_LINE_STRIP);
  76  * glVertex(1);
  77  * glVertex(1);
  78  * glEnd();
  79  * glBegin(GL_LINE_STRIP);
  80  * glVertex(1);
  81  * glVertex(1);
  82  * glEnd();
  83  * Can be merged as a GL_LINES prim with four vertices.
  84  *
  85  * This function converts 2-vertex line strips/loops into GL_LINES, etc.
  86  */
  87 void
  88 vbo_try_prim_conversion(struct _mesa_prim *p)
  89 {
  90    if (p->mode == GL_LINE_STRIP && p->count == 2) {
  91       /* convert 2-vertex line strip to a separate line */
  92       p->mode = GL_LINES;
  93    }
  94    else if ((p->mode == GL_TRIANGLE_STRIP || p->mode == GL_TRIANGLE_FAN)
  95        && p->count == 3) {
  96       /* convert 3-vertex tri strip or fan to a separate triangle */
  97       p->mode = GL_TRIANGLES;
  98    }
  99
 100    /* Note: we can't convert a 4-vertex quad strip to a separate quad
 101     * because the vertex ordering is different.  We'd have to muck
 102     * around in the vertex data to make it work.
 103     */
 104 }
 105
 106
 107 /**
 108  * Helper function for determining if two subsequent glBegin/glEnd
 109  * primitives can be combined.  This is only possible for GL_POINTS,
 110  * GL_LINES, GL_TRIANGLES and GL_QUADS.
 111  * If we return true, it means that we can concatenate p1 onto p0 (and
 112  * discard p1).
 113  */
 114 bool
 115 vbo_can_merge_prims(const struct _mesa_prim *p0, const struct _mesa_prim *p1)
 116 {
 117    if (!p0->begin ||
 118        !p1->begin ||
 119        !p0->end ||
 120        !p1->end)
 121       return false;
 122
 123    /* The prim mode must match (ex: both GL_TRIANGLES) */
 124    if (p0->mode != p1->mode)
 125       return false;
 126
 127    /* p1's vertices must come right after p0 */
 128    if (p0->start + p0->count != p1->start)
 129       return false;
 130
 131    if (p0->basevertex != p1->basevertex ||
 132        p0->num_instances != p1->num_instances ||
 133        p0->base_instance != p1->base_instance)
 134       return false;
 135
 136    /* can always merge subsequent GL_POINTS primitives */
 137    if (p0->mode == GL_POINTS)
 138       return true;
 139
 140    /* independent lines with no extra vertices */
 141    if (p0->mode == GL_LINES && p0->count % 2 == 0 && p1->count % 2 == 0)
 142       return true;
 143
 144    /* independent tris */
 145    if (p0->mode == GL_TRIANGLES && p0->count % 3 == 0 && p1->count % 3 == 0)
 146       return true;
 147
 148    /* independent quads */
 149    if (p0->mode == GL_QUADS && p0->count % 4 == 0 && p1->count % 4 == 0)
 150       return true;
 151
 152    return false;
 153 }
 154
 155
 156 /**
 157  * If we've determined that p0 and p1 can be merged, this function
 158  * concatenates p1 onto p0.
 159  */
 160 void
 161 vbo_merge_prims(struct _mesa_prim *p0, const struct _mesa_prim *p1)
 162 {
 163    assert(vbo_can_merge_prims(p0, p1));
 164
 165    p0->count += p1->count;
 166    p0->end = p1->end;
 167 }