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/api_arrayelt.h"
  32 #include "main/vtxfmt.h"
  33 #include "vbo_private.h"
  34
  35
  36
  37 void
  38 vbo_exec_init(struct gl_context *ctx)
  39 {
  40    struct vbo_exec_context *exec = &vbo_context(ctx)->exec;
  41
  42    exec->ctx = ctx;
  43
  44    /* aelt_context should have been created by the caller */
  45    assert(ctx->aelt_context);
  46
  47    vbo_exec_vtx_init(exec);
  48
  49    ctx->Driver.NeedFlush = 0;
  50    ctx->Driver.CurrentExecPrimitive = PRIM_OUTSIDE_BEGIN_END;
  51
  52    /* The aelt_context state should still be dirty from its creation */
  53    assert(_ae_is_state_dirty(ctx));
  54
  55    exec->array.recalculate_inputs = GL_TRUE;
  56    exec->eval.recalculate_maps = GL_TRUE;
  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  * In some degenarate cases we can improve our ability to merge
  75  * consecutive primitives.  For example:
  76  * glBegin(GL_LINE_STRIP);
  77  * glVertex(1);
  78  * glVertex(1);
  79  * glEnd();
  80  * glBegin(GL_LINE_STRIP);
  81  * glVertex(1);
  82  * glVertex(1);
  83  * glEnd();
  84  * Can be merged as a GL_LINES prim with four vertices.
  85  *
  86  * This function converts 2-vertex line strips/loops into GL_LINES, etc.
  87  */
  88 void
  89 vbo_try_prim_conversion(struct _mesa_prim *p)
  90 {
  91    if (p->mode == GL_LINE_STRIP && p->count == 2) {
  92       /* convert 2-vertex line strip to a separate line */
  93       p->mode = GL_LINES;
  94    }
  95    else if ((p->mode == GL_TRIANGLE_STRIP || p->mode == GL_TRIANGLE_FAN)
  96        && p->count == 3) {
  97       /* convert 3-vertex tri strip or fan to a separate triangle */
  98       p->mode = GL_TRIANGLES;
  99    }
 100
 101    /* Note: we can't convert a 4-vertex quad strip to a separate quad
 102     * because the vertex ordering is different.  We'd have to muck
 103     * around in the vertex data to make it work.
 104     */
 105 }
 106
 107
 108 /**
 109  * Helper function for determining if two subsequent glBegin/glEnd
 110  * primitives can be combined.  This is only possible for GL_POINTS,
 111  * GL_LINES, GL_TRIANGLES and GL_QUADS.
 112  * If we return true, it means that we can concatenate p1 onto p0 (and
 113  * discard p1).
 114  */
 115 bool
 116 vbo_can_merge_prims(const struct _mesa_prim *p0, const struct _mesa_prim *p1)
 117 {
 118    if (!p0->begin ||
 119        !p1->begin ||
 120        !p0->end ||
 121        !p1->end)
 122       return false;
 123
 124    /* The prim mode must match (ex: both GL_TRIANGLES) */
 125    if (p0->mode != p1->mode)
 126       return false;
 127
 128    /* p1's vertices must come right after p0 */
 129    if (p0->start + p0->count != p1->start)
 130       return false;
 131
 132    if (p0->basevertex != p1->basevertex ||
 133        p0->num_instances != p1->num_instances ||
 134        p0->base_instance != p1->base_instance)
 135       return false;
 136
 137    /* can always merge subsequent GL_POINTS primitives */
 138    if (p0->mode == GL_POINTS)
 139       return true;
 140
 141    /* independent lines with no extra vertices */
 142    if (p0->mode == GL_LINES && p0->count % 2 == 0 && p1->count % 2 == 0)
 143       return true;
 144
 145    /* independent tris */
 146    if (p0->mode == GL_TRIANGLES && p0->count % 3 == 0 && p1->count % 3 == 0)
 147       return true;
 148
 149    /* independent quads */
 150    if (p0->mode == GL_QUADS && p0->count % 4 == 0 && p1->count % 4 == 0)
 151       return true;
 152
 153    return false;
 154 }
 155
 156
 157 /**
 158  * If we've determined that p0 and p1 can be merged, this function
 159  * concatenates p1 onto p0.
 160  */
 161 void
 162 vbo_merge_prims(struct _mesa_prim *p0, const struct _mesa_prim *p1)
 163 {
 164    assert(vbo_can_merge_prims(p0, p1));
 165
 166    p0->count += p1->count;
 167    p0->end = p1->end;
 168 }