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/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
  54    vbo_exec_invalidate_state( ctx, ~0 );
  55 }
  56
  57
  58 void vbo_exec_destroy( struct gl_context *ctx )
  59 {
  60    struct vbo_exec_context *exec = &vbo_context(ctx)->exec;
  61
  62    if (ctx->aelt_context) {
  63       _ae_destroy_context( ctx );
  64       ctx->aelt_context = NULL;
  65    }
  66
  67    vbo_exec_vtx_destroy( exec );
  68 }
  69
  70
  71 /**
  72  * Really want to install these callbacks to a central facility to be
  73  * invoked according to the state flags.  That will have to wait for a
  74  * mesa rework:
  75  */
  76 void vbo_exec_invalidate_state( struct gl_context *ctx, GLuint new_state )
  77 {
  78    struct vbo_context *vbo = vbo_context(ctx);
  79    struct vbo_exec_context *exec = &vbo->exec;
  80
  81    if (!exec->validating && new_state & (_NEW_PROGRAM|_NEW_ARRAY)) {
  82       exec->array.recalculate_inputs = GL_TRUE;
  83    }
  84
  85    if (new_state & _NEW_EVAL)
  86       exec->eval.recalculate_maps = GL_TRUE;
  87
  88    _ae_invalidate_state(ctx, new_state);
  89 }
  90
  91
  92 /**
  93  * Figure out the number of transform feedback primitives that will be output
  94  * considering the drawing mode, number of vertices, and instance count,
  95  * assuming that no geometry shading is done and primitive restart is not
  96  * used.
  97  *
  98  * This is used by driver back-ends in implementing the PRIMITIVES_GENERATED
  99  * and TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN queries.  It is also used to
 100  * pre-validate draw calls in GLES3 (where draw calls only succeed if there is
 101  * enough room in the transform feedback buffer for the result).
 102  */
 103 size_t
 104 vbo_count_tessellated_primitives(GLenum mode, GLuint count,
 105                                  GLuint num_instances)
 106 {
 107    size_t num_primitives;
 108    switch (mode) {
 109    case GL_POINTS:
 110       num_primitives = count;
 111       break;
 112    case GL_LINE_STRIP:
 113       num_primitives = count >= 2 ? count - 1 : 0;
 114       break;
 115    case GL_LINE_LOOP:
 116       num_primitives = count >= 2 ? count : 0;
 117       break;
 118    case GL_LINES:
 119       num_primitives = count / 2;
 120       break;
 121    case GL_TRIANGLE_STRIP:
 122    case GL_TRIANGLE_FAN:
 123    case GL_POLYGON:
 124       num_primitives = count >= 3 ? count - 2 : 0;
 125       break;
 126    case GL_TRIANGLES:
 127       num_primitives = count / 3;
 128       break;
 129    case GL_QUAD_STRIP:
 130       num_primitives = count >= 4 ? ((count / 2) - 1) * 2 : 0;
 131       break;
 132    case GL_QUADS:
 133       num_primitives = (count / 4) * 2;
 134       break;
 135    case GL_LINES_ADJACENCY:
 136       num_primitives = count / 4;
 137       break;
 138    case GL_LINE_STRIP_ADJACENCY:
 139       num_primitives = count >= 4 ? count - 3 : 0;
 140       break;
 141    case GL_TRIANGLES_ADJACENCY:
 142       num_primitives = count / 6;
 143       break;
 144    case GL_TRIANGLE_STRIP_ADJACENCY:
 145       num_primitives = count >= 6 ? (count - 4) / 2 : 0;
 146       break;
 147    default:
 148       assert(!"Unexpected primitive type in count_tessellated_primitives");
 149       num_primitives = 0;
 150       break;
 151    }
 152    return num_primitives * num_instances;
 153 }
 154
 155
 156
 157 /**
 158  * In some degenarate cases we can improve our ability to merge
 159  * consecutive primitives.  For example:
 160  * glBegin(GL_LINE_STRIP);
 161  * glVertex(1);
 162  * glVertex(1);
 163  * glEnd();
 164  * glBegin(GL_LINE_STRIP);
 165  * glVertex(1);
 166  * glVertex(1);
 167  * glEnd();
 168  * Can be merged as a GL_LINES prim with four vertices.
 169  *
 170  * This function converts 2-vertex line strips/loops into GL_LINES, etc.
 171  */
 172 void
 173 vbo_try_prim_conversion(struct _mesa_prim *p)
 174 {
 175    if (p->mode == GL_LINE_STRIP && p->count == 2) {
 176       /* convert 2-vertex line strip to a separate line */
 177       p->mode = GL_LINES;
 178    }
 179    else if ((p->mode == GL_TRIANGLE_STRIP || p->mode == GL_TRIANGLE_FAN)
 180        && p->count == 3) {
 181       /* convert 3-vertex tri strip or fan to a separate triangle */
 182       p->mode = GL_TRIANGLES;
 183    }
 184
 185    /* Note: we can't convert a 4-vertex quad strip to a separate quad
 186     * because the vertex ordering is different.  We'd have to muck
 187     * around in the vertex data to make it work.
 188     */
 189 }
 190
 191
 192 /**
 193  * Helper function for determining if two subsequent glBegin/glEnd
 194  * primitives can be combined.  This is only possible for GL_POINTS,
 195  * GL_LINES, GL_TRIANGLES and GL_QUADS.
 196  * If we return true, it means that we can concatenate p1 onto p0 (and
 197  * discard p1).
 198  */
 199 bool
 200 vbo_can_merge_prims(const struct _mesa_prim *p0, const struct _mesa_prim *p1)
 201 {
 202    if (!p0->begin ||
 203        !p1->begin ||
 204        !p0->end ||
 205        !p1->end)
 206       return false;
 207
 208    /* The prim mode must match (ex: both GL_TRIANGLES) */
 209    if (p0->mode != p1->mode)
 210       return false;
 211
 212    /* p1's vertices must come right after p0 */
 213    if (p0->start + p0->count != p1->start)
 214       return false;
 215
 216    if (p0->basevertex != p1->basevertex ||
 217        p0->num_instances != p1->num_instances ||
 218        p0->base_instance != p1->base_instance)
 219       return false;
 220
 221    /* can always merge subsequent GL_POINTS primitives */
 222    if (p0->mode == GL_POINTS)
 223       return true;
 224
 225    /* independent lines with no extra vertices */
 226    if (p0->mode == GL_LINES && p0->count % 2 == 0 && p1->count % 2 == 0)
 227       return true;
 228
 229    /* independent tris */
 230    if (p0->mode == GL_TRIANGLES && p0->count % 3 == 0 && p1->count % 3 == 0)
 231       return true;
 232
 233    /* independent quads */
 234    if (p0->mode == GL_QUADS && p0->count % 4 == 0 && p1->count % 4 == 0)
 235       return true;
 236
 237    return false;
 238 }
 239
 240
 241 /**
 242  * If we've determined that p0 and p1 can be merged, this function
 243  * concatenates p1 onto p0.
 244  */
 245 void
 246 vbo_merge_prims(struct _mesa_prim *p0, const struct _mesa_prim *p1)
 247 {
 248    assert(vbo_can_merge_prims(p0, p1));
 249
 250    p0->count += p1->count;
 251    p0->end = p1->end;
 252 }