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
  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  * 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, GLbitfield 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
  87    if (new_state & _NEW_EVAL)
  88       exec->eval.recalculate_maps = GL_TRUE;
  89
  90    _ae_invalidate_state(ctx, new_state);
  91 }
  92
  93
  94 /**
  95  * Figure out the number of transform feedback primitives that will be output
  96  * considering the drawing mode, number of vertices, and instance count,
  97  * assuming that no geometry shading is done and primitive restart is not
  98  * used.
  99  *
 100  * This is used by driver back-ends in implementing the PRIMITIVES_GENERATED
 101  * and TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN queries.  It is also used to
 102  * pre-validate draw calls in GLES3 (where draw calls only succeed if there is
 103  * enough room in the transform feedback buffer for the result).
 104  */
 105 size_t
 106 vbo_count_tessellated_primitives(GLenum mode, GLuint count,
 107                                  GLuint num_instances)
 108 {
 109    size_t num_primitives;
 110    switch (mode) {
 111    case GL_POINTS:
 112       num_primitives = count;
 113       break;
 114    case GL_LINE_STRIP:
 115       num_primitives = count >= 2 ? count - 1 : 0;
 116       break;
 117    case GL_LINE_LOOP:
 118       num_primitives = count >= 2 ? count : 0;
 119       break;
 120    case GL_LINES:
 121       num_primitives = count / 2;
 122       break;
 123    case GL_TRIANGLE_STRIP:
 124    case GL_TRIANGLE_FAN:
 125    case GL_POLYGON:
 126       num_primitives = count >= 3 ? count - 2 : 0;
 127       break;
 128    case GL_TRIANGLES:
 129       num_primitives = count / 3;
 130       break;
 131    case GL_QUAD_STRIP:
 132       num_primitives = count >= 4 ? ((count / 2) - 1) * 2 : 0;
 133       break;
 134    case GL_QUADS:
 135       num_primitives = (count / 4) * 2;
 136       break;
 137    case GL_LINES_ADJACENCY:
 138       num_primitives = count / 4;
 139       break;
 140    case GL_LINE_STRIP_ADJACENCY:
 141       num_primitives = count >= 4 ? count - 3 : 0;
 142       break;
 143    case GL_TRIANGLES_ADJACENCY:
 144       num_primitives = count / 6;
 145       break;
 146    case GL_TRIANGLE_STRIP_ADJACENCY:
 147       num_primitives = count >= 6 ? (count - 4) / 2 : 0;
 148       break;
 149    default:
 150       assert(!"Unexpected primitive type in count_tessellated_primitives");
 151       num_primitives = 0;
 152       break;
 153    }
 154    return num_primitives * num_instances;
 155 }
 156
 157
 158
 159 /**
 160  * In some degenarate cases we can improve our ability to merge
 161  * consecutive primitives.  For example:
 162  * glBegin(GL_LINE_STRIP);
 163  * glVertex(1);
 164  * glVertex(1);
 165  * glEnd();
 166  * glBegin(GL_LINE_STRIP);
 167  * glVertex(1);
 168  * glVertex(1);
 169  * glEnd();
 170  * Can be merged as a GL_LINES prim with four vertices.
 171  *
 172  * This function converts 2-vertex line strips/loops into GL_LINES, etc.
 173  */
 174 void
 175 vbo_try_prim_conversion(struct _mesa_prim *p)
 176 {
 177    if (p->mode == GL_LINE_STRIP && p->count == 2) {
 178       /* convert 2-vertex line strip to a separate line */
 179       p->mode = GL_LINES;
 180    }
 181    else if ((p->mode == GL_TRIANGLE_STRIP || p->mode == GL_TRIANGLE_FAN)
 182        && p->count == 3) {
 183       /* convert 3-vertex tri strip or fan to a separate triangle */
 184       p->mode = GL_TRIANGLES;
 185    }
 186
 187    /* Note: we can't convert a 4-vertex quad strip to a separate quad
 188     * because the vertex ordering is different.  We'd have to muck
 189     * around in the vertex data to make it work.
 190     */
 191 }
 192
 193
 194 /**
 195  * Helper function for determining if two subsequent glBegin/glEnd
 196  * primitives can be combined.  This is only possible for GL_POINTS,
 197  * GL_LINES, GL_TRIANGLES and GL_QUADS.
 198  * If we return true, it means that we can concatenate p1 onto p0 (and
 199  * discard p1).
 200  */
 201 bool
 202 vbo_can_merge_prims(const struct _mesa_prim *p0, const struct _mesa_prim *p1)
 203 {
 204    if (!p0->begin ||
 205        !p1->begin ||
 206        !p0->end ||
 207        !p1->end)
 208       return false;
 209
 210    /* The prim mode must match (ex: both GL_TRIANGLES) */
 211    if (p0->mode != p1->mode)
 212       return false;
 213
 214    /* p1's vertices must come right after p0 */
 215    if (p0->start + p0->count != p1->start)
 216       return false;
 217
 218    if (p0->basevertex != p1->basevertex ||
 219        p0->num_instances != p1->num_instances ||
 220        p0->base_instance != p1->base_instance)
 221       return false;
 222
 223    /* can always merge subsequent GL_POINTS primitives */
 224    if (p0->mode == GL_POINTS)
 225       return true;
 226
 227    /* independent lines with no extra vertices */
 228    if (p0->mode == GL_LINES && p0->count % 2 == 0 && p1->count % 2 == 0)
 229       return true;
 230
 231    /* independent tris */
 232    if (p0->mode == GL_TRIANGLES && p0->count % 3 == 0 && p1->count % 3 == 0)
 233       return true;
 234
 235    /* independent quads */
 236    if (p0->mode == GL_QUADS && p0->count % 4 == 0 && p1->count % 4 == 0)
 237       return true;
 238
 239    return false;
 240 }
 241
 242
 243 /**
 244  * If we've determined that p0 and p1 can be merged, this function
 245  * concatenates p1 onto p0.
 246  */
 247 void
 248 vbo_merge_prims(struct _mesa_prim *p0, const struct _mesa_prim *p1)
 249 {
 250    assert(vbo_can_merge_prims(p0, p1));
 251
 252    p0->count += p1->count;
 253    p0->end = p1->end;
 254 }