src/mesa/vbo/vbo_exec.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.3
   4  *
   5  * Copyright (C) 1999-2005  Brian Paul   All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  21  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  22  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  23  * OTHER DEALINGS IN THE SOFTWARE.
  24  *
  25  * Authors:
  26  *    Keith Whitwell <keith@tungstengraphics.com>
  27  */
  28
  29
  30 #include "main/api_arrayelt.h"
  31 #include "main/glheader.h"
  32 #include "main/mtypes.h"
  33 #include "main/vtxfmt.h"
  34 #include "vbo_context.h"
  35
  36
  37
  38 void 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    /* Initialize the arrayelt helper
  45     */
  46    if (!ctx->aelt_context &&
  47        !_ae_create_context( ctx ))
  48       return;
  49
  50    vbo_exec_vtx_init( exec );
  51
  52    ctx->Driver.NeedFlush = 0;
  53    ctx->Driver.CurrentExecPrimitive = PRIM_OUTSIDE_BEGIN_END;
  54    ctx->Driver.BeginVertices = vbo_exec_BeginVertices;
  55    ctx->Driver.FlushVertices = vbo_exec_FlushVertices;
  56
  57    vbo_exec_invalidate_state( ctx, ~0 );
  58 }
  59
  60
  61 void vbo_exec_destroy( struct gl_context *ctx )
  62 {
  63    struct vbo_exec_context *exec = &vbo_context(ctx)->exec;
  64
  65    if (ctx->aelt_context) {
  66       _ae_destroy_context( ctx );
  67       ctx->aelt_context = NULL;
  68    }
  69
  70    vbo_exec_vtx_destroy( exec );
  71 }
  72
  73
  74 /**
  75  * Really want to install these callbacks to a central facility to be
  76  * invoked according to the state flags.  That will have to wait for a
  77  * mesa rework:
  78  */
  79 void vbo_exec_invalidate_state( struct gl_context *ctx, GLuint new_state )
  80 {
  81    struct vbo_context *vbo = vbo_context(ctx);
  82    struct vbo_exec_context *exec = &vbo->exec;
  83
  84    if (!exec->validating && new_state & (_NEW_PROGRAM|_NEW_ARRAY)) {
  85       exec->array.recalculate_inputs = GL_TRUE;
  86
  87       /* If we ended up here because a VAO was deleted, the _DrawArrays
  88        * pointer which pointed to the VAO might be invalid now, so set it
  89        * to NULL.  This prevents crashes in driver functions like Clear
  90        * where driver state validation might occur, but the vbo module is
  91        * still in an invalid state.
  92        *
  93        * Drivers should skip vertex array state validation if _DrawArrays
  94        * is NULL.  It also has no effect on performance, because attrib
  95        * bindings will be recalculated anyway.
  96        */
  97       if (vbo->last_draw_method == DRAW_ARRAYS) {
  98          ctx->Array._DrawArrays = NULL;
  99          vbo->last_draw_method = DRAW_NONE;
 100       }
 101    }
 102
 103    if (new_state & _NEW_EVAL)
 104       exec->eval.recalculate_maps = 1;
 105
 106    _ae_invalidate_state(ctx, new_state);
 107 }
 108
 109
 110 /**
 111  * Figure out the number of transform feedback primitives that will be output
 112  * considering the drawing mode, number of vertices, and instance count,
 113  * assuming that no geometry shading is done and primitive restart is not
 114  * used.
 115  *
 116  * This is used by driver back-ends in implementing the PRIMITIVES_GENERATED
 117  * and TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN queries.  It is also used to
 118  * pre-validate draw calls in GLES3 (where draw calls only succeed if there is
 119  * enough room in the transform feedback buffer for the result).
 120  */
 121 size_t
 122 vbo_count_tessellated_primitives(GLenum mode, GLuint count,
 123                                  GLuint num_instances)
 124 {
 125    size_t num_primitives;
 126    switch (mode) {
 127    case GL_POINTS:
 128       num_primitives = count;
 129       break;
 130    case GL_LINE_STRIP:
 131       num_primitives = count >= 2 ? count - 1 : 0;
 132       break;
 133    case GL_LINE_LOOP:
 134       num_primitives = count >= 2 ? count : 0;
 135       break;
 136    case GL_LINES:
 137       num_primitives = count / 2;
 138       break;
 139    case GL_TRIANGLE_STRIP:
 140    case GL_TRIANGLE_FAN:
 141    case GL_POLYGON:
 142       num_primitives = count >= 3 ? count - 2 : 0;
 143       break;
 144    case GL_TRIANGLES:
 145       num_primitives = count / 3;
 146       break;
 147    case GL_QUAD_STRIP:
 148       num_primitives = count >= 4 ? ((count / 2) - 1) * 2 : 0;
 149       break;
 150    case GL_QUADS:
 151       num_primitives = (count / 4) * 2;
 152       break;
 153    default:
 154       assert(!"Unexpected primitive type in count_tessellated_primitives");
 155       num_primitives = 0;
 156       break;
 157    }
 158    return num_primitives * num_instances;
 159 }
 160
 161
 162
 163 /**
 164  * In some degenarate cases we can improve our ability to merge
 165  * consecutive primitives.  For example:
 166  * glBegin(GL_LINE_STRIP);
 167  * glVertex(1);
 168  * glVertex(1);
 169  * glEnd();
 170  * glBegin(GL_LINE_STRIP);
 171  * glVertex(1);
 172  * glVertex(1);
 173  * glEnd();
 174  * Can be merged as a GL_LINES prim with four vertices.
 175  *
 176  * This function converts 2-vertex line strips/loops into GL_LINES, etc.
 177  */
 178 void
 179 vbo_try_prim_conversion(struct _mesa_prim *p)
 180 {
 181    if (p->mode == GL_LINE_STRIP && p->count == 2) {
 182       /* convert 2-vertex line strip to a separate line */
 183       p->mode = GL_LINES;
 184    }
 185    else if ((p->mode == GL_TRIANGLE_STRIP || p->mode == GL_TRIANGLE_FAN)
 186        && p->count == 3) {
 187       /* convert 3-vertex tri strip or fan to a separate triangle */
 188       p->mode = GL_TRIANGLES;
 189    }
 190
 191    /* Note: we can't convert a 4-vertex quad strip to a separate quad
 192     * because the vertex ordering is different.  We'd have to muck
 193     * around in the vertex data to make it work.
 194     */
 195 }
 196
 197
 198 /**
 199  * Helper function for determining if two subsequent glBegin/glEnd
 200  * primitives can be combined.  This is only possible for GL_POINTS,
 201  * GL_LINES, GL_TRIANGLES and GL_QUADS.
 202  * If we return true, it means that we can concatenate p1 onto p0 (and
 203  * discard p1).
 204  */
 205 bool
 206 vbo_can_merge_prims(const struct _mesa_prim *p0, const struct _mesa_prim *p1)
 207 {
 208    if (!p0->begin ||
 209        !p1->begin ||
 210        !p0->end ||
 211        !p1->end)
 212       return false;
 213
 214    /* The prim mode must match (ex: both GL_TRIANGLES) */
 215    if (p0->mode != p1->mode)
 216       return false;
 217
 218    /* p1's vertices must come right after p0 */
 219    if (p0->start + p0->count != p1->start)
 220       return false;
 221
 222    if (p0->basevertex != p1->basevertex ||
 223        p0->num_instances != p1->num_instances ||
 224        p0->base_instance != p1->base_instance)
 225       return false;
 226
 227    /* can always merge subsequent GL_POINTS primitives */
 228    if (p0->mode == GL_POINTS)
 229       return true;
 230
 231    /* independent lines with no extra vertices */
 232    if (p0->mode == GL_LINES && p0->count % 2 == 0 && p1->count % 2 == 0)
 233       return true;
 234
 235    /* independent tris */
 236    if (p0->mode == GL_TRIANGLES && p0->count % 3 == 0 && p1->count % 3 == 0)
 237       return true;
 238
 239    /* independent quads */
 240    if (p0->mode == GL_QUADS && p0->count % 4 == 0 && p1->count % 4 == 0)
 241       return true;
 242
 243    return false;
 244 }
 245
 246
 247 /**
 248  * If we've determined that p0 and p1 can be merged, this function
 249  * concatenates p1 onto p0.
 250  */
 251 void
 252 vbo_merge_prims(struct _mesa_prim *p0, const struct _mesa_prim *p1)
 253 {
 254    assert(vbo_can_merge_prims(p0, p1));
 255
 256    p0->count += p1->count;
 257    p0->end = p1->end;
 258 }