vbo_exec.c revision 848b8605 
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
37void 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   ctx->Driver.BeginVertices = vbo_exec_BeginVertices;
54   ctx->Driver.FlushVertices = vbo_exec_FlushVertices;
55
56   vbo_exec_invalidate_state( ctx, ~0 );
57}
58
59
60void 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 */
78void vbo_exec_invalidate_state( struct gl_context *ctx, GLuint 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 */
105size_t
106vbo_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 */
174void
175vbo_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 */
201bool
202vbo_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 */
247void
248vbo_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}
255