summaryrefslogtreecommitdiffstats
path: root/src/mesa/main/api_validate.c
blob: ae3e118f426a084044646b4c5b1abf4454ee9353 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
/*
 * Mesa 3-D graphics library
 *
 * Copyright (C) 1999-2007  Brian Paul   All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

#include <stdbool.h>
#include "glheader.h"
#include "api_validate.h"
#include "arrayobj.h"
#include "bufferobj.h"
#include "context.h"
#include "imports.h"
#include "mtypes.h"
#include "enums.h"
#include "vbo/vbo.h"
#include "transformfeedback.h"
#include <stdbool.h>


/**
 * Check if OK to draw arrays/elements.
 */
static bool
check_valid_to_render(struct gl_context *ctx, const char *function)
{
   if (!_mesa_valid_to_render(ctx, function)) {
      return false;
   }

   switch (ctx->API) {
   case API_OPENGLES2:
      /* For ES2, we can draw if we have a vertex program/shader). */
      return ctx->VertexProgram._Current != NULL;

   case API_OPENGLES:
      /* For OpenGL ES, only draw if we have vertex positions
       */
      if (!ctx->Array.VAO->VertexAttrib[VERT_ATTRIB_POS].Enabled)
         return false;
      break;

   case API_OPENGL_CORE:
      /* Section 10.4 (Drawing Commands Using Vertex Arrays) of the OpenGL 4.5
       * Core Profile spec says:
       *
       *     "An INVALID_OPERATION error is generated if no vertex array
       *     object is bound (see section 10.3.1)."
       */
      if (ctx->Array.VAO == ctx->Array.DefaultVAO) {
         _mesa_error(ctx, GL_INVALID_OPERATION, "%s(no VAO bound)", function);
         return false;
      }

      /* The spec argues that this is allowed because a tess ctrl shader
       * without a tess eval shader can be used with transform feedback.
       * However, glBeginTransformFeedback doesn't allow GL_PATCHES and
       * therefore doesn't allow tessellation.
       *
       * Further investigation showed that this is indeed a spec bug and
       * a tess ctrl shader without a tess eval shader shouldn't have been
       * allowed, because there is no API in GL 4.0 that can make use this
       * to produce something useful.
       *
       * Also, all vendors except one don't support a tess ctrl shader without
       * a tess eval shader anyway.
       */
      if (ctx->TessCtrlProgram._Current && !ctx->TessEvalProgram._Current) {
         _mesa_error(ctx, GL_INVALID_OPERATION,
                     "%s(tess eval shader is missing)", function);
         return false;
      }

      /* Section 7.3 (Program Objects) of the OpenGL 4.5 Core Profile spec
       * says:
       *
       *     "If there is no active program for the vertex or fragment shader
       *     stages, the results of vertex and/or fragment processing will be
       *     undefined. However, this is not an error."
       *
       * The fragment shader is not tested here because other state (e.g.,
       * GL_RASTERIZER_DISCARD) affects whether or not we actually care.
       */
      return ctx->VertexProgram._Current != NULL;

   case API_OPENGL_COMPAT:
      if (ctx->VertexProgram._Current != NULL) {
         /* Draw regardless of whether or not we have any vertex arrays.
          * (Ex: could draw a point using a constant vertex pos)
          */
         return true;
      } else {
         /* Draw if we have vertex positions (GL_VERTEX_ARRAY or generic
          * array [0]).
          */
         return (ctx->Array.VAO->VertexAttrib[VERT_ATTRIB_POS].Enabled ||
                 ctx->Array.VAO->VertexAttrib[VERT_ATTRIB_GENERIC0].Enabled);
      }
      break;

   default:
      unreachable("Invalid API value in check_valid_to_render()");
   }

   if (!_mesa_all_buffers_are_unmapped(ctx->Array.VAO)) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "%s(vertex buffers are mapped)", function);
      return false;
   }

   return true;
}


/**
 * Is 'mode' a valid value for glBegin(), glDrawArrays(), glDrawElements(),
 * etc?  The set of legal values depends on whether geometry shaders/programs
 * are supported.
 * Note: This may be called during display list compilation.
 */
bool
_mesa_is_valid_prim_mode(struct gl_context *ctx, GLenum mode)
{
   /* The overwhelmingly common case is (mode <= GL_TRIANGLE_FAN).  Test that
    * first and exit.  You would think that a switch-statement would be the
    * right approach, but at least GCC 4.7.2 generates some pretty dire code
    * for the common case.
    */
   if (likely(mode <= GL_TRIANGLE_FAN))
      return true;

   if (mode <= GL_POLYGON)
      return (ctx->API == API_OPENGL_COMPAT);

   if (mode <= GL_TRIANGLE_STRIP_ADJACENCY)
      return _mesa_has_geometry_shaders(ctx);

   if (mode == GL_PATCHES)
      return _mesa_has_tessellation(ctx);

   return false;
}


/**
 * Is 'mode' a valid value for glBegin(), glDrawArrays(), glDrawElements(),
 * etc?  Also, do additional checking related to transformation feedback.
 * Note: this function cannot be called during glNewList(GL_COMPILE) because
 * this code depends on current transform feedback state.
 * Also, do additional checking related to tessellation shaders.
 */
GLboolean
_mesa_valid_prim_mode(struct gl_context *ctx, GLenum mode, const char *name)
{
   bool valid_enum = _mesa_is_valid_prim_mode(ctx, mode);

   if (!valid_enum) {
      _mesa_error(ctx, GL_INVALID_ENUM, "%s(mode=%x)", name, mode);
      return GL_FALSE;
   }

   /* From the OpenGL 4.5 specification, section 11.3.1:
    *
    * The error INVALID_OPERATION is generated if Begin, or any command that
    * implicitly calls Begin, is called when a geometry shader is active and:
    *
    * * the input primitive type of the current geometry shader is
    *   POINTS and <mode> is not POINTS,
    *
    * * the input primitive type of the current geometry shader is
    *   LINES and <mode> is not LINES, LINE_STRIP, or LINE_LOOP,
    *
    * * the input primitive type of the current geometry shader is
    *   TRIANGLES and <mode> is not TRIANGLES, TRIANGLE_STRIP or
    *   TRIANGLE_FAN,
    *
    * * the input primitive type of the current geometry shader is
    *   LINES_ADJACENCY_ARB and <mode> is not LINES_ADJACENCY_ARB or
    *   LINE_STRIP_ADJACENCY_ARB, or
    *
    * * the input primitive type of the current geometry shader is
    *   TRIANGLES_ADJACENCY_ARB and <mode> is not
    *   TRIANGLES_ADJACENCY_ARB or TRIANGLE_STRIP_ADJACENCY_ARB.
    *
    * The GL spec doesn't mention any interaction with tessellation, which
    * is clearly a spec bug. The same rule should apply, but instead of
    * the draw primitive mode, the tessellation evaluation shader primitive
    * mode should be used for the checking.
   */
   if (ctx->_Shader->CurrentProgram[MESA_SHADER_GEOMETRY]) {
      const GLenum geom_mode =
         ctx->_Shader->CurrentProgram[MESA_SHADER_GEOMETRY]->
            _LinkedShaders[MESA_SHADER_GEOMETRY]->info.Geom.InputType;
      struct gl_shader_program *tes =
         ctx->_Shader->CurrentProgram[MESA_SHADER_TESS_EVAL];
      GLenum mode_before_gs = mode;

      if (tes) {
         struct gl_linked_shader *tes_sh =
            tes->_LinkedShaders[MESA_SHADER_TESS_EVAL];
         if (tes_sh->info.TessEval.PointMode)
            mode_before_gs = GL_POINTS;
         else if (tes_sh->info.TessEval.PrimitiveMode == GL_ISOLINES)
            mode_before_gs = GL_LINES;
         else
            /* the GL_QUADS mode generates triangles too */
            mode_before_gs = GL_TRIANGLES;
      }

      switch (mode_before_gs) {
      case GL_POINTS:
         valid_enum = (geom_mode == GL_POINTS);
         break;
      case GL_LINES:
      case GL_LINE_LOOP:
      case GL_LINE_STRIP:
         valid_enum = (geom_mode == GL_LINES);
         break;
      case GL_TRIANGLES:
      case GL_TRIANGLE_STRIP:
      case GL_TRIANGLE_FAN:
         valid_enum = (geom_mode == GL_TRIANGLES);
         break;
      case GL_QUADS:
      case GL_QUAD_STRIP:
      case GL_POLYGON:
         valid_enum = false;
         break;
      case GL_LINES_ADJACENCY:
      case GL_LINE_STRIP_ADJACENCY:
         valid_enum = (geom_mode == GL_LINES_ADJACENCY);
         break;
      case GL_TRIANGLES_ADJACENCY:
      case GL_TRIANGLE_STRIP_ADJACENCY:
         valid_enum = (geom_mode == GL_TRIANGLES_ADJACENCY);
         break;
      default:
         valid_enum = false;
         break;
      }
      if (!valid_enum) {
         _mesa_error(ctx, GL_INVALID_OPERATION,
                     "%s(mode=%s vs geometry shader input %s)",
                     name,
                     _mesa_lookup_prim_by_nr(mode_before_gs),
                     _mesa_lookup_prim_by_nr(geom_mode));
         return GL_FALSE;
      }
   }

   /* From the OpenGL 4.0 (Core Profile) spec (section 2.12):
    *
    *     "Tessellation operates only on patch primitives. If tessellation is
    *      active, any command that transfers vertices to the GL will
    *      generate an INVALID_OPERATION error if the primitive mode is not
    *      PATCHES.
    *      Patch primitives are not supported by pipeline stages below the
    *      tessellation evaluation shader. If there is no active program
    *      object or the active program object does not contain a tessellation
    *      evaluation shader, the error INVALID_OPERATION is generated by any
    *      command that transfers vertices to the GL if the primitive mode is
    *      PATCHES."
    *
    */
   if (ctx->_Shader->CurrentProgram[MESA_SHADER_TESS_EVAL] ||
       ctx->_Shader->CurrentProgram[MESA_SHADER_TESS_CTRL]) {
      if (mode != GL_PATCHES) {
         _mesa_error(ctx, GL_INVALID_OPERATION,
                     "only GL_PATCHES valid with tessellation");
         return GL_FALSE;
      }
   }
   else {
      if (mode == GL_PATCHES) {
         _mesa_error(ctx, GL_INVALID_OPERATION,
                     "GL_PATCHES only valid with tessellation");
         return GL_FALSE;
      }
   }

   /* From the GL_EXT_transform_feedback spec:
    *
    *     "The error INVALID_OPERATION is generated if Begin, or any command
    *      that performs an explicit Begin, is called when:
    *
    *      * a geometry shader is not active and <mode> does not match the
    *        allowed begin modes for the current transform feedback state as
    *        given by table X.1.
    *
    *      * a geometry shader is active and the output primitive type of the
    *        geometry shader does not match the allowed begin modes for the
    *        current transform feedback state as given by table X.1.
    *
    */
   if (_mesa_is_xfb_active_and_unpaused(ctx)) {
      GLboolean pass = GL_TRUE;

      if(ctx->_Shader->CurrentProgram[MESA_SHADER_GEOMETRY]) {
         switch (ctx->_Shader->CurrentProgram[MESA_SHADER_GEOMETRY]->
                    _LinkedShaders[MESA_SHADER_GEOMETRY]->
                    info.Geom.OutputType) {
         case GL_POINTS:
            pass = ctx->TransformFeedback.Mode == GL_POINTS;
            break;
         case GL_LINE_STRIP:
            pass = ctx->TransformFeedback.Mode == GL_LINES;
            break;
         case GL_TRIANGLE_STRIP:
            pass = ctx->TransformFeedback.Mode == GL_TRIANGLES;
            break;
         default:
            pass = GL_FALSE;
         }
      }
      else if (ctx->_Shader->CurrentProgram[MESA_SHADER_TESS_EVAL]) {
         struct gl_shader_program *tes =
            ctx->_Shader->CurrentProgram[MESA_SHADER_TESS_EVAL];
         struct gl_linked_shader *tes_sh =
            tes->_LinkedShaders[MESA_SHADER_TESS_EVAL];
         if (tes_sh->info.TessEval.PointMode)
            pass = ctx->TransformFeedback.Mode == GL_POINTS;
         else if (tes_sh->info.TessEval.PrimitiveMode == GL_ISOLINES)
            pass = ctx->TransformFeedback.Mode == GL_LINES;
         else
            pass = ctx->TransformFeedback.Mode == GL_TRIANGLES;
      }
      else {
         switch (mode) {
         case GL_POINTS:
            pass = ctx->TransformFeedback.Mode == GL_POINTS;
            break;
         case GL_LINES:
         case GL_LINE_STRIP:
         case GL_LINE_LOOP:
            pass = ctx->TransformFeedback.Mode == GL_LINES;
            break;
         default:
            pass = ctx->TransformFeedback.Mode == GL_TRIANGLES;
            break;
         }
      }
      if (!pass) {
         _mesa_error(ctx, GL_INVALID_OPERATION,
                         "%s(mode=%s vs transform feedback %s)",
                         name,
                         _mesa_lookup_prim_by_nr(mode),
                         _mesa_lookup_prim_by_nr(ctx->TransformFeedback.Mode));
         return GL_FALSE;
      }
   }

   return GL_TRUE;
}

/**
 * Verify that the element type is valid.
 *
 * Generates \c GL_INVALID_ENUM and returns \c false if it is not.
 */
static bool
valid_elements_type(struct gl_context *ctx, GLenum type, const char *name)
{
   switch (type) {
   case GL_UNSIGNED_BYTE:
   case GL_UNSIGNED_SHORT:
   case GL_UNSIGNED_INT:
      return true;

   default:
      _mesa_error(ctx, GL_INVALID_ENUM, "%s(type = %s)", name,
                  _mesa_enum_to_string(type));
      return false;
   }
}

static bool
validate_DrawElements_common(struct gl_context *ctx,
                             GLenum mode, GLsizei count, GLenum type,
                             const GLvoid *indices,
                             const char *caller)
{
   /* From the GLES3 specification, section 2.14.2 (Transform Feedback
    * Primitive Capture):
    *
    *   The error INVALID_OPERATION is also generated by DrawElements,
    *   DrawElementsInstanced, and DrawRangeElements while transform feedback
    *   is active and not paused, regardless of mode.
    */
   if (_mesa_is_gles3(ctx) && !ctx->Extensions.OES_geometry_shader &&
       _mesa_is_xfb_active_and_unpaused(ctx)) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "%s(transform feedback active)", caller);
      return false;
   }

   if (count < 0) {
      _mesa_error(ctx, GL_INVALID_VALUE, "%s(count)", caller);
      return false;
   }

   if (!_mesa_valid_prim_mode(ctx, mode, caller)) {
      return false;
   }

   if (!valid_elements_type(ctx, type, caller))
      return false;

   if (!check_valid_to_render(ctx, caller))
      return false;

   /* Not using a VBO for indices, so avoid NULL pointer derefs later.
    */
   if (!_mesa_is_bufferobj(ctx->Array.VAO->IndexBufferObj) && indices == NULL)
      return false;

   if (count == 0)
      return false;

   return true;
}

/**
 * Error checking for glDrawElements().  Includes parameter checking
 * and VBO bounds checking.
 * \return GL_TRUE if OK to render, GL_FALSE if error found
 */
GLboolean
_mesa_validate_DrawElements(struct gl_context *ctx,
                            GLenum mode, GLsizei count, GLenum type,
                            const GLvoid *indices)
{
   FLUSH_CURRENT(ctx, 0);

   return validate_DrawElements_common(ctx, mode, count, type, indices,
                                       "glDrawElements");
}


/**
 * Error checking for glMultiDrawElements().  Includes parameter checking
 * and VBO bounds checking.
 * \return GL_TRUE if OK to render, GL_FALSE if error found
 */
GLboolean
_mesa_validate_MultiDrawElements(struct gl_context *ctx,
                                 GLenum mode, const GLsizei *count,
                                 GLenum type, const GLvoid * const *indices,
                                 GLuint primcount)
{
   unsigned i;

   FLUSH_CURRENT(ctx, 0);

   for (i = 0; i < primcount; i++) {
      if (count[i] < 0) {
         _mesa_error(ctx, GL_INVALID_VALUE,
                     "glMultiDrawElements(count)" );
         return GL_FALSE;
      }
   }

   if (!_mesa_valid_prim_mode(ctx, mode, "glMultiDrawElements")) {
      return GL_FALSE;
   }

   if (!valid_elements_type(ctx, type, "glMultiDrawElements"))
      return GL_FALSE;

   if (!check_valid_to_render(ctx, "glMultiDrawElements"))
      return GL_FALSE;

   /* Not using a VBO for indices, so avoid NULL pointer derefs later.
    */
   if (!_mesa_is_bufferobj(ctx->Array.VAO->IndexBufferObj)) {
      for (i = 0; i < primcount; i++) {
         if (!indices[i])
            return GL_FALSE;
      }
   }

   return GL_TRUE;
}


/**
 * Error checking for glDrawRangeElements().  Includes parameter checking
 * and VBO bounds checking.
 * \return GL_TRUE if OK to render, GL_FALSE if error found
 */
GLboolean
_mesa_validate_DrawRangeElements(struct gl_context *ctx, GLenum mode,
                                 GLuint start, GLuint end,
                                 GLsizei count, GLenum type,
                                 const GLvoid *indices)
{
   FLUSH_CURRENT(ctx, 0);

   if (end < start) {
      _mesa_error(ctx, GL_INVALID_VALUE, "glDrawRangeElements(end<start)");
      return GL_FALSE;
   }

   return validate_DrawElements_common(ctx, mode, count, type, indices,
                                       "glDrawRangeElements");
}

static bool
validate_draw_arrays(struct gl_context *ctx, const char *func,
                     GLenum mode, GLsizei count, GLsizei numInstances)
{
   struct gl_transform_feedback_object *xfb_obj
      = ctx->TransformFeedback.CurrentObject;
   FLUSH_CURRENT(ctx, 0);

   if (count < 0) {
      _mesa_error(ctx, GL_INVALID_VALUE, "%s(count)", func);
      return false;
   }

   if (!_mesa_valid_prim_mode(ctx, mode, func))
      return false;

   if (!check_valid_to_render(ctx, func))
      return false;

   /* From the GLES3 specification, section 2.14.2 (Transform Feedback
    * Primitive Capture):
    *
    *   The error INVALID_OPERATION is generated by DrawArrays and
    *   DrawArraysInstanced if recording the vertices of a primitive to the
    *   buffer objects being used for transform feedback purposes would result
    *   in either exceeding the limits of any buffer object’s size, or in
    *   exceeding the end position offset + size − 1, as set by
    *   BindBufferRange.
    *
    * This is in contrast to the behaviour of desktop GL, where the extra
    * primitives are silently dropped from the transform feedback buffer.
    *
    * This text is removed in ES 3.2, presumably because it's not really
    * implementable with geometry and tessellation shaders.  In fact,
    * the OES_geometry_shader spec says:
    *
    *    "(13) Does this extension change how transform feedback operates
    *     compared to unextended OpenGL ES 3.0 or 3.1?
    *
    *     RESOLVED: Yes. Because dynamic geometry amplification in a geometry
    *     shader can make it difficult if not impossible to predict the amount
    *     of geometry that may be generated in advance of executing the shader,
    *     the draw-time error for transform feedback buffer overflow conditions
    *     is removed and replaced with the GL behavior (primitives are not
    *     written and the corresponding counter is not updated)..."
    */
   if (_mesa_is_gles3(ctx) && _mesa_is_xfb_active_and_unpaused(ctx) &&
       !_mesa_has_OES_geometry_shader(ctx) &&
       !_mesa_has_OES_tessellation_shader(ctx)) {
      size_t prim_count = vbo_count_tessellated_primitives(mode, count, 1);
      if (xfb_obj->GlesRemainingPrims < prim_count) {
         _mesa_error(ctx, GL_INVALID_OPERATION,
                     "%s(exceeds transform feedback size)", func);
         return false;
      }
      xfb_obj->GlesRemainingPrims -= prim_count;
   }

   if (count == 0)
      return false;

   return true;
}

/**
 * Called from the tnl module to error check the function parameters and
 * verify that we really can draw something.
 * \return GL_TRUE if OK to render, GL_FALSE if error found
 */
GLboolean
_mesa_validate_DrawArrays(struct gl_context *ctx, GLenum mode, GLsizei count)
{
   return validate_draw_arrays(ctx, "glDrawArrays", mode, count, 1);
}


GLboolean
_mesa_validate_DrawArraysInstanced(struct gl_context *ctx, GLenum mode, GLint first,
                                   GLsizei count, GLsizei numInstances)
{
   if (first < 0) {
      _mesa_error(ctx, GL_INVALID_VALUE,
                  "glDrawArraysInstanced(start=%d)", first);
      return GL_FALSE;
   }

   if (numInstances <= 0) {
      if (numInstances < 0)
         _mesa_error(ctx, GL_INVALID_VALUE,
                     "glDrawArraysInstanced(numInstances=%d)", numInstances);
      return GL_FALSE;
   }

   return validate_draw_arrays(ctx, "glDrawArraysInstanced", mode, count, 1);
}


GLboolean
_mesa_validate_DrawElementsInstanced(struct gl_context *ctx,
                                     GLenum mode, GLsizei count, GLenum type,
                                     const GLvoid *indices, GLsizei numInstances)
{
   FLUSH_CURRENT(ctx, 0);

   if (numInstances < 0) {
      _mesa_error(ctx, GL_INVALID_VALUE,
                  "glDrawElementsInstanced(numInstances=%d)", numInstances);
      return GL_FALSE;
   }

   return validate_DrawElements_common(ctx, mode, count, type, indices,
                                       "glDrawElementsInstanced")
      && (numInstances > 0);
}


GLboolean
_mesa_validate_DrawTransformFeedback(struct gl_context *ctx,
                                     GLenum mode,
                                     struct gl_transform_feedback_object *obj,
                                     GLuint stream,
                                     GLsizei numInstances)
{
   FLUSH_CURRENT(ctx, 0);

   if (!_mesa_valid_prim_mode(ctx, mode, "glDrawTransformFeedback*(mode)")) {
      return GL_FALSE;
   }

   if (!obj) {
      _mesa_error(ctx, GL_INVALID_VALUE, "glDrawTransformFeedback*(name)");
      return GL_FALSE;
   }

   /* From the GL 4.5 specification, page 429:
    * "An INVALID_VALUE error is generated if id is not the name of a
    *  transform feedback object."
    */
   if (!obj->EverBound) {
      _mesa_error(ctx, GL_INVALID_VALUE, "glDrawTransformFeedback*(name)");
      return GL_FALSE;
   }

   if (stream >= ctx->Const.MaxVertexStreams) {
      _mesa_error(ctx, GL_INVALID_VALUE,
                  "glDrawTransformFeedbackStream*(index>=MaxVertexStream)");
      return GL_FALSE;
   }

   if (!obj->EndedAnytime) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawTransformFeedback*");
      return GL_FALSE;
   }

   if (numInstances <= 0) {
      if (numInstances < 0)
         _mesa_error(ctx, GL_INVALID_VALUE,
                     "glDrawTransformFeedback*Instanced(numInstances=%d)",
                     numInstances);
      return GL_FALSE;
   }

   if (!check_valid_to_render(ctx, "glDrawTransformFeedback*")) {
      return GL_FALSE;
   }

   return GL_TRUE;
}

static GLboolean
valid_draw_indirect(struct gl_context *ctx,
                    GLenum mode, const GLvoid *indirect,
                    GLsizei size, const char *name)
{
   const uint64_t end = (uint64_t) (uintptr_t) indirect + size;

   /* OpenGL ES 3.1 spec. section 10.5:
    *
    *      "DrawArraysIndirect requires that all data sourced for the
    *      command, including the DrawArraysIndirectCommand
    *      structure,  be in buffer objects,  and may not be called when
    *      the default vertex array object is bound."
    */
   if (ctx->Array.VAO == ctx->Array.DefaultVAO) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "(no VAO bound)");
      return GL_FALSE;
   }

   /* From OpenGL ES 3.1 spec. section 10.5:
    *     "An INVALID_OPERATION error is generated if zero is bound to
    *     VERTEX_ARRAY_BINDING, DRAW_INDIRECT_BUFFER or to any enabled
    *     vertex array."
    *
    * Here we check that for each enabled vertex array we have a vertex
    * buffer bound.
    */
   if (_mesa_is_gles31(ctx) &&
       ctx->Array.VAO->_Enabled != ctx->Array.VAO->VertexAttribBufferMask) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s(No VBO bound)", name);
      return GL_FALSE;
   }

   if (!_mesa_valid_prim_mode(ctx, mode, name))
      return GL_FALSE;

   /* OpenGL ES 3.1 specification, section 10.5:
    *
    *      "An INVALID_OPERATION error is generated if
    *      transform feedback is active and not paused."
    */
   if (_mesa_is_gles31(ctx) && !ctx->Extensions.OES_geometry_shader &&
       _mesa_is_xfb_active_and_unpaused(ctx)) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "%s(TransformFeedback is active and not paused)", name);
   }

   /* From OpenGL version 4.4. section 10.5
    * and OpenGL ES 3.1, section 10.6:
    *
    *      "An INVALID_VALUE error is generated if indirect is not a
    *       multiple of the size, in basic machine units, of uint."
    */
   if ((GLsizeiptr)indirect & (sizeof(GLuint) - 1)) {
      _mesa_error(ctx, GL_INVALID_VALUE,
                  "%s(indirect is not aligned)", name);
      return GL_FALSE;
   }

   if (!_mesa_is_bufferobj(ctx->DrawIndirectBuffer)) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "%s: no buffer bound to DRAW_INDIRECT_BUFFER", name);
      return GL_FALSE;
   }

   if (_mesa_check_disallowed_mapping(ctx->DrawIndirectBuffer)) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "%s(DRAW_INDIRECT_BUFFER is mapped)", name);
      return GL_FALSE;
   }

   /* From the ARB_draw_indirect specification:
    * "An INVALID_OPERATION error is generated if the commands source data
    *  beyond the end of the buffer object [...]"
    */
   if (ctx->DrawIndirectBuffer->Size < end) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "%s(DRAW_INDIRECT_BUFFER too small)", name);
      return GL_FALSE;
   }

   if (!check_valid_to_render(ctx, name))
      return GL_FALSE;

   return GL_TRUE;
}

static inline GLboolean
valid_draw_indirect_elements(struct gl_context *ctx,
                             GLenum mode, GLenum type, const GLvoid *indirect,
                             GLsizeiptr size, const char *name)
{
   if (!valid_elements_type(ctx, type, name))
      return GL_FALSE;

   /*
    * Unlike regular DrawElementsInstancedBaseVertex commands, the indices
    * may not come from a client array and must come from an index buffer.
    * If no element array buffer is bound, an INVALID_OPERATION error is
    * generated.
    */
   if (!_mesa_is_bufferobj(ctx->Array.VAO->IndexBufferObj)) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "%s(no buffer bound to GL_ELEMENT_ARRAY_BUFFER)", name);
      return GL_FALSE;
   }

   return valid_draw_indirect(ctx, mode, indirect, size, name);
}

static inline GLboolean
valid_draw_indirect_multi(struct gl_context *ctx,
                          GLsizei primcount, GLsizei stride,
                          const char *name)
{

   /* From the ARB_multi_draw_indirect specification:
    * "INVALID_VALUE is generated by MultiDrawArraysIndirect or
    *  MultiDrawElementsIndirect if <primcount> is negative."
    *
    * "<primcount> must be positive, otherwise an INVALID_VALUE error will
    *  be generated."
    */
   if (primcount < 0) {
      _mesa_error(ctx, GL_INVALID_VALUE, "%s(primcount < 0)", name);
      return GL_FALSE;
   }


   /* From the ARB_multi_draw_indirect specification:
    * "<stride> must be a multiple of four, otherwise an INVALID_VALUE
    *  error is generated."
    */
   if (stride % 4) {
      _mesa_error(ctx, GL_INVALID_VALUE, "%s(stride %% 4)", name);
      return GL_FALSE;
   }

   return GL_TRUE;
}

GLboolean
_mesa_validate_DrawArraysIndirect(struct gl_context *ctx,
                                  GLenum mode,
                                  const GLvoid *indirect)
{
   const unsigned drawArraysNumParams = 4;

   FLUSH_CURRENT(ctx, 0);

   return valid_draw_indirect(ctx, mode,
                              indirect, drawArraysNumParams * sizeof(GLuint),
                              "glDrawArraysIndirect");
}

GLboolean
_mesa_validate_DrawElementsIndirect(struct gl_context *ctx,
                                    GLenum mode, GLenum type,
                                    const GLvoid *indirect)
{
   const unsigned drawElementsNumParams = 5;

   FLUSH_CURRENT(ctx, 0);

   return valid_draw_indirect_elements(ctx, mode, type,
                                       indirect, drawElementsNumParams * sizeof(GLuint),
                                       "glDrawElementsIndirect");
}

GLboolean
_mesa_validate_MultiDrawArraysIndirect(struct gl_context *ctx,
                                       GLenum mode,
                                       const GLvoid *indirect,
                                       GLsizei primcount, GLsizei stride)
{
   GLsizeiptr size = 0;
   const unsigned drawArraysNumParams = 4;

   FLUSH_CURRENT(ctx, 0);

   /* caller has converted stride==0 to drawArraysNumParams * sizeof(GLuint) */
   assert(stride != 0);

   if (!valid_draw_indirect_multi(ctx, primcount, stride,
                                  "glMultiDrawArraysIndirect"))
      return GL_FALSE;

   /* number of bytes of the indirect buffer which will be read */
   size = primcount
      ? (primcount - 1) * stride + drawArraysNumParams * sizeof(GLuint)
      : 0;

   if (!valid_draw_indirect(ctx, mode, indirect, size,
                            "glMultiDrawArraysIndirect"))
      return GL_FALSE;

   return GL_TRUE;
}

GLboolean
_mesa_validate_MultiDrawElementsIndirect(struct gl_context *ctx,
                                         GLenum mode, GLenum type,
                                         const GLvoid *indirect,
                                         GLsizei primcount, GLsizei stride)
{
   GLsizeiptr size = 0;
   const unsigned drawElementsNumParams = 5;

   FLUSH_CURRENT(ctx, 0);

   /* caller has converted stride==0 to drawElementsNumParams * sizeof(GLuint) */
   assert(stride != 0);

   if (!valid_draw_indirect_multi(ctx, primcount, stride,
                                  "glMultiDrawElementsIndirect"))
      return GL_FALSE;

   /* number of bytes of the indirect buffer which will be read */
   size = primcount
      ? (primcount - 1) * stride + drawElementsNumParams * sizeof(GLuint)
      : 0;

   if (!valid_draw_indirect_elements(ctx, mode, type,
                                     indirect, size,
                                     "glMultiDrawElementsIndirect"))
      return GL_FALSE;

   return GL_TRUE;
}

static GLboolean
valid_draw_indirect_parameters(struct gl_context *ctx,
                               const char *name,
                               GLintptr drawcount)
{
   /* From the ARB_indirect_parameters specification:
    * "INVALID_VALUE is generated by MultiDrawArraysIndirectCountARB or
    *  MultiDrawElementsIndirectCountARB if <drawcount> is not a multiple of
    *  four."
    */
   if (drawcount & 3) {
      _mesa_error(ctx, GL_INVALID_VALUE,
                  "%s(drawcount is not a multiple of 4)", name);
      return GL_FALSE;
   }

   /* From the ARB_indirect_parameters specification:
    * "INVALID_OPERATION is generated by MultiDrawArraysIndirectCountARB or
    *  MultiDrawElementsIndirectCountARB if no buffer is bound to the
    *  PARAMETER_BUFFER_ARB binding point."
    */
   if (!_mesa_is_bufferobj(ctx->ParameterBuffer)) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "%s: no buffer bound to PARAMETER_BUFFER", name);
      return GL_FALSE;
   }

   if (_mesa_check_disallowed_mapping(ctx->ParameterBuffer)) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "%s(PARAMETER_BUFFER is mapped)", name);
      return GL_FALSE;
   }

   /* From the ARB_indirect_parameters specification:
    * "INVALID_OPERATION is generated by MultiDrawArraysIndirectCountARB or
    *  MultiDrawElementsIndirectCountARB if reading a <sizei> typed value
    *  from the buffer bound to the PARAMETER_BUFFER_ARB target at the offset
    *  specified by <drawcount> would result in an out-of-bounds access."
    */
   if (ctx->ParameterBuffer->Size < drawcount + sizeof(GLsizei)) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "%s(PARAMETER_BUFFER too small)", name);
      return GL_FALSE;
   }

   return GL_TRUE;
}

GLboolean
_mesa_validate_MultiDrawArraysIndirectCount(struct gl_context *ctx,
                                            GLenum mode,
                                            GLintptr indirect,
                                            GLintptr drawcount,
                                            GLsizei maxdrawcount,
                                            GLsizei stride)
{
   GLsizeiptr size = 0;
   const unsigned drawArraysNumParams = 4;

   FLUSH_CURRENT(ctx, 0);

   /* caller has converted stride==0 to drawArraysNumParams * sizeof(GLuint) */
   assert(stride != 0);

   if (!valid_draw_indirect_multi(ctx, maxdrawcount, stride,
                                  "glMultiDrawArraysIndirectCountARB"))
      return GL_FALSE;

   /* number of bytes of the indirect buffer which will be read */
   size = maxdrawcount
      ? (maxdrawcount - 1) * stride + drawArraysNumParams * sizeof(GLuint)
      : 0;

   if (!valid_draw_indirect(ctx, mode, (void *)indirect, size,
                            "glMultiDrawArraysIndirectCountARB"))
      return GL_FALSE;

   return valid_draw_indirect_parameters(
         ctx, "glMultiDrawArraysIndirectCountARB", drawcount);
}

GLboolean
_mesa_validate_MultiDrawElementsIndirectCount(struct gl_context *ctx,
                                              GLenum mode, GLenum type,
                                              GLintptr indirect,
                                              GLintptr drawcount,
                                              GLsizei maxdrawcount,
                                              GLsizei stride)
{
   GLsizeiptr size = 0;
   const unsigned drawElementsNumParams = 5;

   FLUSH_CURRENT(ctx, 0);

   /* caller has converted stride==0 to drawElementsNumParams * sizeof(GLuint) */
   assert(stride != 0);

   if (!valid_draw_indirect_multi(ctx, maxdrawcount, stride,
                                  "glMultiDrawElementsIndirectCountARB"))
      return GL_FALSE;

   /* number of bytes of the indirect buffer which will be read */
   size = maxdrawcount
      ? (maxdrawcount - 1) * stride + drawElementsNumParams * sizeof(GLuint)
      : 0;

   if (!valid_draw_indirect_elements(ctx, mode, type,
                                     (void *)indirect, size,
                                     "glMultiDrawElementsIndirectCountARB"))
      return GL_FALSE;

   return valid_draw_indirect_parameters(
         ctx, "glMultiDrawElementsIndirectCountARB", drawcount);
}

static bool
check_valid_to_compute(struct gl_context *ctx, const char *function)
{
   struct gl_shader_program *prog;

   if (!_mesa_has_compute_shaders(ctx)) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "unsupported function (%s) called",
                  function);
      return false;
   }

   /* From the OpenGL 4.3 Core Specification, Chapter 19, Compute Shaders:
    *
    * "An INVALID_OPERATION error is generated if there is no active program
    *  for the compute shader stage."
    */
   prog = ctx->_Shader->CurrentProgram[MESA_SHADER_COMPUTE];
   if (prog == NULL || prog->_LinkedShaders[MESA_SHADER_COMPUTE] == NULL) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "%s(no active compute shader)",
                  function);
      return false;
   }

   return true;
}

GLboolean
_mesa_validate_DispatchCompute(struct gl_context *ctx,
                               const GLuint *num_groups)
{
   int i;
   FLUSH_CURRENT(ctx, 0);

   if (!check_valid_to_compute(ctx, "glDispatchCompute"))
      return GL_FALSE;

   for (i = 0; i < 3; i++) {
      /* From the OpenGL 4.3 Core Specification, Chapter 19, Compute Shaders:
       *
       * "An INVALID_VALUE error is generated if any of num_groups_x,
       *  num_groups_y and num_groups_z are greater than or equal to the
       *  maximum work group count for the corresponding dimension."
       *
       * However, the "or equal to" portions appears to be a specification
       * bug. In all other areas, the specification appears to indicate that
       * the number of workgroups can match the MAX_COMPUTE_WORK_GROUP_COUNT
       * value. For example, under DispatchComputeIndirect:
       *
       * "If any of num_groups_x, num_groups_y or num_groups_z is greater than
       *  the value of MAX_COMPUTE_WORK_GROUP_COUNT for the corresponding
       *  dimension then the results are undefined."
       *
       * Additionally, the OpenGLES 3.1 specification does not contain "or
       * equal to" as an error condition.
       */
      if (num_groups[i] > ctx->Const.MaxComputeWorkGroupCount[i]) {
         _mesa_error(ctx, GL_INVALID_VALUE,
                     "glDispatchCompute(num_groups_%c)", 'x' + i);
         return GL_FALSE;
      }
   }

   return GL_TRUE;
}

static GLboolean
valid_dispatch_indirect(struct gl_context *ctx,
                        GLintptr indirect,
                        GLsizei size, const char *name)
{
   const uint64_t end = (uint64_t) indirect + size;

   if (!check_valid_to_compute(ctx, name))
      return GL_FALSE;

   /* From the OpenGL 4.3 Core Specification, Chapter 19, Compute Shaders:
    *
    * "An INVALID_VALUE error is generated if indirect is negative or is not a
    *  multiple of four."
    */
   if (indirect & (sizeof(GLuint) - 1)) {
      _mesa_error(ctx, GL_INVALID_VALUE,
                  "%s(indirect is not aligned)", name);
      return GL_FALSE;
   }

   if (indirect < 0) {
      _mesa_error(ctx, GL_INVALID_VALUE,
                  "%s(indirect is less than zero)", name);
      return GL_FALSE;
   }

   /* From the OpenGL 4.3 Core Specification, Chapter 19, Compute Shaders:
    *
    * "An INVALID_OPERATION error is generated if no buffer is bound to the
    *  DRAW_INDIRECT_BUFFER binding, or if the command would source data
    *  beyond the end of the buffer object."
    */
   if (!_mesa_is_bufferobj(ctx->DispatchIndirectBuffer)) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "%s: no buffer bound to DISPATCH_INDIRECT_BUFFER", name);
      return GL_FALSE;
   }

   if (_mesa_check_disallowed_mapping(ctx->DispatchIndirectBuffer)) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "%s(DISPATCH_INDIRECT_BUFFER is mapped)", name);
      return GL_FALSE;
   }

   if (ctx->DispatchIndirectBuffer->Size < end) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "%s(DISPATCH_INDIRECT_BUFFER too small)", name);
      return GL_FALSE;
   }

   return GL_TRUE;
}

GLboolean
_mesa_validate_DispatchComputeIndirect(struct gl_context *ctx,
                                       GLintptr indirect)
{
   FLUSH_CURRENT(ctx, 0);

   return valid_dispatch_indirect(ctx, indirect, 3 * sizeof(GLuint),
                                  "glDispatchComputeIndirect");
}