summaryrefslogtreecommitdiff
path: root/src/egl/main/eglconfig.c
blob: 5d38093045c0135fca80f5191663093f0e22cd12 (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
/**************************************************************************
 *
 * Copyright 2008 VMware, Inc.
 * Copyright 2009-2010 Chia-I Wu <olvaffe@gmail.com>
 * Copyright 2010-2011 LunarG, Inc.
 * 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, sub license, 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 (including the
 * next paragraph) 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.
 *
 **************************************************************************/


/**
 * EGL Configuration (pixel format) functions.
 */


#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include "c99_compat.h"
#include "util/macros.h"

#include "eglconfig.h"
#include "egldisplay.h"
#include "eglcurrent.h"
#include "egllog.h"




/**
 * Init the given _EGLconfig to default values.
 * \param id  the configuration's ID.
 *
 * Note that id must be positive for the config to be valid.
 * It is also recommended that when there are N configs, their
 * IDs are from 1 to N respectively.
 */
void
_eglInitConfig(_EGLConfig *conf, _EGLDisplay *dpy, EGLint id)
{
   memset(conf, 0, sizeof(*conf));

   conf->Display = dpy;

   /* some attributes take non-zero default values */
   conf->ConfigID = id;
   conf->ConfigCaveat = EGL_NONE;
   conf->TransparentType = EGL_NONE;
   conf->NativeVisualType = EGL_NONE;
   conf->ColorBufferType = EGL_RGB_BUFFER;
}


/**
 * Link a config to its display and return the handle of the link.
 * The handle can be passed to client directly.
 *
 * Note that we just save the ptr to the config (we don't copy the config).
 */
EGLConfig
_eglLinkConfig(_EGLConfig *conf)
{
   _EGLDisplay *dpy = conf->Display;

   /* sanity check */
   assert(dpy);
   assert(conf->ConfigID > 0);

   if (!dpy->Configs) {
      dpy->Configs = _eglCreateArray("Config", 16);
      if (!dpy->Configs)
         return (EGLConfig) NULL;
   }

   _eglAppendArray(dpy->Configs, (void *) conf);

   return (EGLConfig) conf;
}


/**
 * Lookup a handle to find the linked config.
 * Return NULL if the handle has no corresponding linked config.
 */
_EGLConfig *
_eglLookupConfig(EGLConfig config, _EGLDisplay *dpy)
{
   _EGLConfig *conf;

   if (!dpy)
      return NULL;

   conf = (_EGLConfig *) _eglFindArray(dpy->Configs, (void *) config);
   if (conf)
      assert(conf->Display == dpy);

   return conf;
}


enum type {
   ATTRIB_TYPE_INTEGER,
   ATTRIB_TYPE_BOOLEAN,
   ATTRIB_TYPE_BITMASK,
   ATTRIB_TYPE_ENUM,
   ATTRIB_TYPE_PSEUDO, /* non-queryable */
   ATTRIB_TYPE_PLATFORM, /* platform-dependent */
};

enum criterion {
   ATTRIB_CRITERION_EXACT,
   ATTRIB_CRITERION_ATLEAST,
   ATTRIB_CRITERION_MASK,
   ATTRIB_CRITERION_SPECIAL,
   ATTRIB_CRITERION_IGNORE
};


/* EGL spec Table 3.1 and 3.4 */
static const struct {
   EGLint attr;
   enum type type;
   enum criterion criterion;
   EGLint default_value;
} _eglValidationTable[] =
{
   /* core */
   { EGL_BUFFER_SIZE,               ATTRIB_TYPE_INTEGER,
                                    ATTRIB_CRITERION_ATLEAST,
                                    0 },
   { EGL_RED_SIZE,                  ATTRIB_TYPE_INTEGER,
                                    ATTRIB_CRITERION_ATLEAST,
                                    0 },
   { EGL_GREEN_SIZE,                ATTRIB_TYPE_INTEGER,
                                    ATTRIB_CRITERION_ATLEAST,
                                    0 },
   { EGL_BLUE_SIZE,                 ATTRIB_TYPE_INTEGER,
                                    ATTRIB_CRITERION_ATLEAST,
                                    0 },
   { EGL_LUMINANCE_SIZE,            ATTRIB_TYPE_INTEGER,
                                    ATTRIB_CRITERION_ATLEAST,
                                    0 },
   { EGL_ALPHA_SIZE,                ATTRIB_TYPE_INTEGER,
                                    ATTRIB_CRITERION_ATLEAST,
                                    0 },
   { EGL_ALPHA_MASK_SIZE,           ATTRIB_TYPE_INTEGER,
                                    ATTRIB_CRITERION_ATLEAST,
                                    0 },
   { EGL_BIND_TO_TEXTURE_RGB,       ATTRIB_TYPE_BOOLEAN,
                                    ATTRIB_CRITERION_EXACT,
                                    EGL_DONT_CARE },
   { EGL_BIND_TO_TEXTURE_RGBA,      ATTRIB_TYPE_BOOLEAN,
                                    ATTRIB_CRITERION_EXACT,
                                    EGL_DONT_CARE },
   { EGL_COLOR_BUFFER_TYPE,         ATTRIB_TYPE_ENUM,
                                    ATTRIB_CRITERION_EXACT,
                                    EGL_RGB_BUFFER },
   { EGL_CONFIG_CAVEAT,             ATTRIB_TYPE_ENUM,
                                    ATTRIB_CRITERION_EXACT,
                                    EGL_DONT_CARE },
   { EGL_CONFIG_ID,                 ATTRIB_TYPE_INTEGER,
                                    ATTRIB_CRITERION_EXACT,
                                    EGL_DONT_CARE },
   { EGL_CONFORMANT,                ATTRIB_TYPE_BITMASK,
                                    ATTRIB_CRITERION_MASK,
                                    0 },
   { EGL_DEPTH_SIZE,                ATTRIB_TYPE_INTEGER,
                                    ATTRIB_CRITERION_ATLEAST,
                                    0 },
   { EGL_LEVEL,                     ATTRIB_TYPE_PLATFORM,
                                    ATTRIB_CRITERION_EXACT,
                                    0 },
   { EGL_MAX_PBUFFER_WIDTH,         ATTRIB_TYPE_INTEGER,
                                    ATTRIB_CRITERION_IGNORE,
                                    0 },
   { EGL_MAX_PBUFFER_HEIGHT,        ATTRIB_TYPE_INTEGER,
                                    ATTRIB_CRITERION_IGNORE,
                                    0 },
   { EGL_MAX_PBUFFER_PIXELS,        ATTRIB_TYPE_INTEGER,
                                    ATTRIB_CRITERION_IGNORE,
                                    0 },
   { EGL_MAX_SWAP_INTERVAL,         ATTRIB_TYPE_INTEGER,
                                    ATTRIB_CRITERION_EXACT,
                                    EGL_DONT_CARE },
   { EGL_MIN_SWAP_INTERVAL,         ATTRIB_TYPE_INTEGER,
                                    ATTRIB_CRITERION_EXACT,
                                    EGL_DONT_CARE },
   { EGL_NATIVE_RENDERABLE,         ATTRIB_TYPE_BOOLEAN,
                                    ATTRIB_CRITERION_EXACT,
                                    EGL_DONT_CARE },
   { EGL_NATIVE_VISUAL_ID,          ATTRIB_TYPE_PLATFORM,
                                    ATTRIB_CRITERION_IGNORE,
                                    0 },
   { EGL_NATIVE_VISUAL_TYPE,        ATTRIB_TYPE_PLATFORM,
                                    ATTRIB_CRITERION_EXACT,
                                    EGL_DONT_CARE },
   { EGL_RENDERABLE_TYPE,           ATTRIB_TYPE_BITMASK,
                                    ATTRIB_CRITERION_MASK,
                                    EGL_OPENGL_ES_BIT },
   { EGL_SAMPLE_BUFFERS,            ATTRIB_TYPE_INTEGER,
                                    ATTRIB_CRITERION_ATLEAST,
                                    0 },
   { EGL_SAMPLES,                   ATTRIB_TYPE_INTEGER,
                                    ATTRIB_CRITERION_ATLEAST,
                                    0 },
   { EGL_STENCIL_SIZE,              ATTRIB_TYPE_INTEGER,
                                    ATTRIB_CRITERION_ATLEAST,
                                    0 },
   { EGL_SURFACE_TYPE,              ATTRIB_TYPE_BITMASK,
                                    ATTRIB_CRITERION_MASK,
                                    EGL_WINDOW_BIT },
   { EGL_TRANSPARENT_TYPE,          ATTRIB_TYPE_ENUM,
                                    ATTRIB_CRITERION_EXACT,
                                    EGL_NONE },
   { EGL_TRANSPARENT_RED_VALUE,     ATTRIB_TYPE_INTEGER,
                                    ATTRIB_CRITERION_EXACT,
                                    EGL_DONT_CARE },
   { EGL_TRANSPARENT_GREEN_VALUE,   ATTRIB_TYPE_INTEGER,
                                    ATTRIB_CRITERION_EXACT,
                                    EGL_DONT_CARE },
   { EGL_TRANSPARENT_BLUE_VALUE,    ATTRIB_TYPE_INTEGER,
                                    ATTRIB_CRITERION_EXACT,
                                    EGL_DONT_CARE },
   { EGL_MATCH_NATIVE_PIXMAP,       ATTRIB_TYPE_PSEUDO,
                                    ATTRIB_CRITERION_SPECIAL,
                                    EGL_NONE },
   /* extensions */
   { EGL_Y_INVERTED_NOK,            ATTRIB_TYPE_BOOLEAN,
                                    ATTRIB_CRITERION_EXACT,
                                    EGL_DONT_CARE },
   { EGL_FRAMEBUFFER_TARGET_ANDROID, ATTRIB_TYPE_BOOLEAN,
                                    ATTRIB_CRITERION_EXACT,
                                    EGL_DONT_CARE },
   { EGL_RECORDABLE_ANDROID,        ATTRIB_TYPE_BOOLEAN,
                                    ATTRIB_CRITERION_EXACT,
                                    EGL_DONT_CARE },
};


/**
 * Return true if a config is valid.  When for_matching is true,
 * EGL_DONT_CARE is accepted as a valid attribute value, and checks
 * for conflicting attribute values are skipped.
 *
 * Note that some attributes are platform-dependent and are not
 * checked.
 */
EGLBoolean
_eglValidateConfig(const _EGLConfig *conf, EGLBoolean for_matching)
{
   _EGLDisplay *disp = conf->Display;
   EGLint i, attr, val;
   EGLBoolean valid = EGL_TRUE;

   /* check attributes by their types */
   for (i = 0; i < ARRAY_SIZE(_eglValidationTable); i++) {
      EGLint mask;

      attr = _eglValidationTable[i].attr;
      val = _eglGetConfigKey(conf, attr);

      switch (_eglValidationTable[i].type) {
      case ATTRIB_TYPE_INTEGER:
         switch (attr) {
         case EGL_CONFIG_ID:
            /* config id must be positive */
            if (val <= 0)
               valid = EGL_FALSE;
            break;
         case EGL_SAMPLE_BUFFERS:
            /* there can be at most 1 sample buffer */
            if (val > 1 || val < 0)
               valid = EGL_FALSE;
            break;
         default:
            if (val < 0)
               valid = EGL_FALSE;
            break;
         }
         break;
      case ATTRIB_TYPE_BOOLEAN:
         if (val != EGL_TRUE && val != EGL_FALSE)
            valid = EGL_FALSE;
         break;
      case ATTRIB_TYPE_ENUM:
         switch (attr) {
         case EGL_CONFIG_CAVEAT:
            if (val != EGL_NONE && val != EGL_SLOW_CONFIG &&
                val != EGL_NON_CONFORMANT_CONFIG)
               valid = EGL_FALSE;
            break;
         case EGL_TRANSPARENT_TYPE:
            if (val != EGL_NONE && val != EGL_TRANSPARENT_RGB)
               valid = EGL_FALSE;
            break;
         case EGL_COLOR_BUFFER_TYPE:
            if (val != EGL_RGB_BUFFER && val != EGL_LUMINANCE_BUFFER)
               valid = EGL_FALSE;
            break;
         default:
            assert(0);
            break;
         }
         break;
      case ATTRIB_TYPE_BITMASK:
         switch (attr) {
         case EGL_SURFACE_TYPE:
            mask = EGL_PBUFFER_BIT |
                   EGL_PIXMAP_BIT |
                   EGL_WINDOW_BIT |
                   EGL_VG_COLORSPACE_LINEAR_BIT |
                   EGL_VG_ALPHA_FORMAT_PRE_BIT |
                   EGL_MULTISAMPLE_RESOLVE_BOX_BIT |
                   EGL_SWAP_BEHAVIOR_PRESERVED_BIT;
            if (disp->Extensions.KHR_mutable_render_buffer)
               mask |= EGL_MUTABLE_RENDER_BUFFER_BIT_KHR;
            break;
         case EGL_RENDERABLE_TYPE:
         case EGL_CONFORMANT:
            mask = EGL_OPENGL_ES_BIT |
                   EGL_OPENVG_BIT |
                   EGL_OPENGL_ES2_BIT |
                   EGL_OPENGL_ES3_BIT_KHR |
                   EGL_OPENGL_BIT;
            break;
         default:
            assert(0);
            mask = 0;
            break;
         }
         if (val & ~mask)
            valid = EGL_FALSE;
         break;
      case ATTRIB_TYPE_PLATFORM:
         /* unable to check platform-dependent attributes here */
         break;
      case ATTRIB_TYPE_PSEUDO:
         /* pseudo attributes should not be set */
         if (val != 0)
            valid = EGL_FALSE;
         break;
      }

      if (!valid && for_matching) {
         /* accept EGL_DONT_CARE as a valid value */
         if (val == EGL_DONT_CARE)
            valid = EGL_TRUE;
         if (_eglValidationTable[i].criterion == ATTRIB_CRITERION_SPECIAL)
            valid = EGL_TRUE;
      }
      if (!valid) {
         _eglLog(_EGL_DEBUG,
               "attribute 0x%04x has an invalid value 0x%x", attr, val);
         break;
      }
   }

   /* any invalid attribute value should have been catched */
   if (!valid || for_matching)
      return valid;

   /* now check for conflicting attribute values */

   switch (conf->ColorBufferType) {
   case EGL_RGB_BUFFER:
      if (conf->LuminanceSize)
         valid = EGL_FALSE;
      if (conf->RedSize + conf->GreenSize +
            conf->BlueSize + conf->AlphaSize != conf->BufferSize)
         valid = EGL_FALSE;
      break;
   case EGL_LUMINANCE_BUFFER:
      if (conf->RedSize || conf->GreenSize || conf->BlueSize)
         valid = EGL_FALSE;
      if (conf->LuminanceSize + conf->AlphaSize != conf->BufferSize)
         valid = EGL_FALSE;
      break;
   }
   if (!valid) {
      _eglLog(_EGL_DEBUG, "conflicting color buffer type and channel sizes");
      return EGL_FALSE;
   }

   if (!conf->SampleBuffers && conf->Samples)
      valid = EGL_FALSE;
   if (!valid) {
      _eglLog(_EGL_DEBUG, "conflicting samples and sample buffers");
      return EGL_FALSE;
   }

   if (!(conf->SurfaceType & EGL_WINDOW_BIT)) {
      if (conf->NativeVisualID != 0 || conf->NativeVisualType != EGL_NONE)
         valid = EGL_FALSE;
   }
   if (!(conf->SurfaceType & EGL_PBUFFER_BIT)) {
      if (conf->BindToTextureRGB || conf->BindToTextureRGBA)
         valid = EGL_FALSE;
   }
   if (!valid) {
      _eglLog(_EGL_DEBUG, "conflicting surface type and native visual/texture binding");
      return EGL_FALSE;
   }

   return valid;
}


/**
 * Return true if a config matches the criteria.  This and
 * _eglParseConfigAttribList together implement the algorithm
 * described in "Selection of EGLConfigs".
 *
 * Note that attributes that are special (currently, only
 * EGL_MATCH_NATIVE_PIXMAP) are ignored.
 */
EGLBoolean
_eglMatchConfig(const _EGLConfig *conf, const _EGLConfig *criteria)
{
   EGLint attr, val, i;
   EGLBoolean matched = EGL_TRUE;

   for (i = 0; i < ARRAY_SIZE(_eglValidationTable); i++) {
      EGLint cmp;
      if (_eglValidationTable[i].criterion == ATTRIB_CRITERION_IGNORE)
         continue;

      attr = _eglValidationTable[i].attr;
      cmp = _eglGetConfigKey(criteria, attr);
      if (cmp == EGL_DONT_CARE)
         continue;

      val = _eglGetConfigKey(conf, attr);
      switch (_eglValidationTable[i].criterion) {
      case ATTRIB_CRITERION_EXACT:
         if (val != cmp)
            matched = EGL_FALSE;
         break;
      case ATTRIB_CRITERION_ATLEAST:
         if (val < cmp)
            matched = EGL_FALSE;
         break;
      case ATTRIB_CRITERION_MASK:
         if ((val & cmp) != cmp)
            matched = EGL_FALSE;
         break;
      case ATTRIB_CRITERION_SPECIAL:
         /* ignored here */
         break;
      case ATTRIB_CRITERION_IGNORE:
         unreachable("already handled above");
         break;
      }

      if (!matched) {
#ifndef DEBUG
         /* only print the common errors when DEBUG is not defined */
         if (attr != EGL_RENDERABLE_TYPE)
            break;
#endif
         _eglLog(_EGL_DEBUG,
               "the value (0x%x) of attribute 0x%04x did not meet the criteria (0x%x)",
               val, attr, cmp);
         break;
      }
   }

   return matched;
}

static inline EGLBoolean
_eglIsConfigAttribValid(_EGLConfig *conf, EGLint attr)
{
   if (_eglOffsetOfConfig(attr) < 0)
      return EGL_FALSE;

   switch (attr) {
   case EGL_Y_INVERTED_NOK:
      return conf->Display->Extensions.NOK_texture_from_pixmap;
   case EGL_FRAMEBUFFER_TARGET_ANDROID:
      return conf->Display->Extensions.ANDROID_framebuffer_target;
   case EGL_RECORDABLE_ANDROID:
      return conf->Display->Extensions.ANDROID_recordable;
   default:
      break;
   }

   return EGL_TRUE;
}

/**
 * Initialize a criteria config from the given attribute list.
 * Return EGL_FALSE if any of the attribute is invalid.
 */
EGLBoolean
_eglParseConfigAttribList(_EGLConfig *conf, _EGLDisplay *dpy,
                          const EGLint *attrib_list)
{
   EGLint attr, val, i;

   _eglInitConfig(conf, dpy, EGL_DONT_CARE);

   /* reset to default values */
   for (i = 0; i < ARRAY_SIZE(_eglValidationTable); i++) {
      attr = _eglValidationTable[i].attr;
      val = _eglValidationTable[i].default_value;
      _eglSetConfigKey(conf, attr, val);
   }

   /* parse the list */
   for (i = 0; attrib_list && attrib_list[i] != EGL_NONE; i += 2) {
      attr = attrib_list[i];
      val = attrib_list[i + 1];

      if (!_eglIsConfigAttribValid(conf, attr))
	 return EGL_FALSE;

      _eglSetConfigKey(conf, attr, val);
   }

   if (!_eglValidateConfig(conf, EGL_TRUE))
      return EGL_FALSE;

   /* EGL_LEVEL and EGL_MATCH_NATIVE_PIXMAP cannot be EGL_DONT_CARE */
   if (conf->Level == EGL_DONT_CARE ||
       conf->MatchNativePixmap == EGL_DONT_CARE)
      return EGL_FALSE;

   /* ignore other attributes when EGL_CONFIG_ID is given */
   if (conf->ConfigID != EGL_DONT_CARE) {
      for (i = 0; i < ARRAY_SIZE(_eglValidationTable); i++) {
         attr = _eglValidationTable[i].attr;
         if (attr != EGL_CONFIG_ID)
            _eglSetConfigKey(conf, attr, EGL_DONT_CARE);
      }
   }
   else {
      if (!(conf->SurfaceType & EGL_WINDOW_BIT))
         conf->NativeVisualType = EGL_DONT_CARE;

      if (conf->TransparentType == EGL_NONE) {
         conf->TransparentRedValue = EGL_DONT_CARE;
         conf->TransparentGreenValue = EGL_DONT_CARE;
         conf->TransparentBlueValue = EGL_DONT_CARE;
      }
   }

   return EGL_TRUE;
}


/**
 * Decide the ordering of conf1 and conf2, under the given criteria.
 * When compare_id is true, this implements the algorithm described
 * in "Sorting of EGLConfigs".  When compare_id is false,
 * EGL_CONFIG_ID is not compared.
 *
 * It returns a negative integer if conf1 is considered to come
 * before conf2;  a positive integer if conf2 is considered to come
 * before conf1;  zero if the ordering cannot be decided.
 *
 * Note that EGL_NATIVE_VISUAL_TYPE is platform-dependent and is
 * ignored here.
 */
EGLint
_eglCompareConfigs(const _EGLConfig *conf1, const _EGLConfig *conf2,
                   const _EGLConfig *criteria, EGLBoolean compare_id)
{
   const EGLint compare_attribs[] = {
      EGL_BUFFER_SIZE,
      EGL_SAMPLE_BUFFERS,
      EGL_SAMPLES,
      EGL_DEPTH_SIZE,
      EGL_STENCIL_SIZE,
      EGL_ALPHA_MASK_SIZE,
   };
   EGLint val1, val2;
   EGLint i;

   if (conf1 == conf2)
      return 0;

   /* the enum values have the desired ordering */
   STATIC_ASSERT(EGL_NONE < EGL_SLOW_CONFIG);
   STATIC_ASSERT(EGL_SLOW_CONFIG < EGL_NON_CONFORMANT_CONFIG);
   val1 = conf1->ConfigCaveat - conf2->ConfigCaveat;
   if (val1)
      return val1;

   /* the enum values have the desired ordering */
   STATIC_ASSERT(EGL_RGB_BUFFER < EGL_LUMINANCE_BUFFER);
   val1 = conf1->ColorBufferType - conf2->ColorBufferType;
   if (val1)
      return val1;

   if (criteria) {
      val1 = val2 = 0;
      if (conf1->ColorBufferType == EGL_RGB_BUFFER) {
         if (criteria->RedSize > 0) {
            val1 += conf1->RedSize;
            val2 += conf2->RedSize;
         }
         if (criteria->GreenSize > 0) {
            val1 += conf1->GreenSize;
            val2 += conf2->GreenSize;
         }
         if (criteria->BlueSize > 0) {
            val1 += conf1->BlueSize;
            val2 += conf2->BlueSize;
         }
      }
      else {
         if (criteria->LuminanceSize > 0) {
            val1 += conf1->LuminanceSize;
            val2 += conf2->LuminanceSize;
         }
      }
      if (criteria->AlphaSize > 0) {
         val1 += conf1->AlphaSize;
         val2 += conf2->AlphaSize;
      }
   }
   else {
      /* assume the default criteria, which gives no specific ordering */
      val1 = val2 = 0;
   }

   /* for color bits, larger one is preferred */
   if (val1 != val2)
      return (val2 - val1);

   for (i = 0; i < ARRAY_SIZE(compare_attribs); i++) {
      val1 = _eglGetConfigKey(conf1, compare_attribs[i]);
      val2 = _eglGetConfigKey(conf2, compare_attribs[i]);
      if (val1 != val2)
         return (val1 - val2);
   }

   /* EGL_NATIVE_VISUAL_TYPE cannot be compared here */

   return (compare_id) ? (conf1->ConfigID - conf2->ConfigID) : 0;
}


static inline
void _eglSwapConfigs(const _EGLConfig **conf1, const _EGLConfig **conf2)
{
   const _EGLConfig *tmp = *conf1;
   *conf1 = *conf2;
   *conf2 = tmp;
}


/**
 * Quick sort an array of configs.  This differs from the standard
 * qsort() in that the compare function accepts an additional
 * argument.
 */
static void
_eglSortConfigs(const _EGLConfig **configs, EGLint count,
                EGLint (*compare)(const _EGLConfig *, const _EGLConfig *,
                                  void *),
                void *priv_data)
{
   const EGLint pivot = 0;
   EGLint i, j;

   if (count <= 1)
      return;

   _eglSwapConfigs(&configs[pivot], &configs[count / 2]);
   i = 1;
   j = count - 1;
   do {
      while (i < count && compare(configs[i], configs[pivot], priv_data) < 0)
         i++;
      while (compare(configs[j], configs[pivot], priv_data) > 0)
         j--;
      if (i < j) {
         _eglSwapConfigs(&configs[i], &configs[j]);
         i++;
         j--;
      }
      else if (i == j) {
         i++;
         j--;
         break;
      }
   } while (i <= j);
   _eglSwapConfigs(&configs[pivot], &configs[j]);

   _eglSortConfigs(configs, j, compare, priv_data);
   _eglSortConfigs(configs + i, count - i, compare, priv_data);
}


/**
 * A helper function for implementing eglChooseConfig.  See _eglFilterArray and
 * _eglSortConfigs for the meanings of match and compare.
 */
EGLBoolean
_eglFilterConfigArray(_EGLArray *array, EGLConfig *configs,
                      EGLint config_size, EGLint *num_configs,
                      EGLBoolean (*match)(const _EGLConfig *, void *),
                      EGLint (*compare)(const _EGLConfig *, const _EGLConfig *,
                                        void *),
                      void *priv_data)
{
   _EGLConfig **configList;
   EGLint i, count;

   if (!num_configs)
      return _eglError(EGL_BAD_PARAMETER, "eglChooseConfig");

   /* get the number of matched configs */
   count = _eglFilterArray(array, NULL, 0,
         (_EGLArrayForEach) match, priv_data);
   if (!count) {
      *num_configs = count;
      return EGL_TRUE;
   }

   configList = malloc(sizeof(*configList) * count);
   if (!configList)
      return _eglError(EGL_BAD_ALLOC, "eglChooseConfig(out of memory)");

   /* get the matched configs */
   _eglFilterArray(array, (void **) configList, count,
         (_EGLArrayForEach) match, priv_data);

   /* perform sorting of configs */
   if (configs && count) {
      _eglSortConfigs((const _EGLConfig **) configList, count,
                      compare, priv_data);
      count = MIN2(count, config_size);
      for (i = 0; i < count; i++)
         configs[i] = _eglGetConfigHandle(configList[i]);
   }

   free(configList);

   *num_configs = count;

   return EGL_TRUE;
}


static EGLBoolean
_eglFallbackMatch(const _EGLConfig *conf, void *priv_data)
{
   return _eglMatchConfig(conf, (const _EGLConfig *) priv_data);
}


static EGLint
_eglFallbackCompare(const _EGLConfig *conf1, const _EGLConfig *conf2,
                    void *priv_data)
{
   return _eglCompareConfigs(conf1, conf2,
         (const _EGLConfig *) priv_data, EGL_TRUE);
}


/**
 * Typical fallback routine for eglChooseConfig
 */
EGLBoolean
_eglChooseConfig(_EGLDriver *drv, _EGLDisplay *disp, const EGLint *attrib_list,
                 EGLConfig *configs, EGLint config_size, EGLint *num_configs)
{
   _EGLConfig criteria;

   if (!_eglParseConfigAttribList(&criteria, disp, attrib_list))
      return _eglError(EGL_BAD_ATTRIBUTE, "eglChooseConfig");

   return _eglFilterConfigArray(disp->Configs,
         configs, config_size, num_configs,
         _eglFallbackMatch, _eglFallbackCompare,
         (void *) &criteria);
}


/**
 * Fallback for eglGetConfigAttrib.
 */
EGLBoolean
_eglGetConfigAttrib(_EGLDriver *drv, _EGLDisplay *dpy, _EGLConfig *conf,
                    EGLint attribute, EGLint *value)
{
   if (!_eglIsConfigAttribValid(conf, attribute))
      return _eglError(EGL_BAD_ATTRIBUTE, "eglGetConfigAttrib");

   /* nonqueryable attributes */
   switch (attribute) {
   case EGL_MATCH_NATIVE_PIXMAP:
      return _eglError(EGL_BAD_ATTRIBUTE, "eglGetConfigAttrib");
      break;
   default:
      break;
   }

   if (!value)
      return _eglError(EGL_BAD_PARAMETER, "eglGetConfigAttrib");

   *value = _eglGetConfigKey(conf, attribute);
   return EGL_TRUE;
}


static EGLBoolean
_eglFlattenConfig(void *elem, void *buffer)
{
   _EGLConfig *conf = (_EGLConfig *) elem;
   EGLConfig *handle = (EGLConfig *) buffer;
   *handle = _eglGetConfigHandle(conf);
   return EGL_TRUE;
}

/**
 * Fallback for eglGetConfigs.
 */
EGLBoolean
_eglGetConfigs(_EGLDriver *drv, _EGLDisplay *disp, EGLConfig *configs,
               EGLint config_size, EGLint *num_config)
{
   if (!num_config)
      return _eglError(EGL_BAD_PARAMETER, "eglGetConfigs");

   *num_config = _eglFlattenArray(disp->Configs, (void *) configs,
         sizeof(configs[0]), config_size, _eglFlattenConfig);

   return EGL_TRUE;
}