summaryrefslogtreecommitdiff
path: root/src/egl/main/eglconfig.c
blob: eba608b0ba8e2764c9f03db6c8bd6e0c25efb5e0 (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
/**
 * EGL Configuration (pixel format) functions.
 */


#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include "eglconfig.h"
#include "egldisplay.h"
#include "egldriver.h"
#include "eglglobals.h"
#include "egllog.h"


#define MIN2(A, B)  (((A) < (B)) ? (A) : (B))


/**
 * Convert an _EGLConfig to a __GLcontextModes object.
 * NOTE: This routine may be incomplete - we're only making sure that
 * the fields needed by Mesa (for _mesa_create_context/framebuffer) are
 * set correctly.
 */
void
_eglConfigToContextModesRec(const _EGLConfig *config, __GLcontextModes *mode)
{
   memset(mode, 0, sizeof(*mode));

   mode->rgbMode = GL_TRUE; /* no color index */
   mode->colorIndexMode = GL_FALSE;
   mode->doubleBufferMode = GL_TRUE;  /* always DB for now */
   mode->stereoMode = GL_FALSE;

   mode->redBits = GET_CONFIG_ATTRIB(config, EGL_RED_SIZE);
   mode->greenBits = GET_CONFIG_ATTRIB(config, EGL_GREEN_SIZE);
   mode->blueBits = GET_CONFIG_ATTRIB(config, EGL_BLUE_SIZE);
   mode->alphaBits = GET_CONFIG_ATTRIB(config, EGL_ALPHA_SIZE);
   mode->rgbBits = GET_CONFIG_ATTRIB(config, EGL_BUFFER_SIZE);

   /* no rgba masks - fix? */

   mode->depthBits = GET_CONFIG_ATTRIB(config, EGL_DEPTH_SIZE);
   mode->haveDepthBuffer = mode->depthBits > 0;

   mode->stencilBits = GET_CONFIG_ATTRIB(config, EGL_STENCIL_SIZE);
   mode->haveStencilBuffer = mode->stencilBits > 0;

   /* no accum */

   mode->level = GET_CONFIG_ATTRIB(config, EGL_LEVEL);
   mode->samples = GET_CONFIG_ATTRIB(config, EGL_SAMPLES);
   mode->sampleBuffers = GET_CONFIG_ATTRIB(config, EGL_SAMPLE_BUFFERS);

   /* surface type - not really needed */
   mode->visualType = GLX_TRUE_COLOR;
   mode->renderType = GLX_RGBA_BIT;
}


void
_eglSetConfigAttrib(_EGLConfig *config, EGLint attr, EGLint val)
{
   assert(attr >= FIRST_ATTRIB);
   assert(attr < FIRST_ATTRIB + MAX_ATTRIBS);
   config->Attrib[attr - FIRST_ATTRIB] = val;
}


/**
 * Init the given _EGLconfig to default values.
 * \param id  the configuration's ID.
 */
void
_eglInitConfig(_EGLConfig *config, EGLint id)
{
   memset(config, 0, sizeof(*config));
   config->Handle = id;
   _eglSetConfigAttrib(config, EGL_CONFIG_ID,               id);
   _eglSetConfigAttrib(config, EGL_BIND_TO_TEXTURE_RGB,     EGL_DONT_CARE);
   _eglSetConfigAttrib(config, EGL_BIND_TO_TEXTURE_RGBA,    EGL_DONT_CARE);
   _eglSetConfigAttrib(config, EGL_CONFIG_CAVEAT,           EGL_DONT_CARE);
   _eglSetConfigAttrib(config, EGL_NATIVE_RENDERABLE,       EGL_DONT_CARE);
   _eglSetConfigAttrib(config, EGL_NATIVE_VISUAL_TYPE,      EGL_DONT_CARE);
   _eglSetConfigAttrib(config, EGL_MIN_SWAP_INTERVAL,       EGL_DONT_CARE);
   _eglSetConfigAttrib(config, EGL_MAX_SWAP_INTERVAL,       EGL_DONT_CARE);
   _eglSetConfigAttrib(config, EGL_SURFACE_TYPE,            
                   EGL_SCREEN_BIT_MESA | EGL_PBUFFER_BIT |
                   EGL_PIXMAP_BIT | EGL_WINDOW_BIT);
   _eglSetConfigAttrib(config, EGL_TRANSPARENT_TYPE,        EGL_NONE);
   _eglSetConfigAttrib(config, EGL_TRANSPARENT_RED_VALUE,   EGL_DONT_CARE);
   _eglSetConfigAttrib(config, EGL_TRANSPARENT_GREEN_VALUE, EGL_DONT_CARE);
   _eglSetConfigAttrib(config, EGL_TRANSPARENT_BLUE_VALUE,  EGL_DONT_CARE);
}


/**
 * Given an EGLConfig handle, return the corresponding _EGLConfig object.
 */
_EGLConfig *
_eglLookupConfig(_EGLDriver *drv, EGLDisplay dpy, EGLConfig config)
{
   EGLint i;
   _EGLDisplay *disp = _eglLookupDisplay(dpy);
   for (i = 0; i < disp->NumConfigs; i++) {
      if (disp->Configs[i].Handle == config) {
          return disp->Configs + i;
      }
   }
   return NULL;
}


/**
 * Add the given _EGLConifg to the given display.
 */
_EGLConfig *
_eglAddConfig(_EGLDisplay *display, const _EGLConfig *config)
{
   _EGLConfig *newConfigs;
   EGLint n;

   n = display->NumConfigs;

   newConfigs = (_EGLConfig *) realloc(display->Configs,
                                       (n + 1) * sizeof(_EGLConfig));
   if (newConfigs) {
      display->Configs = newConfigs;
      display->Configs[n] = *config; /* copy struct */
      display->Configs[n].Handle = n;
      display->NumConfigs++;
      return display->Configs + n;
   }
   else {
      return NULL;
   }
}


/**
 * Parse the attrib_list to fill in the fields of the given _egl_config
 * Return EGL_FALSE if any errors, EGL_TRUE otherwise.
 */
EGLBoolean
_eglParseConfigAttribs(_EGLConfig *config, const EGLint *attrib_list)
{
   EGLint i;

   /* set all config attribs to EGL_DONT_CARE */
   for (i = 0; i < MAX_ATTRIBS; i++) {
      config->Attrib[i] = EGL_DONT_CARE;
   }

   for (i = 0; attrib_list && attrib_list[i] != EGL_NONE; i++) {
      if (attrib_list[i] >= EGL_BUFFER_SIZE &&
          attrib_list[i] <= EGL_MAX_SWAP_INTERVAL) {
         EGLint k = attrib_list[i] - FIRST_ATTRIB;
         assert(k >= 0);
         assert(k < MAX_ATTRIBS);
         config->Attrib[k] = attrib_list[++i];
      }
      else {
         _eglError(EGL_BAD_ATTRIBUTE, "eglChooseConfig");
         return EGL_FALSE;
      }
   }
   return EGL_TRUE;
}


#define EXACT 1
#define ATLEAST 2
#define MASK 3
#define SMALLER 4
#define SPECIAL 5
#define NONE 6

struct sort_info {
   EGLint Attribute;
   EGLint MatchCriteria;
   EGLint SortOrder;
};

/* This encodes the info from Table 3.5 of the EGL spec, ordered by
 * Sort Priority.
 */
static struct sort_info SortInfo[] = {
   { EGL_CONFIG_CAVEAT,           EXACT,   SPECIAL },
   { EGL_RED_SIZE,                ATLEAST, SPECIAL },
   { EGL_GREEN_SIZE,              ATLEAST, SPECIAL },
   { EGL_BLUE_SIZE,               ATLEAST, SPECIAL },
   { EGL_ALPHA_SIZE,              ATLEAST, SPECIAL },
   { EGL_BUFFER_SIZE,             ATLEAST, SMALLER },
   { EGL_SAMPLE_BUFFERS,          ATLEAST, SMALLER },
   { EGL_SAMPLES,                 ATLEAST, SMALLER },
   { EGL_DEPTH_SIZE,              ATLEAST, SMALLER },
   { EGL_STENCIL_SIZE,            ATLEAST, SMALLER },
   { EGL_NATIVE_VISUAL_TYPE,      EXACT,   SPECIAL },
   { EGL_CONFIG_ID,               EXACT,   SMALLER },
   { EGL_BIND_TO_TEXTURE_RGB,     EXACT,   NONE    },
   { EGL_BIND_TO_TEXTURE_RGBA,    EXACT,   NONE    },
   { EGL_LEVEL,                   EXACT,   NONE    },
   { EGL_NATIVE_RENDERABLE,       EXACT,   NONE    },
   { EGL_MAX_SWAP_INTERVAL,       EXACT,   NONE    },
   { EGL_MIN_SWAP_INTERVAL,       EXACT,   NONE    },
   { EGL_SURFACE_TYPE,            MASK,    NONE    },
   { EGL_TRANSPARENT_TYPE,        EXACT,   NONE    },
   { EGL_TRANSPARENT_RED_VALUE,   EXACT,   NONE    },
   { EGL_TRANSPARENT_GREEN_VALUE, EXACT,   NONE    },
   { EGL_TRANSPARENT_BLUE_VALUE,  EXACT,   NONE    },
   { 0, 0, 0 }
};


/**
 * Return EGL_TRUE if the attributes of c meet or exceed the minimums
 * specified by min.
 */
EGLBoolean
_eglConfigQualifies(const _EGLConfig *c, const _EGLConfig *min)
{
   EGLint i;
   for (i = 0; SortInfo[i].Attribute != 0; i++) {
      const EGLint mv = GET_CONFIG_ATTRIB(min, SortInfo[i].Attribute);
      if (mv != EGL_DONT_CARE) {
         const EGLint cv = GET_CONFIG_ATTRIB(c, SortInfo[i].Attribute);
         if (SortInfo[i].MatchCriteria == EXACT) {
            if (cv != mv) {
               return EGL_FALSE;
            }
         }
         else if (SortInfo[i].MatchCriteria == ATLEAST) {
            if (cv < mv) {
               return EGL_FALSE;
            }
         }
         else {
            assert(SortInfo[i].MatchCriteria == MASK);
            if ((mv & cv) != mv) {
               return EGL_FALSE;
            }
         }
      }
   }
   return EGL_TRUE;
}


/**
 * Compare configs 'a' and 'b' and return -1 if a belongs before b,
 * 1 if a belongs after b, or 0 if they're equal.
 */
EGLint
_eglCompareConfigs(const _EGLConfig *a, const _EGLConfig *b)
{
   EGLint i;
   for (i = 0; SortInfo[i].Attribute != 0; i++) {
      const EGLint av = GET_CONFIG_ATTRIB(a, SortInfo[i].Attribute);
      const EGLint bv = GET_CONFIG_ATTRIB(b, SortInfo[i].Attribute);
      if (SortInfo[i].SortOrder == SMALLER) {
         if (av < bv)
            return -1;
         else if (av > bv)
            return 1;
         /* else, continue examining attribute values */
      }
      else if (SortInfo[i].SortOrder == SPECIAL) {
         if (SortInfo[i].Attribute == EGL_CONFIG_CAVEAT) {
            /* values are EGL_NONE, SLOW_CONFIG, or NON_CONFORMANT_CONFIG */
            if (av < bv)
               return -1;
            else if (av > bv)
               return 1;
         }
         else if (SortInfo[i].Attribute == EGL_RED_SIZE ||
                  SortInfo[i].Attribute == EGL_GREEN_SIZE ||
                  SortInfo[i].Attribute == EGL_BLUE_SIZE ||
                  SortInfo[i].Attribute == EGL_ALPHA_SIZE) {
            if (av > bv)
               return -1;
            else if (av < bv)
               return 1;
         }
         else {
            assert(SortInfo[i].Attribute == EGL_NATIVE_VISUAL_TYPE);
            if (av < bv)
               return -1;
            else if (av > bv)
               return 1;
         }
      }
      else {
         assert(SortInfo[i].SortOrder == NONE);
         /* continue examining attribute values */
      }
   }
   return 0;
}


/**
 * Typical fallback routine for eglChooseConfig
 */
EGLBoolean
_eglChooseConfig(_EGLDriver *drv, EGLDisplay dpy, const EGLint *attrib_list, EGLConfig *configs, EGLint config_size, EGLint *num_config)
{
   _EGLDisplay *disp = _eglLookupDisplay(dpy);
   _EGLConfig criteria;
   EGLint i;

   /* parse the attrib_list to initialize criteria */
   if (!_eglParseConfigAttribs(&criteria, attrib_list)) {
      return EGL_FALSE;
   }

   *num_config = 0;
   for (i = 0; i < disp->NumConfigs; i++) {
      const _EGLConfig *conf = disp->Configs + i;
      if (_eglConfigQualifies(conf, &criteria)) {
         if (*num_config < config_size) {
            /* save */
            configs[*num_config] = conf->Handle;
            (*num_config)++;
         }
         else {
            break;
         }
      }
   }

   /* XXX sort the list here */

   return EGL_TRUE;
}


/**
 * Fallback for eglGetConfigAttrib.
 */
EGLBoolean
_eglGetConfigAttrib(_EGLDriver *drv, EGLDisplay dpy, EGLConfig config, EGLint attribute, EGLint *value)
{
   const _EGLConfig *conf = _eglLookupConfig(drv, dpy, config);
   const EGLint k = attribute - FIRST_ATTRIB;
   if (k >= 0 && k < MAX_ATTRIBS) {
      *value = conf->Attrib[k];
      return EGL_TRUE;
   }
   else {
      _eglError(EGL_BAD_ATTRIBUTE, "eglGetConfigAttrib");
      return EGL_FALSE;
   }
}


/**
 * Fallback for eglGetConfigs.
 */
EGLBoolean
_eglGetConfigs(_EGLDriver *drv, EGLDisplay dpy, EGLConfig *configs, EGLint config_size, EGLint *num_config)
{
   _EGLDisplay *disp = _eglLookupDisplay(dpy);

   if (!drv->Initialized) {
      _eglError(EGL_NOT_INITIALIZED, "eglGetConfigs");
      return EGL_FALSE;
   }

   if (configs) {
      EGLint i;
      *num_config = MIN2(disp->NumConfigs, config_size);
      for (i = 0; i < *num_config; i++) {
         configs[i] = disp->Configs[i].Handle;
      }
   } else
      *num_config = disp->NumConfigs;
      
   return EGL_TRUE;
}


/**
 * Creates a set of \c __GLcontextModes that a driver will expose.
 * 
 * A set of \c __GLcontextModes will be created based on the supplied
 * parameters.  The number of modes processed will be 2 *
 * \c num_depth_stencil_bits * \c num_db_modes.
 * 
 * For the most part, data is just copied from \c depth_bits, \c stencil_bits,
 * \c db_modes, and \c visType into each \c __GLcontextModes element.
 * However, the meanings of \c fb_format and \c fb_type require further
 * explanation.  The \c fb_format specifies which color components are in
 * each pixel and what the default order is.  For example, \c GL_RGB specifies
 * that red, green, blue are available and red is in the "most significant"
 * position and blue is in the "least significant".  The \c fb_type specifies
 * the bit sizes of each component and the actual ordering.  For example, if
 * \c GL_UNSIGNED_SHORT_5_6_5_REV is specified with \c GL_RGB, bits [15:11]
 * are the blue value, bits [10:5] are the green value, and bits [4:0] are
 * the red value.
 * 
 * One sublte issue is the combination of \c GL_RGB  or \c GL_BGR and either
 * of the \c GL_UNSIGNED_INT_8_8_8_8 modes.  The resulting mask values in the
 * \c __GLcontextModes structure is \b identical to the \c GL_RGBA or
 * \c GL_BGRA case, except the \c alphaMask is zero.  This means that, as
 * far as this routine is concerned, \c GL_RGB with \c GL_UNSIGNED_INT_8_8_8_8
 * still uses 32-bits.
 *
 * If in doubt, look at the tables used in the function.
 * 
 * \param ptr_to_modes  Pointer to a pointer to a linked list of
 *                      \c __GLcontextModes.  Upon completion, a pointer to
 *                      the next element to be process will be stored here.
 *                      If the function fails and returns \c GL_FALSE, this
 *                      value will be unmodified, but some elements in the
 *                      linked list may be modified.
 * \param fb_format     Format of the framebuffer.  Currently only \c GL_RGB,
 *                      \c GL_RGBA, \c GL_BGR, and \c GL_BGRA are supported.
 * \param fb_type       Type of the pixels in the framebuffer.  Currently only
 *                      \c GL_UNSIGNED_SHORT_5_6_5, 
 *                      \c GL_UNSIGNED_SHORT_5_6_5_REV,
 *                      \c GL_UNSIGNED_INT_8_8_8_8, and
 *                      \c GL_UNSIGNED_INT_8_8_8_8_REV are supported.
 * \param depth_bits    Array of depth buffer sizes to be exposed.
 * \param stencil_bits  Array of stencil buffer sizes to be exposed.
 * \param num_depth_stencil_bits  Number of entries in both \c depth_bits and
 *                      \c stencil_bits.
 * \param db_modes      Array of buffer swap modes.  If an element has a
 *                      value of \c GLX_NONE, then it represents a
 *                      single-buffered mode.  Other valid values are
 *                      \c GLX_SWAP_EXCHANGE_OML, \c GLX_SWAP_COPY_OML, and
 *                      \c GLX_SWAP_UNDEFINED_OML.  See the
 *                      GLX_OML_swap_method extension spec for more details.
 * \param num_db_modes  Number of entries in \c db_modes.
 * \param visType       GLX visual type.  Usually either \c GLX_TRUE_COLOR or
 *                      \c GLX_DIRECT_COLOR.
 * 
 * \returns
 * \c GL_TRUE on success or \c GL_FALSE on failure.  Currently the only
 * cause of failure is a bad parameter (i.e., unsupported \c fb_format or
 * \c fb_type).
 * 
 * \todo
 * There is currently no way to support packed RGB modes (i.e., modes with
 * exactly 3 bytes per pixel) or floating-point modes.  This could probably
 * be done by creating some new, private enums with clever names likes
 * \c GL_UNSIGNED_3BYTE_8_8_8, \c GL_4FLOAT_32_32_32_32, 
 * \c GL_4HALF_16_16_16_16, etc.  We can cross that bridge when we come to it.
 */
GLboolean
_eglFillInConfigs(_EGLConfig * configs,
                GLenum fb_format, GLenum fb_type,
                const u_int8_t * depth_bits, const u_int8_t * stencil_bits,
                unsigned num_depth_stencil_bits,
                const GLenum * db_modes, unsigned num_db_modes,
                int visType) {
   static const u_int8_t bits_table[3][4] = {
            /* R  G  B  A */
            { 5, 6, 5, 0 },  /* Any GL_UNSIGNED_SHORT_5_6_5 */
            { 8, 8, 8, 0 },  /* Any RGB with any GL_UNSIGNED_INT_8_8_8_8 */
            { 8, 8, 8, 8 }  /* Any RGBA with any GL_UNSIGNED_INT_8_8_8_8 */
         };

   /* The following arrays are all indexed by the fb_type masked with 0x07.
    * Given the four supported fb_type values, this results in valid array
    * indices of 3, 4, 5, and 7.
    */
   static const u_int32_t masks_table_rgb[8][4] = {
            {0x00000000, 0x00000000, 0x00000000, 0x00000000},
            {0x00000000, 0x00000000, 0x00000000, 0x00000000},
            {0x00000000, 0x00000000, 0x00000000, 0x00000000},
            {0x0000F800, 0x000007E0, 0x0000001F, 0x00000000},  /* 5_6_5       */
            {0x0000001F, 0x000007E0, 0x0000F800, 0x00000000},  /* 5_6_5_REV   */
            {0xFF000000, 0x00FF0000, 0x0000FF00, 0x00000000},  /* 8_8_8_8     */
            {0x00000000, 0x00000000, 0x00000000, 0x00000000},
            {0x000000FF, 0x0000FF00, 0x00FF0000, 0x00000000}  /* 8_8_8_8_REV */
         };

   static const u_int32_t masks_table_rgba[8][4] = {
            {0x00000000, 0x00000000, 0x00000000, 0x00000000},
            {0x00000000, 0x00000000, 0x00000000, 0x00000000},
            {0x00000000, 0x00000000, 0x00000000, 0x00000000},
            {0x0000F800, 0x000007E0, 0x0000001F, 0x00000000},  /* 5_6_5       */
            {0x0000001F, 0x000007E0, 0x0000F800, 0x00000000},  /* 5_6_5_REV   */
            {0xFF000000, 0x00FF0000, 0x0000FF00, 0x000000FF},  /* 8_8_8_8     */
            {0x00000000, 0x00000000, 0x00000000, 0x00000000},
            {0x000000FF, 0x0000FF00, 0x00FF0000, 0xFF000000},  /* 8_8_8_8_REV */
         };

   static const u_int32_t masks_table_bgr[8][4] = {
            {0x00000000, 0x00000000, 0x00000000, 0x00000000},
            {0x00000000, 0x00000000, 0x00000000, 0x00000000},
            {0x00000000, 0x00000000, 0x00000000, 0x00000000},
            {0x0000001F, 0x000007E0, 0x0000F800, 0x00000000},  /* 5_6_5       */
            {0x0000F800, 0x000007E0, 0x0000001F, 0x00000000},  /* 5_6_5_REV   */
            {0x0000FF00, 0x00FF0000, 0xFF000000, 0x00000000},  /* 8_8_8_8     */
            {0x00000000, 0x00000000, 0x00000000, 0x00000000},
            {0x00FF0000, 0x0000FF00, 0x000000FF, 0x00000000},  /* 8_8_8_8_REV */
         };

   static const u_int32_t masks_table_bgra[8][4] = {
            {0x00000000, 0x00000000, 0x00000000, 0x00000000},
            {0x00000000, 0x00000000, 0x00000000, 0x00000000},
            {0x00000000, 0x00000000, 0x00000000, 0x00000000},
            {0x0000001F, 0x000007E0, 0x0000F800, 0x00000000},  /* 5_6_5       */
            {0x0000F800, 0x000007E0, 0x0000001F, 0x00000000},  /* 5_6_5_REV   */
            {0x0000FF00, 0x00FF0000, 0xFF000000, 0x000000FF},  /* 8_8_8_8     */
            {0x00000000, 0x00000000, 0x00000000, 0x00000000},
            {0x00FF0000, 0x0000FF00, 0x000000FF, 0xFF000000},  /* 8_8_8_8_REV */
         };

   static const u_int8_t bytes_per_pixel[8] = {
            0, 0, 0, 2, 2, 4, 0, 4
         };

   const u_int8_t * bits;
   const u_int32_t * masks;
   const int index = fb_type & 0x07;
   _EGLConfig *config;
   unsigned i;
   unsigned j;
   unsigned k;

   if ( bytes_per_pixel[index] == 0 ) {
      _eglLog(_EGL_INFO,
              "[%s:%u] Framebuffer type 0x%04x has 0 bytes per pixel.",
              __FUNCTION__, __LINE__, fb_type);
      return GL_FALSE;
   }

   /* Valid types are GL_UNSIGNED_SHORT_5_6_5 and GL_UNSIGNED_INT_8_8_8_8 and
    * the _REV versions.
    *
    * Valid formats are GL_RGBA, GL_RGB, and GL_BGRA.
    */
   switch ( fb_format ) {
   case GL_RGB:
      bits = (bytes_per_pixel[index] == 2) ? bits_table[0] : bits_table[1];
      masks = masks_table_rgb[index];
      break;

   case GL_RGBA:
      bits = (bytes_per_pixel[index] == 2) ? bits_table[0] : bits_table[2];
      masks = masks_table_rgba[index];
      break;

   case GL_BGR:
      bits = (bytes_per_pixel[index] == 2) ? bits_table[0] : bits_table[1];
      masks = masks_table_bgr[index];
      break;

   case GL_BGRA:
      bits = (bytes_per_pixel[index] == 2) ? bits_table[0] : bits_table[2];
      masks = masks_table_bgra[index];
      break;

   default:
      _eglLog(_EGL_WARNING,
              "[%s:%u] Framebuffer format 0x%04x is not GL_RGB, GL_RGBA, GL_BGR, or GL_BGRA.",
              __FUNCTION__, __LINE__, fb_format);
      return GL_FALSE;
   }

   config = configs;
   for (k = 0; k < num_depth_stencil_bits; k++) {
      for (i = 0; i < num_db_modes; i++)  {
         for (j = 0; j < 2; j++) {
            _eglSetConfigAttrib(config, EGL_RED_SIZE, bits[0]);
            _eglSetConfigAttrib(config, EGL_GREEN_SIZE, bits[1]);
            _eglSetConfigAttrib(config, EGL_BLUE_SIZE, bits[2]);
            _eglSetConfigAttrib(config, EGL_ALPHA_SIZE, bits[3]);
            _eglSetConfigAttrib(config, EGL_BUFFER_SIZE,
                                bits[0] + bits[1] + bits[2] + bits[3]);

            _eglSetConfigAttrib(config, EGL_STENCIL_SIZE, stencil_bits[k]);
            _eglSetConfigAttrib(config, EGL_DEPTH_SIZE, depth_bits[i]);

            _eglSetConfigAttrib(config, EGL_SURFACE_TYPE, EGL_SCREEN_BIT_MESA |
                         EGL_PBUFFER_BIT | EGL_PIXMAP_BIT | EGL_WINDOW_BIT);

            config++;
         }
      }
   }
   return GL_TRUE;
}