src/egl/main/eglconfig.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2008 VMware, Inc.
   4  * Copyright 2009-2010 Chia-I Wu <olvaffe@gmail.com>
   5  * Copyright 2010-2011 LunarG, Inc.
   6  * All Rights Reserved.
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a
   9  * copy of this software and associated documentation files (the
  10  * "Software"), to deal in the Software without restriction, including
  11  * without limitation the rights to use, copy, modify, merge, publish,
  12  * distribute, sub license, and/or sell copies of the Software, and to
  13  * permit persons to whom the Software is furnished to do so, subject to
  14  * the following conditions:
  15  *
  16  * The above copyright notice and this permission notice (including the
  17  * next paragraph) shall be included in all copies or substantial portions
  18  * of the Software.
  19  *
  20  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  21  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  23  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  24  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  25  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  26  * DEALINGS IN THE SOFTWARE.
  27  *
  28  **************************************************************************/
  29
  30
  31 /**
  32  * EGL Configuration (pixel format) functions.
  33  */
  34
  35
  36 #include <stdlib.h>
  37 #include <string.h>
  38 #include <assert.h>
  39 #include "c99_compat.h"
  40
  41 #include "eglconfig.h"
  42 #include "egldisplay.h"
  43 #include "eglcurrent.h"
  44 #include "egllog.h"
  45
  46
  47 #define MIN2(A, B)  (((A) < (B)) ? (A) : (B))
  48
  49
  50 /**
  51  * Init the given _EGLconfig to default values.
  52  * \param id  the configuration's ID.
  53  *
  54  * Note that id must be positive for the config to be valid.
  55  * It is also recommended that when there are N configs, their
  56  * IDs are from 1 to N respectively.
  57  */
  58 void
  59 _eglInitConfig(_EGLConfig *conf, _EGLDisplay *dpy, EGLint id)
  60 {
  61    memset(conf, 0, sizeof(*conf));
  62
  63    conf->Display = dpy;
  64
  65    /* some attributes take non-zero default values */
  66    conf->ConfigID = id;
  67    conf->ConfigCaveat = EGL_NONE;
  68    conf->TransparentType = EGL_NONE;
  69    conf->NativeVisualType = EGL_NONE;
  70    conf->ColorBufferType = EGL_RGB_BUFFER;
  71 }
  72
  73
  74 /**
  75  * Link a config to its display and return the handle of the link.
  76  * The handle can be passed to client directly.
  77  *
  78  * Note that we just save the ptr to the config (we don't copy the config).
  79  */
  80 PUBLIC EGLConfig
  81 _eglLinkConfig(_EGLConfig *conf)
  82 {
  83    _EGLDisplay *dpy = conf->Display;
  84
  85    /* sanity check */
  86    assert(dpy && conf->ConfigID > 0);
  87
  88    if (!dpy->Configs) {
  89       dpy->Configs = _eglCreateArray("Config", 16);
  90       if (!dpy->Configs)
  91          return (EGLConfig) NULL;
  92    }
  93
  94    _eglAppendArray(dpy->Configs, (void *) conf);
  95
  96    return (EGLConfig) conf;
  97 }
  98
  99
 100 /**
 101  * Lookup a handle to find the linked config.
 102  * Return NULL if the handle has no corresponding linked config.
 103  */
 104 _EGLConfig *
 105 _eglLookupConfig(EGLConfig config, _EGLDisplay *dpy)
 106 {
 107    _EGLConfig *conf;
 108
 109    if (!dpy)
 110       return NULL;
 111
 112    conf = (_EGLConfig *) _eglFindArray(dpy->Configs, (void *) config);
 113    if (conf)
 114       assert(conf->Display == dpy);
 115
 116    return conf;
 117 }
 118
 119
 120 enum {
 121    /* types */
 122    ATTRIB_TYPE_INTEGER,
 123    ATTRIB_TYPE_BOOLEAN,
 124    ATTRIB_TYPE_BITMASK,
 125    ATTRIB_TYPE_ENUM,
 126    ATTRIB_TYPE_PSEUDO, /* non-queryable */
 127    ATTRIB_TYPE_PLATFORM, /* platform-dependent */
 128    /* criteria */
 129    ATTRIB_CRITERION_EXACT,
 130    ATTRIB_CRITERION_ATLEAST,
 131    ATTRIB_CRITERION_MASK,
 132    ATTRIB_CRITERION_SPECIAL,
 133    ATTRIB_CRITERION_IGNORE
 134 };
 135
 136
 137 /* EGL spec Table 3.1 and 3.4 */
 138 static const struct {
 139    EGLint attr;
 140    EGLint type;
 141    EGLint criterion;
 142    EGLint default_value;
 143 } _eglValidationTable[] =
 144 {
 145    /* core */
 146    { EGL_BUFFER_SIZE,               ATTRIB_TYPE_INTEGER,
 147                                     ATTRIB_CRITERION_ATLEAST,
 148                                     0 },
 149    { EGL_RED_SIZE,                  ATTRIB_TYPE_INTEGER,
 150                                     ATTRIB_CRITERION_ATLEAST,
 151                                     0 },
 152    { EGL_GREEN_SIZE,                ATTRIB_TYPE_INTEGER,
 153                                     ATTRIB_CRITERION_ATLEAST,
 154                                     0 },
 155    { EGL_BLUE_SIZE,                 ATTRIB_TYPE_INTEGER,
 156                                     ATTRIB_CRITERION_ATLEAST,
 157                                     0 },
 158    { EGL_LUMINANCE_SIZE,            ATTRIB_TYPE_INTEGER,
 159                                     ATTRIB_CRITERION_ATLEAST,
 160                                     0 },
 161    { EGL_ALPHA_SIZE,                ATTRIB_TYPE_INTEGER,
 162                                     ATTRIB_CRITERION_ATLEAST,
 163                                     0 },
 164    { EGL_ALPHA_MASK_SIZE,           ATTRIB_TYPE_INTEGER,
 165                                     ATTRIB_CRITERION_ATLEAST,
 166                                     0 },
 167    { EGL_BIND_TO_TEXTURE_RGB,       ATTRIB_TYPE_BOOLEAN,
 168                                     ATTRIB_CRITERION_EXACT,
 169                                     EGL_DONT_CARE },
 170    { EGL_BIND_TO_TEXTURE_RGBA,      ATTRIB_TYPE_BOOLEAN,
 171                                     ATTRIB_CRITERION_EXACT,
 172                                     EGL_DONT_CARE },
 173    { EGL_COLOR_BUFFER_TYPE,         ATTRIB_TYPE_ENUM,
 174                                     ATTRIB_CRITERION_EXACT,
 175                                     EGL_RGB_BUFFER },
 176    { EGL_CONFIG_CAVEAT,             ATTRIB_TYPE_ENUM,
 177                                     ATTRIB_CRITERION_EXACT,
 178                                     EGL_DONT_CARE },
 179    { EGL_CONFIG_ID,                 ATTRIB_TYPE_INTEGER,
 180                                     ATTRIB_CRITERION_EXACT,
 181                                     EGL_DONT_CARE },
 182    { EGL_CONFORMANT,                ATTRIB_TYPE_BITMASK,
 183                                     ATTRIB_CRITERION_MASK,
 184                                     0 },
 185    { EGL_DEPTH_SIZE,                ATTRIB_TYPE_INTEGER,
 186                                     ATTRIB_CRITERION_ATLEAST,
 187                                     0 },
 188    { EGL_LEVEL,                     ATTRIB_TYPE_PLATFORM,
 189                                     ATTRIB_CRITERION_EXACT,
 190                                     0 },
 191    { EGL_MAX_PBUFFER_WIDTH,         ATTRIB_TYPE_INTEGER,
 192                                     ATTRIB_CRITERION_IGNORE,
 193                                     0 },
 194    { EGL_MAX_PBUFFER_HEIGHT,        ATTRIB_TYPE_INTEGER,
 195                                     ATTRIB_CRITERION_IGNORE,
 196                                     0 },
 197    { EGL_MAX_PBUFFER_PIXELS,        ATTRIB_TYPE_INTEGER,
 198                                     ATTRIB_CRITERION_IGNORE,
 199                                     0 },
 200    { EGL_MAX_SWAP_INTERVAL,         ATTRIB_TYPE_INTEGER,
 201                                     ATTRIB_CRITERION_EXACT,
 202                                     EGL_DONT_CARE },
 203    { EGL_MIN_SWAP_INTERVAL,         ATTRIB_TYPE_INTEGER,
 204                                     ATTRIB_CRITERION_EXACT,
 205                                     EGL_DONT_CARE },
 206    { EGL_NATIVE_RENDERABLE,         ATTRIB_TYPE_BOOLEAN,
 207                                     ATTRIB_CRITERION_EXACT,
 208                                     EGL_DONT_CARE },
 209    { EGL_NATIVE_VISUAL_ID,          ATTRIB_TYPE_PLATFORM,
 210                                     ATTRIB_CRITERION_IGNORE,
 211                                     0 },
 212    { EGL_NATIVE_VISUAL_TYPE,        ATTRIB_TYPE_PLATFORM,
 213                                     ATTRIB_CRITERION_EXACT,
 214                                     EGL_DONT_CARE },
 215    { EGL_RENDERABLE_TYPE,           ATTRIB_TYPE_BITMASK,
 216                                     ATTRIB_CRITERION_MASK,
 217                                     EGL_OPENGL_ES_BIT },
 218    { EGL_SAMPLE_BUFFERS,            ATTRIB_TYPE_INTEGER,
 219                                     ATTRIB_CRITERION_ATLEAST,
 220                                     0 },
 221    { EGL_SAMPLES,                   ATTRIB_TYPE_INTEGER,
 222                                     ATTRIB_CRITERION_ATLEAST,
 223                                     0 },
 224    { EGL_STENCIL_SIZE,              ATTRIB_TYPE_INTEGER,
 225                                     ATTRIB_CRITERION_ATLEAST,
 226                                     0 },
 227    { EGL_SURFACE_TYPE,              ATTRIB_TYPE_BITMASK,
 228                                     ATTRIB_CRITERION_MASK,
 229                                     EGL_WINDOW_BIT },
 230    { EGL_TRANSPARENT_TYPE,          ATTRIB_TYPE_ENUM,
 231                                     ATTRIB_CRITERION_EXACT,
 232                                     EGL_NONE },
 233    { EGL_TRANSPARENT_RED_VALUE,     ATTRIB_TYPE_INTEGER,
 234                                     ATTRIB_CRITERION_EXACT,
 235                                     EGL_DONT_CARE },
 236    { EGL_TRANSPARENT_GREEN_VALUE,   ATTRIB_TYPE_INTEGER,
 237                                     ATTRIB_CRITERION_EXACT,
 238                                     EGL_DONT_CARE },
 239    { EGL_TRANSPARENT_BLUE_VALUE,    ATTRIB_TYPE_INTEGER,
 240                                     ATTRIB_CRITERION_EXACT,
 241                                     EGL_DONT_CARE },
 242    { EGL_MATCH_NATIVE_PIXMAP,       ATTRIB_TYPE_PSEUDO,
 243                                     ATTRIB_CRITERION_SPECIAL,
 244                                     EGL_NONE },
 245    /* extensions */
 246    { EGL_Y_INVERTED_NOK,            ATTRIB_TYPE_BOOLEAN,
 247                                     ATTRIB_CRITERION_EXACT,
 248                                     EGL_DONT_CARE }
 249 };
 250
 251
 252 /**
 253  * Return true if a config is valid.  When for_matching is true,
 254  * EGL_DONT_CARE is accepted as a valid attribute value, and checks
 255  * for conflicting attribute values are skipped.
 256  *
 257  * Note that some attributes are platform-dependent and are not
 258  * checked.
 259  */
 260 EGLBoolean
 261 _eglValidateConfig(const _EGLConfig *conf, EGLBoolean for_matching)
 262 {
 263    EGLint i, attr, val;
 264    EGLBoolean valid = EGL_TRUE;
 265
 266    /* check attributes by their types */
 267    for (i = 0; i < ARRAY_SIZE(_eglValidationTable); i++) {
 268       EGLint mask;
 269
 270       attr = _eglValidationTable[i].attr;
 271       val = _eglGetConfigKey(conf, attr);
 272
 273       switch (_eglValidationTable[i].type) {
 274       case ATTRIB_TYPE_INTEGER:
 275          switch (attr) {
 276          case EGL_CONFIG_ID:
 277             /* config id must be positive */
 278             if (val <= 0)
 279                valid = EGL_FALSE;
 280             break;
 281          case EGL_SAMPLE_BUFFERS:
 282             /* there can be at most 1 sample buffer */
 283             if (val > 1 || val < 0)
 284                valid = EGL_FALSE;
 285             break;
 286          default:
 287             if (val < 0)
 288                valid = EGL_FALSE;
 289             break;
 290          }
 291          break;
 292       case ATTRIB_TYPE_BOOLEAN:
 293          if (val != EGL_TRUE && val != EGL_FALSE)
 294             valid = EGL_FALSE;
 295          break;
 296       case ATTRIB_TYPE_ENUM:
 297          switch (attr) {
 298          case EGL_CONFIG_CAVEAT:
 299             if (val != EGL_NONE && val != EGL_SLOW_CONFIG &&
 300                 val != EGL_NON_CONFORMANT_CONFIG)
 301                valid = EGL_FALSE;
 302             break;
 303          case EGL_TRANSPARENT_TYPE:
 304             if (val != EGL_NONE && val != EGL_TRANSPARENT_RGB)
 305                valid = EGL_FALSE;
 306             break;
 307          case EGL_COLOR_BUFFER_TYPE:
 308             if (val != EGL_RGB_BUFFER && val != EGL_LUMINANCE_BUFFER)
 309                valid = EGL_FALSE;
 310             break;
 311          default:
 312             assert(0);
 313             break;
 314          }
 315          break;
 316       case ATTRIB_TYPE_BITMASK:
 317          switch (attr) {
 318          case EGL_SURFACE_TYPE:
 319             mask = EGL_PBUFFER_BIT |
 320                    EGL_PIXMAP_BIT |
 321                    EGL_WINDOW_BIT |
 322                    EGL_VG_COLORSPACE_LINEAR_BIT |
 323                    EGL_VG_ALPHA_FORMAT_PRE_BIT |
 324                    EGL_MULTISAMPLE_RESOLVE_BOX_BIT |
 325                    EGL_SWAP_BEHAVIOR_PRESERVED_BIT;
 326 #ifdef EGL_MESA_screen_surface
 327             if (conf->Display->Extensions.MESA_screen_surface)
 328                mask |= EGL_SCREEN_BIT_MESA;
 329 #endif
 330             break;
 331          case EGL_RENDERABLE_TYPE:
 332          case EGL_CONFORMANT:
 333             mask = EGL_OPENGL_ES_BIT |
 334                    EGL_OPENVG_BIT |
 335                    EGL_OPENGL_ES2_BIT |
 336                    EGL_OPENGL_ES3_BIT_KHR |
 337                    EGL_OPENGL_BIT;
 338             break;
 339          default:
 340             assert(0);
 341             mask = 0;
 342             break;
 343          }
 344          if (val & ~mask)
 345             valid = EGL_FALSE;
 346          break;
 347       case ATTRIB_TYPE_PLATFORM:
 348          /* unable to check platform-dependent attributes here */
 349          break;
 350       case ATTRIB_TYPE_PSEUDO:
 351          /* pseudo attributes should not be set */
 352          if (val != 0)
 353             valid = EGL_FALSE;
 354          break;
 355       default:
 356          assert(0);
 357          break;
 358       }
 359
 360       if (!valid && for_matching) {
 361          /* accept EGL_DONT_CARE as a valid value */
 362          if (val == EGL_DONT_CARE)
 363             valid = EGL_TRUE;
 364          if (_eglValidationTable[i].criterion == ATTRIB_CRITERION_SPECIAL)
 365             valid = EGL_TRUE;
 366       }
 367       if (!valid) {
 368          _eglLog(_EGL_DEBUG,
 369                "attribute 0x%04x has an invalid value 0x%x", attr, val);
 370          break;
 371       }
 372    }
 373
 374    /* any invalid attribute value should have been catched */
 375    if (!valid || for_matching)
 376       return valid;
 377
 378    /* now check for conflicting attribute values */
 379
 380    switch (conf->ColorBufferType) {
 381    case EGL_RGB_BUFFER:
 382       if (conf->LuminanceSize)
 383          valid = EGL_FALSE;
 384       if (conf->RedSize + conf->GreenSize +
 385             conf->BlueSize + conf->AlphaSize != conf->BufferSize)
 386          valid = EGL_FALSE;
 387       break;
 388    case EGL_LUMINANCE_BUFFER:
 389       if (conf->RedSize || conf->GreenSize || conf->BlueSize)
 390          valid = EGL_FALSE;
 391       if (conf->LuminanceSize + conf->AlphaSize != conf->BufferSize)
 392          valid = EGL_FALSE;
 393       break;
 394    }
 395    if (!valid) {
 396       _eglLog(_EGL_DEBUG, "conflicting color buffer type and channel sizes");
 397       return EGL_FALSE;
 398    }
 399
 400    if (!conf->SampleBuffers && conf->Samples)
 401       valid = EGL_FALSE;
 402    if (!valid) {
 403       _eglLog(_EGL_DEBUG, "conflicting samples and sample buffers");
 404       return EGL_FALSE;
 405    }
 406
 407    if (!(conf->SurfaceType & EGL_WINDOW_BIT)) {
 408       if (conf->NativeVisualID != 0 || conf->NativeVisualType != EGL_NONE)
 409          valid = EGL_FALSE;
 410    }
 411    if (!(conf->SurfaceType & EGL_PBUFFER_BIT)) {
 412       if (conf->BindToTextureRGB || conf->BindToTextureRGBA)
 413          valid = EGL_FALSE;
 414    }
 415    if (!valid) {
 416       _eglLog(_EGL_DEBUG, "conflicting surface type and native visual/texture binding");
 417       return EGL_FALSE;
 418    }
 419
 420    return valid;
 421 }
 422
 423
 424 /**
 425  * Return true if a config matches the criteria.  This and
 426  * _eglParseConfigAttribList together implement the algorithm
 427  * described in "Selection of EGLConfigs".
 428  *
 429  * Note that attributes that are special (currently, only
 430  * EGL_MATCH_NATIVE_PIXMAP) are ignored.
 431  */
 432 EGLBoolean
 433 _eglMatchConfig(const _EGLConfig *conf, const _EGLConfig *criteria)
 434 {
 435    EGLint attr, val, i;
 436    EGLBoolean matched = EGL_TRUE;
 437
 438    for (i = 0; i < ARRAY_SIZE(_eglValidationTable); i++) {
 439       EGLint cmp;
 440       if (_eglValidationTable[i].criterion == ATTRIB_CRITERION_IGNORE)
 441          continue;
 442
 443       attr = _eglValidationTable[i].attr;
 444       cmp = _eglGetConfigKey(criteria, attr);
 445       if (cmp == EGL_DONT_CARE)
 446          continue;
 447
 448       val = _eglGetConfigKey(conf, attr);
 449       switch (_eglValidationTable[i].criterion) {
 450       case ATTRIB_CRITERION_EXACT:
 451          if (val != cmp)
 452             matched = EGL_FALSE;
 453          break;
 454       case ATTRIB_CRITERION_ATLEAST:
 455          if (val < cmp)
 456             matched = EGL_FALSE;
 457          break;
 458       case ATTRIB_CRITERION_MASK:
 459          if ((val & cmp) != cmp)
 460             matched = EGL_FALSE;
 461          break;
 462       case ATTRIB_CRITERION_SPECIAL:
 463          /* ignored here */
 464          break;
 465       default:
 466          assert(0);
 467          break;
 468       }
 469
 470       if (!matched) {
 471 #ifndef DEBUG
 472          /* only print the common errors when DEBUG is not defined */
 473          if (attr != EGL_RENDERABLE_TYPE)
 474             break;
 475 #endif
 476          _eglLog(_EGL_DEBUG,
 477                "the value (0x%x) of attribute 0x%04x did not meet the criteria (0x%x)",
 478                val, attr, cmp);
 479          break;
 480       }
 481    }
 482
 483    return matched;
 484 }
 485
 486 static inline EGLBoolean
 487 _eglIsConfigAttribValid(_EGLConfig *conf, EGLint attr)
 488 {
 489    if (_eglOffsetOfConfig(attr) < 0)
 490       return EGL_FALSE;
 491
 492    switch (attr) {
 493    case EGL_Y_INVERTED_NOK:
 494       return conf->Display->Extensions.NOK_texture_from_pixmap;
 495    default:
 496       break;
 497    }
 498
 499    return EGL_TRUE;
 500 }
 501
 502 /**
 503  * Initialize a criteria config from the given attribute list.
 504  * Return EGL_FALSE if any of the attribute is invalid.
 505  */
 506 EGLBoolean
 507 _eglParseConfigAttribList(_EGLConfig *conf, _EGLDisplay *dpy,
 508                           const EGLint *attrib_list)
 509 {
 510    EGLint attr, val, i;
 511
 512    _eglInitConfig(conf, dpy, EGL_DONT_CARE);
 513
 514    /* reset to default values */
 515    for (i = 0; i < ARRAY_SIZE(_eglValidationTable); i++) {
 516       attr = _eglValidationTable[i].attr;
 517       val = _eglValidationTable[i].default_value;
 518       _eglSetConfigKey(conf, attr, val);
 519    }
 520
 521    /* parse the list */
 522    for (i = 0; attrib_list && attrib_list[i] != EGL_NONE; i += 2) {
 523       attr = attrib_list[i];
 524       val = attrib_list[i + 1];
 525
 526       if (!_eglIsConfigAttribValid(conf, attr))
 527          return EGL_FALSE;
 528
 529       _eglSetConfigKey(conf, attr, val);
 530    }
 531
 532    if (!_eglValidateConfig(conf, EGL_TRUE))
 533       return EGL_FALSE;
 534
 535    /* EGL_LEVEL and EGL_MATCH_NATIVE_PIXMAP cannot be EGL_DONT_CARE */
 536    if (conf->Level == EGL_DONT_CARE ||
 537        conf->MatchNativePixmap == EGL_DONT_CARE)
 538       return EGL_FALSE;
 539
 540    /* ignore other attributes when EGL_CONFIG_ID is given */
 541    if (conf->ConfigID != EGL_DONT_CARE) {
 542       for (i = 0; i < ARRAY_SIZE(_eglValidationTable); i++) {
 543          attr = _eglValidationTable[i].attr;
 544          if (attr != EGL_CONFIG_ID)
 545             _eglSetConfigKey(conf, attr, EGL_DONT_CARE);
 546       }
 547    }
 548    else {
 549       if (!(conf->SurfaceType & EGL_WINDOW_BIT))
 550          conf->NativeVisualType = EGL_DONT_CARE;
 551
 552       if (conf->TransparentType == EGL_NONE) {
 553          conf->TransparentRedValue = EGL_DONT_CARE;
 554          conf->TransparentGreenValue = EGL_DONT_CARE;
 555          conf->TransparentBlueValue = EGL_DONT_CARE;
 556       }
 557    }
 558
 559    return EGL_TRUE;
 560 }
 561
 562
 563 /**
 564  * Decide the ordering of conf1 and conf2, under the given criteria.
 565  * When compare_id is true, this implements the algorithm described
 566  * in "Sorting of EGLConfigs".  When compare_id is false,
 567  * EGL_CONFIG_ID is not compared.
 568  *
 569  * It returns a negative integer if conf1 is considered to come
 570  * before conf2;  a positive integer if conf2 is considered to come
 571  * before conf1;  zero if the ordering cannot be decided.
 572  *
 573  * Note that EGL_NATIVE_VISUAL_TYPE is platform-dependent and is
 574  * ignored here.
 575  */
 576 EGLint
 577 _eglCompareConfigs(const _EGLConfig *conf1, const _EGLConfig *conf2,
 578                    const _EGLConfig *criteria, EGLBoolean compare_id)
 579 {
 580    const EGLint compare_attribs[] = {
 581       EGL_BUFFER_SIZE,
 582       EGL_SAMPLE_BUFFERS,
 583       EGL_SAMPLES,
 584       EGL_DEPTH_SIZE,
 585       EGL_STENCIL_SIZE,
 586       EGL_ALPHA_MASK_SIZE,
 587    };
 588    EGLint val1, val2;
 589    EGLint i;
 590
 591    if (conf1 == conf2)
 592       return 0;
 593
 594    /* the enum values have the desired ordering */
 595    assert(EGL_NONE < EGL_SLOW_CONFIG);
 596    assert(EGL_SLOW_CONFIG < EGL_NON_CONFORMANT_CONFIG);
 597    val1 = conf1->ConfigCaveat - conf2->ConfigCaveat;
 598    if (val1)
 599       return val1;
 600
 601    /* the enum values have the desired ordering */
 602    assert(EGL_RGB_BUFFER < EGL_LUMINANCE_BUFFER);
 603    val1 = conf1->ColorBufferType - conf2->ColorBufferType;
 604    if (val1)
 605       return val1;
 606
 607    if (criteria) {
 608       val1 = val2 = 0;
 609       if (conf1->ColorBufferType == EGL_RGB_BUFFER) {
 610          if (criteria->RedSize > 0) {
 611             val1 += conf1->RedSize;
 612             val2 += conf2->RedSize;
 613          }
 614          if (criteria->GreenSize > 0) {
 615             val1 += conf1->GreenSize;
 616             val2 += conf2->GreenSize;
 617          }
 618          if (criteria->BlueSize > 0) {
 619             val1 += conf1->BlueSize;
 620             val2 += conf2->BlueSize;
 621          }
 622       }
 623       else {
 624          if (criteria->LuminanceSize > 0) {
 625             val1 += conf1->LuminanceSize;
 626             val2 += conf2->LuminanceSize;
 627          }
 628       }
 629       if (criteria->AlphaSize > 0) {
 630          val1 += conf1->AlphaSize;
 631          val2 += conf2->AlphaSize;
 632       }
 633    }
 634    else {
 635       /* assume the default criteria, which gives no specific ordering */
 636       val1 = val2 = 0;
 637    }
 638
 639    /* for color bits, larger one is preferred */
 640    if (val1 != val2)
 641       return (val2 - val1);
 642
 643    for (i = 0; i < ARRAY_SIZE(compare_attribs); i++) {
 644       val1 = _eglGetConfigKey(conf1, compare_attribs[i]);
 645       val2 = _eglGetConfigKey(conf2, compare_attribs[i]);
 646       if (val1 != val2)
 647          return (val1 - val2);
 648    }
 649
 650    /* EGL_NATIVE_VISUAL_TYPE cannot be compared here */
 651
 652    return (compare_id) ? (conf1->ConfigID - conf2->ConfigID) : 0;
 653 }
 654
 655
 656 static inline
 657 void _eglSwapConfigs(const _EGLConfig **conf1, const _EGLConfig **conf2)
 658 {
 659    const _EGLConfig *tmp = *conf1;
 660    *conf1 = *conf2;
 661    *conf2 = tmp;
 662 }
 663
 664
 665 /**
 666  * Quick sort an array of configs.  This differs from the standard
 667  * qsort() in that the compare function accepts an additional
 668  * argument.
 669  */
 670 static void
 671 _eglSortConfigs(const _EGLConfig **configs, EGLint count,
 672                 EGLint (*compare)(const _EGLConfig *, const _EGLConfig *,
 673                                   void *),
 674                 void *priv_data)
 675 {
 676    const EGLint pivot = 0;
 677    EGLint i, j;
 678
 679    if (count <= 1)
 680       return;
 681
 682    _eglSwapConfigs(&configs[pivot], &configs[count / 2]);
 683    i = 1;
 684    j = count - 1;
 685    do {
 686       while (i < count && compare(configs[i], configs[pivot], priv_data) < 0)
 687          i++;
 688       while (compare(configs[j], configs[pivot], priv_data) > 0)
 689          j--;
 690       if (i < j) {
 691          _eglSwapConfigs(&configs[i], &configs[j]);
 692          i++;
 693          j--;
 694       }
 695       else if (i == j) {
 696          i++;
 697          j--;
 698          break;
 699       }
 700    } while (i <= j);
 701    _eglSwapConfigs(&configs[pivot], &configs[j]);
 702
 703    _eglSortConfigs(configs, j, compare, priv_data);
 704    _eglSortConfigs(configs + i, count - i, compare, priv_data);
 705 }
 706
 707
 708 /**
 709  * A helper function for implementing eglChooseConfig.  See _eglFilterArray and
 710  * _eglSortConfigs for the meanings of match and compare.
 711  */
 712 EGLBoolean
 713 _eglFilterConfigArray(_EGLArray *array, EGLConfig *configs,
 714                       EGLint config_size, EGLint *num_configs,
 715                       EGLBoolean (*match)(const _EGLConfig *, void *),
 716                       EGLint (*compare)(const _EGLConfig *, const _EGLConfig *,
 717                                         void *),
 718                       void *priv_data)
 719 {
 720    _EGLConfig **configList;
 721    EGLint i, count;
 722
 723    if (!num_configs)
 724       return _eglError(EGL_BAD_PARAMETER, "eglChooseConfigs");
 725
 726    /* get the number of matched configs */
 727    count = _eglFilterArray(array, NULL, 0,
 728          (_EGLArrayForEach) match, priv_data);
 729    if (!count) {
 730       *num_configs = count;
 731       return EGL_TRUE;
 732    }
 733
 734    configList = malloc(sizeof(*configList) * count);
 735    if (!configList)
 736       return _eglError(EGL_BAD_ALLOC, "eglChooseConfig(out of memory)");
 737
 738    /* get the matched configs */
 739    _eglFilterArray(array, (void **) configList, count,
 740          (_EGLArrayForEach) match, priv_data);
 741
 742    /* perform sorting of configs */
 743    if (configs && count) {
 744       _eglSortConfigs((const _EGLConfig **) configList, count,
 745                       compare, priv_data);
 746       count = MIN2(count, config_size);
 747       for (i = 0; i < count; i++)
 748          configs[i] = _eglGetConfigHandle(configList[i]);
 749    }
 750
 751    free(configList);
 752
 753    *num_configs = count;
 754
 755    return EGL_TRUE;
 756 }
 757
 758
 759 static EGLBoolean
 760 _eglFallbackMatch(const _EGLConfig *conf, void *priv_data)
 761 {
 762    return _eglMatchConfig(conf, (const _EGLConfig *) priv_data);
 763 }
 764
 765
 766 static EGLint
 767 _eglFallbackCompare(const _EGLConfig *conf1, const _EGLConfig *conf2,
 768                     void *priv_data)
 769 {
 770    return _eglCompareConfigs(conf1, conf2,
 771          (const _EGLConfig *) priv_data, EGL_TRUE);
 772 }
 773
 774
 775 /**
 776  * Typical fallback routine for eglChooseConfig
 777  */
 778 EGLBoolean
 779 _eglChooseConfig(_EGLDriver *drv, _EGLDisplay *disp, const EGLint *attrib_list,
 780                  EGLConfig *configs, EGLint config_size, EGLint *num_configs)
 781 {
 782    _EGLConfig criteria;
 783
 784    if (!_eglParseConfigAttribList(&criteria, disp, attrib_list))
 785       return _eglError(EGL_BAD_ATTRIBUTE, "eglChooseConfig");
 786
 787    return _eglFilterConfigArray(disp->Configs,
 788          configs, config_size, num_configs,
 789          _eglFallbackMatch, _eglFallbackCompare,
 790          (void *) &criteria);
 791 }
 792
 793
 794 /**
 795  * Fallback for eglGetConfigAttrib.
 796  */
 797 EGLBoolean
 798 _eglGetConfigAttrib(_EGLDriver *drv, _EGLDisplay *dpy, _EGLConfig *conf,
 799                     EGLint attribute, EGLint *value)
 800 {
 801    if (!_eglIsConfigAttribValid(conf, attribute))
 802       return _eglError(EGL_BAD_ATTRIBUTE, "eglGetConfigAttrib");
 803
 804    /* nonqueryable attributes */
 805    switch (attribute) {
 806    case EGL_MATCH_NATIVE_PIXMAP:
 807       return _eglError(EGL_BAD_ATTRIBUTE, "eglGetConfigAttrib");
 808       break;
 809    default:
 810       break;
 811    }
 812
 813    if (!value)
 814       return _eglError(EGL_BAD_PARAMETER, "eglGetConfigAttrib");
 815
 816    *value = _eglGetConfigKey(conf, attribute);
 817    return EGL_TRUE;
 818 }
 819
 820
 821 static EGLBoolean
 822 _eglFlattenConfig(void *elem, void *buffer)
 823 {
 824    _EGLConfig *conf = (_EGLConfig *) elem;
 825    EGLConfig *handle = (EGLConfig *) buffer;
 826    *handle = _eglGetConfigHandle(conf);
 827    return EGL_TRUE;
 828 }
 829
 830 /**
 831  * Fallback for eglGetConfigs.
 832  */
 833 EGLBoolean
 834 _eglGetConfigs(_EGLDriver *drv, _EGLDisplay *disp, EGLConfig *configs,
 835                EGLint config_size, EGLint *num_config)
 836 {
 837    if (!num_config)
 838       return _eglError(EGL_BAD_PARAMETER, "eglGetConfigs");
 839
 840    *num_config = _eglFlattenArray(disp->Configs, (void *) configs,
 841          sizeof(configs[0]), config_size, _eglFlattenConfig);
 842
 843    return EGL_TRUE;
 844 }