src/egl/main/eglconfig.c

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