src/video/SDL_egl.c
author Ryan C. Gordon <icculus@icculus.org>
Wed, 06 Sep 2017 19:34:23 -0400
changeset 11462 dc5698982bac
parent 11418 7749a3b2b343
child 11516 68a767ae3a88
permissions -rw-r--r--
raspberrypi: The latest Raspbian moved its EGL and GLES2 libs elsewhere.

Now we try the new (hardware-specific) pathnames first, and if those fail to
load, we'll try the more generic names that earlier versions of Raspbian used.

Fixes Bugzilla #3800.
     1 /*
     2  *  Simple DirectMedia Layer
     3  *  Copyright (C) 1997-2017 Sam Lantinga <slouken@libsdl.org>
     4  * 
     5  *  This software is provided 'as-is', without any express or implied
     6  *  warranty.  In no event will the authors be held liable for any damages
     7  *  arising from the use of this software.
     8  * 
     9  *  Permission is granted to anyone to use this software for any purpose,
    10  *  including commercial applications, and to alter it and redistribute it
    11  *  freely, subject to the following restrictions:
    12  * 
    13  *  1. The origin of this software must not be misrepresented; you must not
    14  *     claim that you wrote the original software. If you use this software
    15  *     in a product, an acknowledgment in the product documentation would be
    16  *     appreciated but is not required.
    17  *  2. Altered source versions must be plainly marked as such, and must not be
    18  *     misrepresented as being the original software.
    19  *  3. This notice may not be removed or altered from any source distribution.
    20  */
    21 #include "../SDL_internal.h"
    22 
    23 #if SDL_VIDEO_OPENGL_EGL
    24 
    25 #if SDL_VIDEO_DRIVER_WINDOWS || SDL_VIDEO_DRIVER_WINRT
    26 #include "../core/windows/SDL_windows.h"
    27 #endif
    28 #if SDL_VIDEO_DRIVER_ANDROID
    29 #include <android/native_window.h>
    30 #endif
    31 
    32 #include "SDL_sysvideo.h"
    33 #include "SDL_log.h"
    34 #include "SDL_egl_c.h"
    35 #include "SDL_loadso.h"
    36 #include "SDL_hints.h"
    37 
    38 #ifdef EGL_KHR_create_context
    39 /* EGL_OPENGL_ES3_BIT_KHR was added in version 13 of the extension. */
    40 #ifndef EGL_OPENGL_ES3_BIT_KHR
    41 #define EGL_OPENGL_ES3_BIT_KHR 0x00000040
    42 #endif
    43 #endif /* EGL_KHR_create_context */
    44 
    45 #if SDL_VIDEO_DRIVER_RPI
    46 /* Raspbian places the OpenGL ES/EGL binaries in a non standard path */
    47 #define DEFAULT_EGL "/opt/vc/lib/libbrcmEGL.so"
    48 #define DEFAULT_OGL_ES2 "/opt/vc/lib/libbrcmGLESv2.so"
    49 #define ALT_EGL "/opt/vc/lib/libEGL.so"
    50 #define ALT_OGL_ES2 "/opt/vc/lib/libGLESv2.so"
    51 #define DEFAULT_OGL_ES_PVR "/opt/vc/lib/libGLES_CM.so"
    52 #define DEFAULT_OGL_ES "/opt/vc/lib/libGLESv1_CM.so"
    53 
    54 #elif SDL_VIDEO_DRIVER_ANDROID || SDL_VIDEO_DRIVER_VIVANTE
    55 /* Android */
    56 #define DEFAULT_EGL "libEGL.so"
    57 #define DEFAULT_OGL_ES2 "libGLESv2.so"
    58 #define DEFAULT_OGL_ES_PVR "libGLES_CM.so"
    59 #define DEFAULT_OGL_ES "libGLESv1_CM.so"
    60 
    61 #elif SDL_VIDEO_DRIVER_WINDOWS || SDL_VIDEO_DRIVER_WINRT
    62 /* EGL AND OpenGL ES support via ANGLE */
    63 #define DEFAULT_EGL "libEGL.dll"
    64 #define DEFAULT_OGL_ES2 "libGLESv2.dll"
    65 #define DEFAULT_OGL_ES_PVR "libGLES_CM.dll"
    66 #define DEFAULT_OGL_ES "libGLESv1_CM.dll"
    67 
    68 #else
    69 /* Desktop Linux */
    70 #define DEFAULT_OGL "libGL.so.1"
    71 #define DEFAULT_EGL "libEGL.so.1"
    72 #define DEFAULT_OGL_ES2 "libGLESv2.so.2"
    73 #define DEFAULT_OGL_ES_PVR "libGLES_CM.so.1"
    74 #define DEFAULT_OGL_ES "libGLESv1_CM.so.1"
    75 #endif /* SDL_VIDEO_DRIVER_RPI */
    76 
    77 #ifdef SDL_VIDEO_STATIC_ANGLE
    78 #define LOAD_FUNC(NAME) \
    79 _this->egl_data->NAME = (void *)NAME;
    80 #else
    81 #define LOAD_FUNC(NAME) \
    82 _this->egl_data->NAME = SDL_LoadFunction(_this->egl_data->dll_handle, #NAME); \
    83 if (!_this->egl_data->NAME) \
    84 { \
    85     return SDL_SetError("Could not retrieve EGL function " #NAME); \
    86 }
    87 #endif
    88 
    89 static const char * SDL_EGL_GetErrorName(EGLint eglErrorCode)
    90 {
    91 #define SDL_EGL_ERROR_TRANSLATE(e) case e: return #e;
    92     switch (eglErrorCode) {
    93         SDL_EGL_ERROR_TRANSLATE(EGL_SUCCESS);
    94         SDL_EGL_ERROR_TRANSLATE(EGL_NOT_INITIALIZED);
    95         SDL_EGL_ERROR_TRANSLATE(EGL_BAD_ACCESS);
    96         SDL_EGL_ERROR_TRANSLATE(EGL_BAD_ALLOC);
    97         SDL_EGL_ERROR_TRANSLATE(EGL_BAD_ATTRIBUTE);
    98         SDL_EGL_ERROR_TRANSLATE(EGL_BAD_CONTEXT);
    99         SDL_EGL_ERROR_TRANSLATE(EGL_BAD_CONFIG);
   100         SDL_EGL_ERROR_TRANSLATE(EGL_BAD_CURRENT_SURFACE);
   101         SDL_EGL_ERROR_TRANSLATE(EGL_BAD_DISPLAY);
   102         SDL_EGL_ERROR_TRANSLATE(EGL_BAD_SURFACE);
   103         SDL_EGL_ERROR_TRANSLATE(EGL_BAD_MATCH);
   104         SDL_EGL_ERROR_TRANSLATE(EGL_BAD_PARAMETER);
   105         SDL_EGL_ERROR_TRANSLATE(EGL_BAD_NATIVE_PIXMAP);
   106         SDL_EGL_ERROR_TRANSLATE(EGL_BAD_NATIVE_WINDOW);
   107         SDL_EGL_ERROR_TRANSLATE(EGL_CONTEXT_LOST);
   108     }
   109     return "";
   110 }
   111 
   112 int SDL_EGL_SetErrorEx(const char * message, const char * eglFunctionName, EGLint eglErrorCode)
   113 {
   114     const char * errorText = SDL_EGL_GetErrorName(eglErrorCode);
   115     char altErrorText[32];
   116     if (errorText[0] == '\0') {
   117         /* An unknown-to-SDL error code was reported.  Report its hexadecimal value, instead of its name. */
   118         SDL_snprintf(altErrorText, SDL_arraysize(altErrorText), "0x%x", (unsigned int)eglErrorCode);
   119         errorText = altErrorText;
   120     }
   121     return SDL_SetError("%s (call to %s failed, reporting an error of %s)", message, eglFunctionName, errorText);
   122 }
   123 
   124 /* EGL implementation of SDL OpenGL ES support */
   125 typedef enum {
   126     SDL_EGL_DISPLAY_EXTENSION,
   127     SDL_EGL_CLIENT_EXTENSION
   128 } SDL_EGL_ExtensionType;
   129 
   130 static SDL_bool SDL_EGL_HasExtension(_THIS, SDL_EGL_ExtensionType type, const char *ext)
   131 {
   132     size_t ext_len;
   133     const char *ext_override;
   134     const char *egl_extstr;
   135     const char *ext_start;
   136 
   137     /* Invalid extensions can be rejected early */
   138     if (ext == NULL || *ext == 0 || SDL_strchr(ext, ' ') != NULL) {
   139         /* SDL_LogDebug(SDL_LOG_CATEGORY_VIDEO, "SDL_EGL_HasExtension: Invalid EGL extension"); */
   140         return SDL_FALSE;
   141     }
   142 
   143     /* Extensions can be masked with an environment variable.
   144      * Unlike the OpenGL override, this will use the set bits of an integer
   145      * to disable the extension.
   146      *  Bit   Action
   147      *  0     If set, the display extension is masked and not present to SDL.
   148      *  1     If set, the client extension is masked and not present to SDL.
   149      */
   150     ext_override = SDL_getenv(ext);
   151     if (ext_override != NULL) {
   152         int disable_ext = SDL_atoi(ext_override);
   153         if (disable_ext & 0x01 && type == SDL_EGL_DISPLAY_EXTENSION) {
   154             return SDL_FALSE;
   155         } else if (disable_ext & 0x02 && type == SDL_EGL_CLIENT_EXTENSION) {
   156             return SDL_FALSE;
   157         }
   158     }
   159 
   160     ext_len = SDL_strlen(ext);
   161     switch (type) {
   162     case SDL_EGL_DISPLAY_EXTENSION:
   163         egl_extstr = _this->egl_data->eglQueryString(_this->egl_data->egl_display, EGL_EXTENSIONS);
   164         break;
   165     case SDL_EGL_CLIENT_EXTENSION:
   166         /* EGL_EXT_client_extensions modifies eglQueryString to return client extensions
   167          * if EGL_NO_DISPLAY is passed. Implementations without it are required to return NULL.
   168          * This behavior is included in EGL 1.5.
   169          */
   170         egl_extstr = _this->egl_data->eglQueryString(EGL_NO_DISPLAY, EGL_EXTENSIONS);
   171         break;
   172     default:
   173         /* SDL_LogDebug(SDL_LOG_CATEGORY_VIDEO, "SDL_EGL_HasExtension: Invalid extension type"); */
   174         return SDL_FALSE;
   175     }
   176 
   177     if (egl_extstr != NULL) {
   178         ext_start = egl_extstr;
   179 
   180         while (*ext_start) {
   181             ext_start = SDL_strstr(ext_start, ext);
   182             if (ext_start == NULL) {
   183                 return SDL_FALSE;
   184             }
   185             /* Check if the match is not just a substring of one of the extensions */
   186             if (ext_start == egl_extstr || *(ext_start - 1) == ' ') {
   187                 if (ext_start[ext_len] == ' ' || ext_start[ext_len] == 0) {
   188                     return SDL_TRUE;
   189                 }
   190             }
   191             /* If the search stopped in the middle of an extension, skip to the end of it */
   192             ext_start += ext_len;
   193             while (*ext_start != ' ' && *ext_start != 0) {
   194                 ext_start++;
   195             }
   196         }
   197     }
   198 
   199     return SDL_FALSE;
   200 }
   201 
   202 void *
   203 SDL_EGL_GetProcAddress(_THIS, const char *proc)
   204 {
   205     static char procname[1024];
   206     void *retval;
   207     
   208     /* eglGetProcAddress is busted on Android http://code.google.com/p/android/issues/detail?id=7681 */
   209 #if !defined(SDL_VIDEO_DRIVER_ANDROID) && !defined(SDL_VIDEO_DRIVER_MIR) 
   210     if (_this->egl_data->eglGetProcAddress) {
   211         retval = _this->egl_data->eglGetProcAddress(proc);
   212         if (retval) {
   213             return retval;
   214         }
   215     }
   216 #endif
   217     
   218     retval = SDL_LoadFunction(_this->egl_data->egl_dll_handle, proc);
   219     if (!retval && SDL_strlen(proc) <= 1022) {
   220         procname[0] = '_';
   221         SDL_strlcpy(procname + 1, proc, 1022);
   222         retval = SDL_LoadFunction(_this->egl_data->egl_dll_handle, procname);
   223     }
   224     return retval;
   225 }
   226 
   227 void
   228 SDL_EGL_UnloadLibrary(_THIS)
   229 {
   230     if (_this->egl_data) {
   231         if (_this->egl_data->egl_display) {
   232             _this->egl_data->eglTerminate(_this->egl_data->egl_display);
   233             _this->egl_data->egl_display = NULL;
   234         }
   235 
   236         if (_this->egl_data->dll_handle) {
   237             SDL_UnloadObject(_this->egl_data->dll_handle);
   238             _this->egl_data->dll_handle = NULL;
   239         }
   240         if (_this->egl_data->egl_dll_handle) {
   241             SDL_UnloadObject(_this->egl_data->egl_dll_handle);
   242             _this->egl_data->egl_dll_handle = NULL;
   243         }
   244         
   245         SDL_free(_this->egl_data);
   246         _this->egl_data = NULL;
   247     }
   248 }
   249 
   250 int
   251 SDL_EGL_LoadLibrary(_THIS, const char *egl_path, NativeDisplayType native_display, EGLenum platform)
   252 {
   253     void *dll_handle = NULL, *egl_dll_handle = NULL; /* The naming is counter intuitive, but hey, I just work here -- Gabriel */
   254     const char *path = NULL;
   255     int egl_version_major = 0, egl_version_minor = 0;
   256 #if SDL_VIDEO_DRIVER_WINDOWS || SDL_VIDEO_DRIVER_WINRT
   257     const char *d3dcompiler;
   258 #endif
   259 
   260     if (_this->egl_data) {
   261         return SDL_SetError("OpenGL ES context already created");
   262     }
   263 
   264     _this->egl_data = (struct SDL_EGL_VideoData *) SDL_calloc(1, sizeof(SDL_EGL_VideoData));
   265     if (!_this->egl_data) {
   266         return SDL_OutOfMemory();
   267     }
   268 
   269 #if SDL_VIDEO_DRIVER_WINDOWS || SDL_VIDEO_DRIVER_WINRT
   270     d3dcompiler = SDL_GetHint(SDL_HINT_VIDEO_WIN_D3DCOMPILER);
   271     if (!d3dcompiler) {
   272         if (WIN_IsWindowsVistaOrGreater()) {
   273             d3dcompiler = "d3dcompiler_46.dll";
   274         } else {
   275             d3dcompiler = "d3dcompiler_43.dll";
   276         }
   277     }
   278     if (SDL_strcasecmp(d3dcompiler, "none") != 0) {
   279         if (SDL_LoadObject(d3dcompiler) == NULL) {
   280             SDL_ClearError();
   281         }
   282     }
   283 #endif
   284 
   285 #ifndef SDL_VIDEO_STATIC_ANGLE
   286     /* A funny thing, loading EGL.so first does not work on the Raspberry, so we load libGL* first */
   287     path = SDL_getenv("SDL_VIDEO_GL_DRIVER");
   288     if (path != NULL) {
   289         egl_dll_handle = SDL_LoadObject(path);
   290     }
   291 
   292     if (egl_dll_handle == NULL) {
   293         if (_this->gl_config.profile_mask == SDL_GL_CONTEXT_PROFILE_ES) {
   294             if (_this->gl_config.major_version > 1) {
   295                 path = DEFAULT_OGL_ES2;
   296                 egl_dll_handle = SDL_LoadObject(path);
   297 #ifdef ALT_OGL_ES2
   298                 if (egl_dll_handle == NULL) {
   299                     path = ALT_OGL_ES2;
   300                     egl_dll_handle = SDL_LoadObject(path);
   301                 }
   302 #endif
   303 
   304             } else {
   305                 path = DEFAULT_OGL_ES;
   306                 egl_dll_handle = SDL_LoadObject(path);
   307                 if (egl_dll_handle == NULL) {
   308                     path = DEFAULT_OGL_ES_PVR;
   309                     egl_dll_handle = SDL_LoadObject(path);
   310                 }
   311             }
   312         }
   313 #ifdef DEFAULT_OGL         
   314         else {
   315             path = DEFAULT_OGL;
   316             egl_dll_handle = SDL_LoadObject(path);
   317         }
   318 #endif        
   319     }
   320     _this->egl_data->egl_dll_handle = egl_dll_handle;
   321 
   322     if (egl_dll_handle == NULL) {
   323         return SDL_SetError("Could not initialize OpenGL / GLES library");
   324     }
   325 
   326     /* Loading libGL* in the previous step took care of loading libEGL.so, but we future proof by double checking */
   327     if (egl_path != NULL) {
   328         dll_handle = SDL_LoadObject(egl_path);
   329     }   
   330     /* Try loading a EGL symbol, if it does not work try the default library paths */
   331     if (dll_handle == NULL || SDL_LoadFunction(dll_handle, "eglChooseConfig") == NULL) {
   332         if (dll_handle != NULL) {
   333             SDL_UnloadObject(dll_handle);
   334         }
   335         path = SDL_getenv("SDL_VIDEO_EGL_DRIVER");
   336         if (path == NULL) {
   337             path = DEFAULT_EGL;
   338         }
   339         dll_handle = SDL_LoadObject(path);
   340 
   341 #ifdef ALT_EGL
   342         if (dll_handle == NULL) {
   343             path = ALT_EGL;
   344             dll_handle = SDL_LoadObject(path);
   345         }
   346 #endif
   347 
   348         if (dll_handle == NULL || SDL_LoadFunction(dll_handle, "eglChooseConfig") == NULL) {
   349             if (dll_handle != NULL) {
   350                 SDL_UnloadObject(dll_handle);
   351             }
   352             return SDL_SetError("Could not load EGL library");
   353         }
   354         SDL_ClearError();
   355     }
   356 #endif
   357 
   358     _this->egl_data->dll_handle = dll_handle;
   359 
   360     /* Load new function pointers */
   361     LOAD_FUNC(eglGetDisplay);
   362     LOAD_FUNC(eglInitialize);
   363     LOAD_FUNC(eglTerminate);
   364     LOAD_FUNC(eglGetProcAddress);
   365     LOAD_FUNC(eglChooseConfig);
   366     LOAD_FUNC(eglGetConfigAttrib);
   367     LOAD_FUNC(eglCreateContext);
   368     LOAD_FUNC(eglDestroyContext);
   369     LOAD_FUNC(eglCreateWindowSurface);
   370     LOAD_FUNC(eglDestroySurface);
   371     LOAD_FUNC(eglMakeCurrent);
   372     LOAD_FUNC(eglSwapBuffers);
   373     LOAD_FUNC(eglSwapInterval);
   374     LOAD_FUNC(eglWaitNative);
   375     LOAD_FUNC(eglWaitGL);
   376     LOAD_FUNC(eglBindAPI);
   377     LOAD_FUNC(eglQueryString);
   378     LOAD_FUNC(eglGetError);
   379 
   380     if (_this->egl_data->eglQueryString) {
   381         /* EGL 1.5 allows querying for client version */
   382         const char *egl_version = _this->egl_data->eglQueryString(EGL_NO_DISPLAY, EGL_VERSION);
   383         if (egl_version != NULL) {
   384             if (SDL_sscanf(egl_version, "%d.%d", &egl_version_major, &egl_version_minor) != 2) {
   385                 egl_version_major = 0;
   386                 egl_version_minor = 0;
   387                 SDL_LogWarn(SDL_LOG_CATEGORY_VIDEO, "Could not parse EGL version string: %s", egl_version);
   388             }
   389         }
   390     }
   391 
   392     if (egl_version_major == 1 && egl_version_minor == 5) {
   393         LOAD_FUNC(eglGetPlatformDisplay);
   394     }
   395 
   396     _this->egl_data->egl_display = EGL_NO_DISPLAY;
   397 #if !defined(__WINRT__)
   398     if (platform) {
   399         if (egl_version_major == 1 && egl_version_minor == 5) {
   400             _this->egl_data->egl_display = _this->egl_data->eglGetPlatformDisplay(platform, (void *)(size_t)native_display, NULL);
   401         } else {
   402             if (SDL_EGL_HasExtension(_this, SDL_EGL_CLIENT_EXTENSION, "EGL_EXT_platform_base")) {
   403                 _this->egl_data->eglGetPlatformDisplayEXT = SDL_EGL_GetProcAddress(_this, "eglGetPlatformDisplayEXT");
   404                 if (_this->egl_data->eglGetPlatformDisplayEXT) {
   405                     _this->egl_data->egl_display = _this->egl_data->eglGetPlatformDisplayEXT(platform, (void *)(size_t)native_display, NULL);
   406                 }
   407             }
   408         }
   409     }
   410     /* Try the implementation-specific eglGetDisplay even if eglGetPlatformDisplay fails */
   411     if (_this->egl_data->egl_display == EGL_NO_DISPLAY) {
   412         _this->egl_data->egl_display = _this->egl_data->eglGetDisplay(native_display);
   413     }
   414     if (_this->egl_data->egl_display == EGL_NO_DISPLAY) {
   415         return SDL_SetError("Could not get EGL display");
   416     }
   417     
   418     if (_this->egl_data->eglInitialize(_this->egl_data->egl_display, NULL, NULL) != EGL_TRUE) {
   419         return SDL_SetError("Could not initialize EGL");
   420     }
   421 #endif
   422 
   423     if (path) {
   424         SDL_strlcpy(_this->gl_config.driver_path, path, sizeof(_this->gl_config.driver_path) - 1);
   425     } else {
   426         *_this->gl_config.driver_path = '\0';
   427     }
   428     
   429     return 0;
   430 }
   431 
   432 int
   433 SDL_EGL_ChooseConfig(_THIS) 
   434 {
   435 /* 64 seems nice. */
   436     EGLint attribs[64];
   437     EGLint found_configs = 0, value;
   438 #ifdef SDL_VIDEO_DRIVER_KMSDRM
   439     /* Intel EGL on KMS/DRM (al least) returns invalid configs that confuse the bitdiff search used */
   440     /* later in this function, so we simply use the first one when using the KMSDRM driver for now. */
   441     EGLConfig configs[1];
   442 #else
   443     /* 128 seems even nicer here */
   444     EGLConfig configs[128];
   445 #endif
   446     int i, j, best_bitdiff = -1, bitdiff;
   447    
   448     if (!_this->egl_data) {
   449         /* The EGL library wasn't loaded, SDL_GetError() should have info */
   450         return -1;
   451     }
   452   
   453     /* Get a valid EGL configuration */
   454     i = 0;
   455     attribs[i++] = EGL_RED_SIZE;
   456     attribs[i++] = _this->gl_config.red_size;
   457     attribs[i++] = EGL_GREEN_SIZE;
   458     attribs[i++] = _this->gl_config.green_size;
   459     attribs[i++] = EGL_BLUE_SIZE;
   460     attribs[i++] = _this->gl_config.blue_size;
   461     
   462     if (_this->gl_config.alpha_size) {
   463         attribs[i++] = EGL_ALPHA_SIZE;
   464         attribs[i++] = _this->gl_config.alpha_size;
   465     }
   466     
   467     if (_this->gl_config.buffer_size) {
   468         attribs[i++] = EGL_BUFFER_SIZE;
   469         attribs[i++] = _this->gl_config.buffer_size;
   470     }
   471     
   472     attribs[i++] = EGL_DEPTH_SIZE;
   473     attribs[i++] = _this->gl_config.depth_size;
   474     
   475     if (_this->gl_config.stencil_size) {
   476         attribs[i++] = EGL_STENCIL_SIZE;
   477         attribs[i++] = _this->gl_config.stencil_size;
   478     }
   479     
   480     if (_this->gl_config.multisamplebuffers) {
   481         attribs[i++] = EGL_SAMPLE_BUFFERS;
   482         attribs[i++] = _this->gl_config.multisamplebuffers;
   483     }
   484     
   485     if (_this->gl_config.multisamplesamples) {
   486         attribs[i++] = EGL_SAMPLES;
   487         attribs[i++] = _this->gl_config.multisamplesamples;
   488     }
   489 
   490     if (_this->gl_config.framebuffer_srgb_capable) {
   491 #ifdef EGL_KHR_gl_colorspace
   492         if (SDL_EGL_HasExtension(_this, SDL_EGL_DISPLAY_EXTENSION, "EGL_KHR_gl_colorspace")) {
   493             attribs[i++] = EGL_GL_COLORSPACE_KHR;
   494             attribs[i++] = EGL_GL_COLORSPACE_SRGB_KHR;
   495         } else
   496 #endif
   497         {
   498             return SDL_SetError("EGL implementation does not support sRGB system framebuffers");
   499         }
   500     }
   501 
   502     attribs[i++] = EGL_RENDERABLE_TYPE;
   503     if (_this->gl_config.profile_mask == SDL_GL_CONTEXT_PROFILE_ES) {
   504 #ifdef EGL_KHR_create_context
   505         if (_this->gl_config.major_version >= 3 &&
   506             SDL_EGL_HasExtension(_this, SDL_EGL_DISPLAY_EXTENSION, "EGL_KHR_create_context")) {
   507             attribs[i++] = EGL_OPENGL_ES3_BIT_KHR;
   508         } else
   509 #endif
   510         if (_this->gl_config.major_version >= 2) {
   511             attribs[i++] = EGL_OPENGL_ES2_BIT;
   512         } else {
   513             attribs[i++] = EGL_OPENGL_ES_BIT;
   514         }
   515         _this->egl_data->eglBindAPI(EGL_OPENGL_ES_API);
   516     } else {
   517         attribs[i++] = EGL_OPENGL_BIT;
   518         _this->egl_data->eglBindAPI(EGL_OPENGL_API);
   519     }
   520 
   521     attribs[i++] = EGL_NONE;
   522 
   523     if (_this->egl_data->eglChooseConfig(_this->egl_data->egl_display,
   524         attribs,
   525         configs, SDL_arraysize(configs),
   526         &found_configs) == EGL_FALSE ||
   527         found_configs == 0) {
   528         return SDL_EGL_SetError("Couldn't find matching EGL config", "eglChooseConfig");
   529     }
   530 
   531     /* eglChooseConfig returns a number of configurations that match or exceed the requested attribs. */
   532     /* From those, we select the one that matches our requirements more closely via a makeshift algorithm */
   533 
   534     for (i = 0; i < found_configs; i++ ) {
   535         bitdiff = 0;
   536         for (j = 0; j < SDL_arraysize(attribs) - 1; j += 2) {
   537             if (attribs[j] == EGL_NONE) {
   538                break;
   539             }
   540             
   541             if ( attribs[j+1] != EGL_DONT_CARE && (
   542                 attribs[j] == EGL_RED_SIZE ||
   543                 attribs[j] == EGL_GREEN_SIZE ||
   544                 attribs[j] == EGL_BLUE_SIZE ||
   545                 attribs[j] == EGL_ALPHA_SIZE ||
   546                 attribs[j] == EGL_DEPTH_SIZE ||
   547                 attribs[j] == EGL_STENCIL_SIZE)) {
   548                 _this->egl_data->eglGetConfigAttrib(_this->egl_data->egl_display, configs[i], attribs[j], &value);
   549                 bitdiff += value - attribs[j + 1]; /* value is always >= attrib */
   550             }
   551         }
   552 
   553         if (bitdiff < best_bitdiff || best_bitdiff == -1) {
   554             _this->egl_data->egl_config = configs[i];
   555             
   556             best_bitdiff = bitdiff;
   557         }
   558 
   559         if (bitdiff == 0) {
   560             break; /* we found an exact match! */
   561         }
   562     }
   563     
   564     return 0;
   565 }
   566 
   567 SDL_GLContext
   568 SDL_EGL_CreateContext(_THIS, EGLSurface egl_surface)
   569 {
   570     /* max 14 values plus terminator. */
   571     EGLint attribs[15];
   572     int attr = 0;
   573 
   574     EGLContext egl_context, share_context = EGL_NO_CONTEXT;
   575     EGLint profile_mask = _this->gl_config.profile_mask;
   576     EGLint major_version = _this->gl_config.major_version;
   577     EGLint minor_version = _this->gl_config.minor_version;
   578     SDL_bool profile_es = (profile_mask == SDL_GL_CONTEXT_PROFILE_ES);
   579 
   580     if (!_this->egl_data) {
   581         /* The EGL library wasn't loaded, SDL_GetError() should have info */
   582         return NULL;
   583     }
   584 
   585     if (_this->gl_config.share_with_current_context) {
   586         share_context = (EGLContext)SDL_GL_GetCurrentContext();
   587     }
   588 
   589     /* Set the context version and other attributes. */
   590     if ((major_version < 3 || (minor_version == 0 && profile_es)) &&
   591         _this->gl_config.flags == 0 &&
   592         (profile_mask == 0 || profile_es)) {
   593         /* Create a context without using EGL_KHR_create_context attribs.
   594          * When creating a GLES context without EGL_KHR_create_context we can
   595          * only specify the major version. When creating a desktop GL context
   596          * we can't specify any version, so we only try in that case when the
   597          * version is less than 3.0 (matches SDL's GLX/WGL behavior.)
   598          */
   599         if (profile_es) {
   600             attribs[attr++] = EGL_CONTEXT_CLIENT_VERSION;
   601             attribs[attr++] = SDL_max(major_version, 1);
   602         }
   603     } else {
   604 #ifdef EGL_KHR_create_context
   605         /* The Major/minor version, context profiles, and context flags can
   606          * only be specified when this extension is available.
   607          */
   608         if (SDL_EGL_HasExtension(_this, SDL_EGL_DISPLAY_EXTENSION, "EGL_KHR_create_context")) {
   609             attribs[attr++] = EGL_CONTEXT_MAJOR_VERSION_KHR;
   610             attribs[attr++] = major_version;
   611             attribs[attr++] = EGL_CONTEXT_MINOR_VERSION_KHR;
   612             attribs[attr++] = minor_version;
   613 
   614             /* SDL profile bits match EGL profile bits. */
   615             if (profile_mask != 0 && profile_mask != SDL_GL_CONTEXT_PROFILE_ES) {
   616                 attribs[attr++] = EGL_CONTEXT_OPENGL_PROFILE_MASK_KHR;
   617                 attribs[attr++] = profile_mask;
   618             }
   619 
   620             /* SDL flags match EGL flags. */
   621             if (_this->gl_config.flags != 0) {
   622                 attribs[attr++] = EGL_CONTEXT_FLAGS_KHR;
   623                 attribs[attr++] = _this->gl_config.flags;
   624             }
   625         } else
   626 #endif /* EGL_KHR_create_context */
   627         {
   628             SDL_SetError("Could not create EGL context (context attributes are not supported)");
   629             return NULL;
   630         }
   631     }
   632 
   633     if (_this->gl_config.no_error) {
   634 #ifdef EGL_KHR_create_context_no_error
   635         if (SDL_EGL_HasExtension(_this, SDL_EGL_DISPLAY_EXTENSION, "EGL_KHR_create_context_no_error")) {
   636             attribs[attr++] = EGL_CONTEXT_OPENGL_NO_ERROR_KHR;
   637             attribs[attr++] = _this->gl_config.no_error;
   638         } else
   639 #endif
   640         {
   641             SDL_SetError("EGL implementation does not support no_error contexts");
   642             return NULL;
   643         }
   644     }
   645 
   646     attribs[attr++] = EGL_NONE;
   647 
   648     /* Bind the API */
   649     if (profile_es) {
   650         _this->egl_data->eglBindAPI(EGL_OPENGL_ES_API);
   651     } else {
   652         _this->egl_data->eglBindAPI(EGL_OPENGL_API);
   653     }
   654 
   655     egl_context = _this->egl_data->eglCreateContext(_this->egl_data->egl_display,
   656                                       _this->egl_data->egl_config,
   657                                       share_context, attribs);
   658 
   659     if (egl_context == EGL_NO_CONTEXT) {
   660         SDL_EGL_SetError("Could not create EGL context", "eglCreateContext");
   661         return NULL;
   662     }
   663 
   664     _this->egl_data->egl_swapinterval = 0;
   665 
   666     if (SDL_EGL_MakeCurrent(_this, egl_surface, egl_context) < 0) {
   667         /* Save the SDL error set by SDL_EGL_MakeCurrent */
   668         char errorText[1024];
   669         SDL_strlcpy(errorText, SDL_GetError(), SDL_arraysize(errorText));
   670 
   671         /* Delete the context, which may alter the value returned by SDL_GetError() */
   672         SDL_EGL_DeleteContext(_this, egl_context);
   673 
   674         /* Restore the SDL error */
   675         SDL_SetError("%s", errorText);
   676 
   677         return NULL;
   678     }
   679 
   680     return (SDL_GLContext) egl_context;
   681 }
   682 
   683 int
   684 SDL_EGL_MakeCurrent(_THIS, EGLSurface egl_surface, SDL_GLContext context)
   685 {
   686     EGLContext egl_context = (EGLContext) context;
   687 
   688     if (!_this->egl_data) {
   689         return SDL_SetError("OpenGL not initialized");
   690     }
   691     
   692     /* The android emulator crashes badly if you try to eglMakeCurrent 
   693      * with a valid context and invalid surface, so we have to check for both here.
   694      */
   695     if (!egl_context || !egl_surface) {
   696          _this->egl_data->eglMakeCurrent(_this->egl_data->egl_display, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
   697     } else {
   698         if (!_this->egl_data->eglMakeCurrent(_this->egl_data->egl_display,
   699             egl_surface, egl_surface, egl_context)) {
   700             return SDL_EGL_SetError("Unable to make EGL context current", "eglMakeCurrent");
   701         }
   702     }
   703       
   704     return 0;
   705 }
   706 
   707 int
   708 SDL_EGL_SetSwapInterval(_THIS, int interval)
   709 {
   710     EGLBoolean status;
   711     
   712     if (!_this->egl_data) {
   713         return SDL_SetError("EGL not initialized");
   714     }
   715     
   716     status = _this->egl_data->eglSwapInterval(_this->egl_data->egl_display, interval);
   717     if (status == EGL_TRUE) {
   718         _this->egl_data->egl_swapinterval = interval;
   719         return 0;
   720     }
   721     
   722     return SDL_EGL_SetError("Unable to set the EGL swap interval", "eglSwapInterval");
   723 }
   724 
   725 int
   726 SDL_EGL_GetSwapInterval(_THIS)
   727 {
   728     if (!_this->egl_data) {
   729         SDL_SetError("EGL not initialized");
   730         return 0;
   731     }
   732     
   733     return _this->egl_data->egl_swapinterval;
   734 }
   735 
   736 int
   737 SDL_EGL_SwapBuffers(_THIS, EGLSurface egl_surface)
   738 {
   739     if (!_this->egl_data->eglSwapBuffers(_this->egl_data->egl_display, egl_surface)) {
   740         return SDL_EGL_SetError("unable to show color buffer in an OS-native window", "eglSwapBuffers");
   741     }
   742     return 0;
   743 }
   744 
   745 void
   746 SDL_EGL_DeleteContext(_THIS, SDL_GLContext context)
   747 {
   748     EGLContext egl_context = (EGLContext) context;
   749 
   750     /* Clean up GLES and EGL */
   751     if (!_this->egl_data) {
   752         return;
   753     }
   754     
   755     if (egl_context != NULL && egl_context != EGL_NO_CONTEXT) {
   756         SDL_EGL_MakeCurrent(_this, NULL, NULL);
   757         _this->egl_data->eglDestroyContext(_this->egl_data->egl_display, egl_context);
   758     }
   759         
   760 }
   761 
   762 EGLSurface *
   763 SDL_EGL_CreateSurface(_THIS, NativeWindowType nw) 
   764 {
   765     EGLSurface * surface;
   766 
   767     if (SDL_EGL_ChooseConfig(_this) != 0) {
   768         return EGL_NO_SURFACE;
   769     }
   770     
   771 #if SDL_VIDEO_DRIVER_ANDROID
   772     {
   773         /* Android docs recommend doing this!
   774          * Ref: http://developer.android.com/reference/android/app/NativeActivity.html 
   775          */
   776         EGLint format;
   777         _this->egl_data->eglGetConfigAttrib(_this->egl_data->egl_display,
   778                                             _this->egl_data->egl_config, 
   779                                             EGL_NATIVE_VISUAL_ID, &format);
   780 
   781         ANativeWindow_setBuffersGeometry(nw, 0, 0, format);
   782     }
   783 #endif    
   784     
   785     surface = _this->egl_data->eglCreateWindowSurface(
   786             _this->egl_data->egl_display,
   787             _this->egl_data->egl_config,
   788             nw, NULL);
   789     if (surface == EGL_NO_SURFACE) {
   790         SDL_EGL_SetError("unable to create an EGL window surface", "eglCreateWindowSurface");
   791     }
   792     return surface;
   793 }
   794 
   795 void
   796 SDL_EGL_DestroySurface(_THIS, EGLSurface egl_surface) 
   797 {
   798     if (!_this->egl_data) {
   799         return;
   800     }
   801     
   802     if (egl_surface != EGL_NO_SURFACE) {
   803         _this->egl_data->eglDestroySurface(_this->egl_data->egl_display, egl_surface);
   804     }
   805 }
   806 
   807 #endif /* SDL_VIDEO_OPENGL_EGL */
   808 
   809 /* vi: set ts=4 sw=4 expandtab: */
   810