Exemple #1
0
EGLSurface *
SDL_EGL_CreateSurface(_THIS, NativeWindowType nw) 
{
    /* max 2 values plus terminator. */
    EGLint attribs[3];
    int attr = 0;

    EGLSurface * surface;

    if (SDL_EGL_ChooseConfig(_this) != 0) {
        return EGL_NO_SURFACE;
    }
    
#if SDL_VIDEO_DRIVER_ANDROID
    {
        /* Android docs recommend doing this!
         * Ref: http://developer.android.com/reference/android/app/NativeActivity.html 
         */
        EGLint format;
        _this->egl_data->eglGetConfigAttrib(_this->egl_data->egl_display,
                                            _this->egl_data->egl_config, 
                                            EGL_NATIVE_VISUAL_ID, &format);

        ANativeWindow_setBuffersGeometry(nw, 0, 0, format);

        /* Update SurfaceView holder format.
         * May triggers a sequence surfaceDestroyed(), surfaceCreated(), surfaceChanged(). */
        Android_JNI_SetSurfaceViewFormat(format);
    }
#endif    
    if (_this->gl_config.framebuffer_srgb_capable) {
#ifdef EGL_KHR_gl_colorspace
        if (SDL_EGL_HasExtension(_this, SDL_EGL_DISPLAY_EXTENSION, "EGL_KHR_gl_colorspace")) {
            attribs[attr++] = EGL_GL_COLORSPACE_KHR;
            attribs[attr++] = EGL_GL_COLORSPACE_SRGB_KHR;
        } else
#endif
        {
            SDL_SetError("EGL implementation does not support sRGB system framebuffers");
            return EGL_NO_SURFACE;
        }
    }

    attribs[attr++] = EGL_NONE;
    
    surface = _this->egl_data->eglCreateWindowSurface(
            _this->egl_data->egl_display,
            _this->egl_data->egl_config,
            nw, &attribs[0]);
    if (surface == EGL_NO_SURFACE) {
        SDL_EGL_SetError("unable to create an EGL window surface", "eglCreateWindowSurface");
    }
    return surface;
}
Exemple #2
0
SDL_GLContext
SDL_EGL_CreateContext(_THIS, EGLSurface egl_surface)
{
    /* max 14 values plus terminator. */
    EGLint attribs[15];
    int attr = 0;

    EGLContext egl_context, share_context = EGL_NO_CONTEXT;
    EGLint profile_mask = _this->gl_config.profile_mask;
    EGLint major_version = _this->gl_config.major_version;
    EGLint minor_version = _this->gl_config.minor_version;
    SDL_bool profile_es = (profile_mask == SDL_GL_CONTEXT_PROFILE_ES);

    if (!_this->egl_data) {
        /* The EGL library wasn't loaded, SDL_GetError() should have info */
        return NULL;
    }

    if (_this->gl_config.share_with_current_context) {
        share_context = (EGLContext)SDL_GL_GetCurrentContext();
    }

    /* Set the context version and other attributes. */
    if ((major_version < 3 || (minor_version == 0 && profile_es)) &&
            _this->gl_config.flags == 0 &&
            (profile_mask == 0 || profile_es)) {
        /* Create a context without using EGL_KHR_create_context attribs.
         * When creating a GLES context without EGL_KHR_create_context we can
         * only specify the major version. When creating a desktop GL context
         * we can't specify any version, so we only try in that case when the
         * version is less than 3.0 (matches SDL's GLX/WGL behavior.)
         */
        if (profile_es) {
            attribs[attr++] = EGL_CONTEXT_CLIENT_VERSION;
            attribs[attr++] = SDL_max(major_version, 1);
        }
    } else {
#ifdef EGL_KHR_create_context
        /* The Major/minor version, context profiles, and context flags can
         * only be specified when this extension is available.
         */
        if (SDL_EGL_HasExtension(_this, "EGL_KHR_create_context")) {
            attribs[attr++] = EGL_CONTEXT_MAJOR_VERSION_KHR;
            attribs[attr++] = major_version;
            attribs[attr++] = EGL_CONTEXT_MINOR_VERSION_KHR;
            attribs[attr++] = minor_version;

            /* SDL profile bits match EGL profile bits. */
            if (profile_mask != 0 && profile_mask != SDL_GL_CONTEXT_PROFILE_ES) {
                attribs[attr++] = EGL_CONTEXT_OPENGL_PROFILE_MASK_KHR;
                attribs[attr++] = profile_mask;
            }

            /* SDL flags match EGL flags. */
            if (_this->gl_config.flags != 0) {
                attribs[attr++] = EGL_CONTEXT_FLAGS_KHR;
                attribs[attr++] = _this->gl_config.flags;
            }
        } else
#endif /* EGL_KHR_create_context */
        {
            SDL_SetError("Could not create EGL context (context attributes are not supported)");
            return NULL;
        }
    }

    attribs[attr++] = EGL_NONE;

    /* Bind the API */
    if (profile_es) {
        _this->egl_data->eglBindAPI(EGL_OPENGL_ES_API);
    } else {
        _this->egl_data->eglBindAPI(EGL_OPENGL_API);
    }

    egl_context = _this->egl_data->eglCreateContext(_this->egl_data->egl_display,
                  _this->egl_data->egl_config,
                  share_context, attribs);

    if (egl_context == EGL_NO_CONTEXT) {
        SDL_SetError("Could not create EGL context");
        return NULL;
    }

    _this->egl_data->egl_swapinterval = 0;

    if (SDL_EGL_MakeCurrent(_this, egl_surface, egl_context) < 0) {
        SDL_EGL_DeleteContext(_this, egl_context);
        SDL_SetError("Could not make EGL context current");
        return NULL;
    }

    return (SDL_GLContext) egl_context;
}
Exemple #3
0
int
SDL_EGL_ChooseConfig(_THIS)
{
    /* 64 seems nice. */
    EGLint attribs[64];
    EGLint found_configs = 0, value;
    /* 128 seems even nicer here */
    EGLConfig configs[128];
    int i, j, best_bitdiff = -1, bitdiff;

    if (!_this->egl_data) {
        /* The EGL library wasn't loaded, SDL_GetError() should have info */
        return -1;
    }

    /* Get a valid EGL configuration */
    i = 0;
    attribs[i++] = EGL_RED_SIZE;
    attribs[i++] = _this->gl_config.red_size;
    attribs[i++] = EGL_GREEN_SIZE;
    attribs[i++] = _this->gl_config.green_size;
    attribs[i++] = EGL_BLUE_SIZE;
    attribs[i++] = _this->gl_config.blue_size;

    if (_this->gl_config.alpha_size) {
        attribs[i++] = EGL_ALPHA_SIZE;
        attribs[i++] = _this->gl_config.alpha_size;
    }

    if (_this->gl_config.buffer_size) {
        attribs[i++] = EGL_BUFFER_SIZE;
        attribs[i++] = _this->gl_config.buffer_size;
    }

    attribs[i++] = EGL_DEPTH_SIZE;
    attribs[i++] = _this->gl_config.depth_size;

    if (_this->gl_config.stencil_size) {
        attribs[i++] = EGL_STENCIL_SIZE;
        attribs[i++] = _this->gl_config.stencil_size;
    }

    if (_this->gl_config.multisamplebuffers) {
        attribs[i++] = EGL_SAMPLE_BUFFERS;
        attribs[i++] = _this->gl_config.multisamplebuffers;
    }

    if (_this->gl_config.multisamplesamples) {
        attribs[i++] = EGL_SAMPLES;
        attribs[i++] = _this->gl_config.multisamplesamples;
    }

    attribs[i++] = EGL_RENDERABLE_TYPE;
    if (_this->gl_config.profile_mask == SDL_GL_CONTEXT_PROFILE_ES) {
#ifdef EGL_KHR_create_context
        if (_this->gl_config.major_version >= 3 &&
                SDL_EGL_HasExtension(_this, "EGL_KHR_create_context")) {
            attribs[i++] = EGL_OPENGL_ES3_BIT_KHR;
        } else
#endif
            if (_this->gl_config.major_version >= 2) {
                attribs[i++] = EGL_OPENGL_ES2_BIT;
            } else {
                attribs[i++] = EGL_OPENGL_ES_BIT;
            }
        _this->egl_data->eglBindAPI(EGL_OPENGL_ES_API);
    } else {
        attribs[i++] = EGL_OPENGL_BIT;
        _this->egl_data->eglBindAPI(EGL_OPENGL_API);
    }

    attribs[i++] = EGL_NONE;

    if (_this->egl_data->eglChooseConfig(_this->egl_data->egl_display,
                                         attribs,
                                         configs, SDL_arraysize(configs),
                                         &found_configs) == EGL_FALSE ||
            found_configs == 0) {
        return SDL_SetError("Couldn't find matching EGL config");
    }

    /* eglChooseConfig returns a number of configurations that match or exceed the requested attribs. */
    /* From those, we select the one that matches our requirements more closely via a makeshift algorithm */

    for (i = 0; i < found_configs; i++ ) {
        bitdiff = 0;
        for (j = 0; j < SDL_arraysize(attribs) - 1; j += 2) {
            if (attribs[j] == EGL_NONE) {
                break;
            }

            if ( attribs[j+1] != EGL_DONT_CARE && (
                        attribs[j] == EGL_RED_SIZE ||
                        attribs[j] == EGL_GREEN_SIZE ||
                        attribs[j] == EGL_BLUE_SIZE ||
                        attribs[j] == EGL_ALPHA_SIZE ||
                        attribs[j] == EGL_DEPTH_SIZE ||
                        attribs[j] == EGL_STENCIL_SIZE)) {
                _this->egl_data->eglGetConfigAttrib(_this->egl_data->egl_display, configs[i], attribs[j], &value);
                bitdiff += value - attribs[j + 1]; /* value is always >= attrib */
            }
        }

        if (bitdiff < best_bitdiff || best_bitdiff == -1) {
            _this->egl_data->egl_config = configs[i];

            best_bitdiff = bitdiff;
        }

        if (bitdiff == 0) {
            break; /* we found an exact match! */
        }
    }

    return 0;
}
Exemple #4
0
int
SDL_EGL_ChooseConfig(_THIS) 
{
/* 64 seems nice. */
    EGLint attribs[64];
    EGLint found_configs = 0, value;
#ifdef SDL_VIDEO_DRIVER_KMSDRM
    /* Intel EGL on KMS/DRM (al least) returns invalid configs that confuse the bitdiff search used */
    /* later in this function, so we simply use the first one when using the KMSDRM driver for now. */
    EGLConfig configs[1];
#else
    /* 128 seems even nicer here */
    EGLConfig configs[128];
#endif
    int i, j, best_bitdiff = -1, bitdiff;
   
    if (!_this->egl_data) {
        /* The EGL library wasn't loaded, SDL_GetError() should have info */
        return -1;
    }
  
    /* Get a valid EGL configuration */
    i = 0;
    attribs[i++] = EGL_RED_SIZE;
    attribs[i++] = _this->gl_config.red_size;
    attribs[i++] = EGL_GREEN_SIZE;
    attribs[i++] = _this->gl_config.green_size;
    attribs[i++] = EGL_BLUE_SIZE;
    attribs[i++] = _this->gl_config.blue_size;
    
    if (_this->gl_config.alpha_size) {
        attribs[i++] = EGL_ALPHA_SIZE;
        attribs[i++] = _this->gl_config.alpha_size;
    }
    
    if (_this->gl_config.buffer_size) {
        attribs[i++] = EGL_BUFFER_SIZE;
        attribs[i++] = _this->gl_config.buffer_size;
    }
    
    attribs[i++] = EGL_DEPTH_SIZE;
    attribs[i++] = _this->gl_config.depth_size;
    
    if (_this->gl_config.stencil_size) {
        attribs[i++] = EGL_STENCIL_SIZE;
        attribs[i++] = _this->gl_config.stencil_size;
    }
    
    if (_this->gl_config.multisamplebuffers) {
        attribs[i++] = EGL_SAMPLE_BUFFERS;
        attribs[i++] = _this->gl_config.multisamplebuffers;
    }
    
    if (_this->gl_config.multisamplesamples) {
        attribs[i++] = EGL_SAMPLES;
        attribs[i++] = _this->gl_config.multisamplesamples;
    }

    if (_this->gl_config.framebuffer_srgb_capable) {
#ifdef EGL_KHR_gl_colorspace
        if (SDL_EGL_HasExtension(_this, SDL_EGL_DISPLAY_EXTENSION, "EGL_KHR_gl_colorspace")) {
            attribs[i++] = EGL_GL_COLORSPACE_KHR;
            attribs[i++] = EGL_GL_COLORSPACE_SRGB_KHR;
        } else
#endif
        {
            return SDL_SetError("EGL implementation does not support sRGB system framebuffers");
        }
    }

    attribs[i++] = EGL_RENDERABLE_TYPE;
    if (_this->gl_config.profile_mask == SDL_GL_CONTEXT_PROFILE_ES) {
#ifdef EGL_KHR_create_context
        if (_this->gl_config.major_version >= 3 &&
            SDL_EGL_HasExtension(_this, SDL_EGL_DISPLAY_EXTENSION, "EGL_KHR_create_context")) {
            attribs[i++] = EGL_OPENGL_ES3_BIT_KHR;
        } else
#endif
        if (_this->gl_config.major_version >= 2) {
            attribs[i++] = EGL_OPENGL_ES2_BIT;
        } else {
            attribs[i++] = EGL_OPENGL_ES_BIT;
        }
        _this->egl_data->eglBindAPI(EGL_OPENGL_ES_API);
    } else {
        attribs[i++] = EGL_OPENGL_BIT;
        _this->egl_data->eglBindAPI(EGL_OPENGL_API);
    }

    attribs[i++] = EGL_NONE;

    if (_this->egl_data->eglChooseConfig(_this->egl_data->egl_display,
        attribs,
        configs, SDL_arraysize(configs),
        &found_configs) == EGL_FALSE ||
        found_configs == 0) {
        return SDL_EGL_SetError("Couldn't find matching EGL config", "eglChooseConfig");
    }

    /* eglChooseConfig returns a number of configurations that match or exceed the requested attribs. */
    /* From those, we select the one that matches our requirements more closely via a makeshift algorithm */

    for (i = 0; i < found_configs; i++ ) {
        bitdiff = 0;
        for (j = 0; j < SDL_arraysize(attribs) - 1; j += 2) {
            if (attribs[j] == EGL_NONE) {
               break;
            }
            
            if ( attribs[j+1] != EGL_DONT_CARE && (
                attribs[j] == EGL_RED_SIZE ||
                attribs[j] == EGL_GREEN_SIZE ||
                attribs[j] == EGL_BLUE_SIZE ||
                attribs[j] == EGL_ALPHA_SIZE ||
                attribs[j] == EGL_DEPTH_SIZE ||
                attribs[j] == EGL_STENCIL_SIZE)) {
                _this->egl_data->eglGetConfigAttrib(_this->egl_data->egl_display, configs[i], attribs[j], &value);
                bitdiff += value - attribs[j + 1]; /* value is always >= attrib */
            }
        }

        if (bitdiff < best_bitdiff || best_bitdiff == -1) {
            _this->egl_data->egl_config = configs[i];
            
            best_bitdiff = bitdiff;
        }

        if (bitdiff == 0) {
            break; /* we found an exact match! */
        }
    }
    
    return 0;
}
Exemple #5
0
int
SDL_EGL_LoadLibrary(_THIS, const char *egl_path, NativeDisplayType native_display, EGLenum platform)
{
    void *dll_handle = NULL, *egl_dll_handle = NULL; /* The naming is counter intuitive, but hey, I just work here -- Gabriel */
    const char *path = NULL;
    int egl_version_major = 0, egl_version_minor = 0;
#if SDL_VIDEO_DRIVER_WINDOWS || SDL_VIDEO_DRIVER_WINRT
    const char *d3dcompiler;
#endif

    if (_this->egl_data) {
        return SDL_SetError("OpenGL ES context already created");
    }

    _this->egl_data = (struct SDL_EGL_VideoData *) SDL_calloc(1, sizeof(SDL_EGL_VideoData));
    if (!_this->egl_data) {
        return SDL_OutOfMemory();
    }

#if SDL_VIDEO_DRIVER_WINDOWS || SDL_VIDEO_DRIVER_WINRT
    d3dcompiler = SDL_GetHint(SDL_HINT_VIDEO_WIN_D3DCOMPILER);
    if (!d3dcompiler) {
        if (WIN_IsWindowsVistaOrGreater()) {
            d3dcompiler = "d3dcompiler_46.dll";
        } else {
            d3dcompiler = "d3dcompiler_43.dll";
        }
    }
    if (SDL_strcasecmp(d3dcompiler, "none") != 0) {
        if (SDL_LoadObject(d3dcompiler) == NULL) {
            SDL_ClearError();
        }
    }
#endif

#ifndef SDL_VIDEO_STATIC_ANGLE
    /* A funny thing, loading EGL.so first does not work on the Raspberry, so we load libGL* first */
    path = SDL_getenv("SDL_VIDEO_GL_DRIVER");
    if (path != NULL) {
        egl_dll_handle = SDL_LoadObject(path);
    }

    if (egl_dll_handle == NULL) {
        if (_this->gl_config.profile_mask == SDL_GL_CONTEXT_PROFILE_ES) {
            if (_this->gl_config.major_version > 1) {
                path = DEFAULT_OGL_ES2;
                egl_dll_handle = SDL_LoadObject(path);
#ifdef ALT_OGL_ES2
                if (egl_dll_handle == NULL) {
                    path = ALT_OGL_ES2;
                    egl_dll_handle = SDL_LoadObject(path);
                }
#endif

            } else {
                path = DEFAULT_OGL_ES;
                egl_dll_handle = SDL_LoadObject(path);
                if (egl_dll_handle == NULL) {
                    path = DEFAULT_OGL_ES_PVR;
                    egl_dll_handle = SDL_LoadObject(path);
                }
            }
        }
#ifdef DEFAULT_OGL         
        else {
            path = DEFAULT_OGL;
            egl_dll_handle = SDL_LoadObject(path);
        }
#endif        
    }
    _this->egl_data->egl_dll_handle = egl_dll_handle;

    if (egl_dll_handle == NULL) {
        return SDL_SetError("Could not initialize OpenGL / GLES library");
    }

    /* Loading libGL* in the previous step took care of loading libEGL.so, but we future proof by double checking */
    if (egl_path != NULL) {
        dll_handle = SDL_LoadObject(egl_path);
    }   
    /* Try loading a EGL symbol, if it does not work try the default library paths */
    if (dll_handle == NULL || SDL_LoadFunction(dll_handle, "eglChooseConfig") == NULL) {
        if (dll_handle != NULL) {
            SDL_UnloadObject(dll_handle);
        }
        path = SDL_getenv("SDL_VIDEO_EGL_DRIVER");
        if (path == NULL) {
            path = DEFAULT_EGL;
        }
        dll_handle = SDL_LoadObject(path);

#ifdef ALT_EGL
        if (dll_handle == NULL) {
            path = ALT_EGL;
            dll_handle = SDL_LoadObject(path);
        }
#endif

        if (dll_handle == NULL || SDL_LoadFunction(dll_handle, "eglChooseConfig") == NULL) {
            if (dll_handle != NULL) {
                SDL_UnloadObject(dll_handle);
            }
            return SDL_SetError("Could not load EGL library");
        }
        SDL_ClearError();
    }
#endif

    _this->egl_data->dll_handle = dll_handle;

    /* Load new function pointers */
    LOAD_FUNC(eglGetDisplay);
    LOAD_FUNC(eglInitialize);
    LOAD_FUNC(eglTerminate);
    LOAD_FUNC(eglGetProcAddress);
    LOAD_FUNC(eglChooseConfig);
    LOAD_FUNC(eglGetConfigAttrib);
    LOAD_FUNC(eglCreateContext);
    LOAD_FUNC(eglDestroyContext);
    LOAD_FUNC(eglCreateWindowSurface);
    LOAD_FUNC(eglDestroySurface);
    LOAD_FUNC(eglMakeCurrent);
    LOAD_FUNC(eglSwapBuffers);
    LOAD_FUNC(eglSwapInterval);
    LOAD_FUNC(eglWaitNative);
    LOAD_FUNC(eglWaitGL);
    LOAD_FUNC(eglBindAPI);
    LOAD_FUNC(eglQueryString);
    LOAD_FUNC(eglGetError);

    if (_this->egl_data->eglQueryString) {
        /* EGL 1.5 allows querying for client version */
        const char *egl_version = _this->egl_data->eglQueryString(EGL_NO_DISPLAY, EGL_VERSION);
        if (egl_version != NULL) {
            if (SDL_sscanf(egl_version, "%d.%d", &egl_version_major, &egl_version_minor) != 2) {
                egl_version_major = 0;
                egl_version_minor = 0;
                SDL_LogWarn(SDL_LOG_CATEGORY_VIDEO, "Could not parse EGL version string: %s", egl_version);
            }
        }
    }

    if (egl_version_major == 1 && egl_version_minor == 5) {
        LOAD_FUNC(eglGetPlatformDisplay);
    }

    _this->egl_data->egl_display = EGL_NO_DISPLAY;
#if !defined(__WINRT__)
    if (platform) {
        if (egl_version_major == 1 && egl_version_minor == 5) {
            _this->egl_data->egl_display = _this->egl_data->eglGetPlatformDisplay(platform, (void *)(size_t)native_display, NULL);
        } else {
            if (SDL_EGL_HasExtension(_this, SDL_EGL_CLIENT_EXTENSION, "EGL_EXT_platform_base")) {
                _this->egl_data->eglGetPlatformDisplayEXT = SDL_EGL_GetProcAddress(_this, "eglGetPlatformDisplayEXT");
                if (_this->egl_data->eglGetPlatformDisplayEXT) {
                    _this->egl_data->egl_display = _this->egl_data->eglGetPlatformDisplayEXT(platform, (void *)(size_t)native_display, NULL);
                }
            }
        }
    }
    /* Try the implementation-specific eglGetDisplay even if eglGetPlatformDisplay fails */
    if (_this->egl_data->egl_display == EGL_NO_DISPLAY) {
        _this->egl_data->egl_display = _this->egl_data->eglGetDisplay(native_display);
    }
    if (_this->egl_data->egl_display == EGL_NO_DISPLAY) {
        return SDL_SetError("Could not get EGL display");
    }
    
    if (_this->egl_data->eglInitialize(_this->egl_data->egl_display, NULL, NULL) != EGL_TRUE) {
        return SDL_SetError("Could not initialize EGL");
    }
#endif

    if (path) {
        SDL_strlcpy(_this->gl_config.driver_path, path, sizeof(_this->gl_config.driver_path) - 1);
    } else {
        *_this->gl_config.driver_path = '\0';
    }
    
    return 0;
}
Exemple #6
0
SDL_GLContext
SDL_EGL_CreateContext(_THIS, EGLSurface egl_surface)
{
    /* max 14 values plus terminator. */
    EGLint attribs[15];
    int attr = 0;

    EGLContext egl_context, share_context = EGL_NO_CONTEXT;
    EGLint profile_mask = _this->gl_config.profile_mask;
    EGLint major_version = _this->gl_config.major_version;
    EGLint minor_version = _this->gl_config.minor_version;
    SDL_bool profile_es = (profile_mask == SDL_GL_CONTEXT_PROFILE_ES);

    if (!_this->egl_data) {
        /* The EGL library wasn't loaded, SDL_GetError() should have info */
        return NULL;
    }

    if (_this->gl_config.share_with_current_context) {
        share_context = (EGLContext)SDL_GL_GetCurrentContext();
    }

#if SDL_VIDEO_DRIVER_ANDROID
    if ((_this->gl_config.flags & SDL_GL_CONTEXT_DEBUG_FLAG) != 0) {
        /* If SDL_GL_CONTEXT_DEBUG_FLAG is set but EGL_KHR_debug unsupported, unset.
         * This is required because some Android devices like to complain about it
         * by "silently" failing, logging a hint which could be easily overlooked:
         * E/libEGL  (26984): validate_display:255 error 3008 (EGL_BAD_DISPLAY)
         * The following explicitly checks for EGL_KHR_debug before EGL 1.5
         */
        int egl_version_major = _this->egl_data->egl_version_major;
        int egl_version_minor = _this->egl_data->egl_version_minor;
        if (((egl_version_major < 1) || (egl_version_major == 1 && egl_version_minor < 5)) &&
            !SDL_EGL_HasExtension(_this, SDL_EGL_DISPLAY_EXTENSION, "EGL_KHR_debug")) {
            /* SDL profile bits match EGL profile bits. */
            _this->gl_config.flags &= ~SDL_GL_CONTEXT_DEBUG_FLAG;
        }
    }
#endif

    /* Set the context version and other attributes. */
    if ((major_version < 3 || (minor_version == 0 && profile_es)) &&
        _this->gl_config.flags == 0 &&
        (profile_mask == 0 || profile_es)) {
        /* Create a context without using EGL_KHR_create_context attribs.
         * When creating a GLES context without EGL_KHR_create_context we can
         * only specify the major version. When creating a desktop GL context
         * we can't specify any version, so we only try in that case when the
         * version is less than 3.0 (matches SDL's GLX/WGL behavior.)
         */
        if (profile_es) {
            attribs[attr++] = EGL_CONTEXT_CLIENT_VERSION;
            attribs[attr++] = SDL_max(major_version, 1);
        }
    } else {
#ifdef EGL_KHR_create_context
        /* The Major/minor version, context profiles, and context flags can
         * only be specified when this extension is available.
         */
        if (SDL_EGL_HasExtension(_this, SDL_EGL_DISPLAY_EXTENSION, "EGL_KHR_create_context")) {
            attribs[attr++] = EGL_CONTEXT_MAJOR_VERSION_KHR;
            attribs[attr++] = major_version;
            attribs[attr++] = EGL_CONTEXT_MINOR_VERSION_KHR;
            attribs[attr++] = minor_version;

            /* SDL profile bits match EGL profile bits. */
            if (profile_mask != 0 && profile_mask != SDL_GL_CONTEXT_PROFILE_ES) {
                attribs[attr++] = EGL_CONTEXT_OPENGL_PROFILE_MASK_KHR;
                attribs[attr++] = profile_mask;
            }

            /* SDL flags match EGL flags. */
            if (_this->gl_config.flags != 0) {
                attribs[attr++] = EGL_CONTEXT_FLAGS_KHR;
                attribs[attr++] = _this->gl_config.flags;
            }
        } else
#endif /* EGL_KHR_create_context */
        {
            SDL_SetError("Could not create EGL context (context attributes are not supported)");
            return NULL;
        }
    }

    if (_this->gl_config.no_error) {
#ifdef EGL_KHR_create_context_no_error
        if (SDL_EGL_HasExtension(_this, SDL_EGL_DISPLAY_EXTENSION, "EGL_KHR_create_context_no_error")) {
            attribs[attr++] = EGL_CONTEXT_OPENGL_NO_ERROR_KHR;
            attribs[attr++] = _this->gl_config.no_error;
        } else
#endif
        {
            SDL_SetError("EGL implementation does not support no_error contexts");
            return NULL;
        }
    }

    attribs[attr++] = EGL_NONE;

    /* Bind the API */
    if (profile_es) {
        _this->egl_data->eglBindAPI(EGL_OPENGL_ES_API);
    } else {
        _this->egl_data->eglBindAPI(EGL_OPENGL_API);
    }

    egl_context = _this->egl_data->eglCreateContext(_this->egl_data->egl_display,
                                      _this->egl_data->egl_config,
                                      share_context, attribs);

    if (egl_context == EGL_NO_CONTEXT) {
        SDL_EGL_SetError("Could not create EGL context", "eglCreateContext");
        return NULL;
    }

    _this->egl_data->egl_swapinterval = 0;

    if (SDL_EGL_MakeCurrent(_this, egl_surface, egl_context) < 0) {
        /* Save the SDL error set by SDL_EGL_MakeCurrent */
        char errorText[1024];
        SDL_strlcpy(errorText, SDL_GetError(), SDL_arraysize(errorText));

        /* Delete the context, which may alter the value returned by SDL_GetError() */
        SDL_EGL_DeleteContext(_this, egl_context);

        /* Restore the SDL error */
        SDL_SetError("%s", errorText);

        return NULL;
    }

    return (SDL_GLContext) egl_context;
}