//========================================================================
// GLFW 3.4 EGL - www.glfw.org
//------------------------------------------------------------------------
// Copyright (c) 2002-2006 Marcus Geelnard
// Copyright (c) 2006-2019 Camilla Löwy <elmindreda@glfw.org>
//
// This software is provided 'as-is', without any express or implied
// warranty. In no event will the authors be held liable for any damages
// arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it
// freely, subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented; you must not
//    claim that you wrote the original software. If you use this software
//    in a product, an acknowledgment in the product documentation would
//    be appreciated but is not required.
//
// 2. Altered source versions must be plainly marked as such, and must not
//    be misrepresented as being the original software.
//
// 3. This notice may not be removed or altered from any source
//    distribution.
//
//========================================================================
// Please use C89 style variable declarations in this file because VS 2010
//========================================================================

#include "internal.h"

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>

// Return a description of the specified EGL error
//
static const char* getEGLErrorString(EGLint error)
{
	switch (error)
	{
	case EGL_SUCCESS:
		return "Success";
	case EGL_NOT_INITIALIZED:
		return "EGL is not or could not be initialized";
	case EGL_BAD_ACCESS:
		return "EGL cannot access a requested resource";
	case EGL_BAD_ALLOC:
		return "EGL failed to allocate resources for the requested operation";
	case EGL_BAD_ATTRIBUTE:
		return "An unrecognized attribute or attribute value was passed in the attribute list";
	case EGL_BAD_CONTEXT:
		return "An EGLContext argument does not name a valid EGL rendering context";
	case EGL_BAD_CONFIG:
		return "An EGLConfig argument does not name a valid EGL frame buffer configuration";
	case EGL_BAD_CURRENT_SURFACE:
		return "The current surface of the calling thread is a window, pixel buffer or pixmap that is no longer valid";
	case EGL_BAD_DISPLAY:
		return "An EGLDisplay argument does not name a valid EGL display connection";
	case EGL_BAD_SURFACE:
		return "An EGLSurface argument does not name a valid surface configured for GL rendering";
	case EGL_BAD_MATCH:
		return "Arguments are inconsistent";
	case EGL_BAD_PARAMETER:
		return "One or more argument values are invalid";
	case EGL_BAD_NATIVE_PIXMAP:
		return "A NativePixmapType argument does not refer to a valid native pixmap";
	case EGL_BAD_NATIVE_WINDOW:
		return "A NativeWindowType argument does not refer to a valid native window";
	case EGL_CONTEXT_LOST:
		return "The application must destroy all contexts and reinitialise";
	default:
		return "ERROR: UNKNOWN EGL ERROR";
	}
}

// Returns the specified attribute of the specified EGLConfig
//
static int getEGLConfigAttrib(EGLConfig config, int attrib)
{
	int value;
	eglGetConfigAttrib(_glfw.egl.display, config, attrib, &value);
	return value;
}

// Return the EGLConfig most closely matching the specified hints
//
static GLFWbool chooseEGLConfig(const _GLFWctxconfig* ctxconfig,
	const _GLFWfbconfig* desired,
	EGLConfig* result)
{
	EGLConfig* nativeConfigs;
	_GLFWfbconfig* usableConfigs;
	const _GLFWfbconfig* closest;
	int i, nativeCount, usableCount;

	eglGetConfigs(_glfw.egl.display, NULL, 0, &nativeCount);
	if (!nativeCount)
	{
		_glfwInputError(GLFW_API_UNAVAILABLE, "EGL: No EGLConfigs returned");
		return GLFW_FALSE;
	}

	nativeConfigs = calloc(nativeCount, sizeof(EGLConfig));
	eglGetConfigs(_glfw.egl.display, nativeConfigs, nativeCount, &nativeCount);

	usableConfigs = calloc(nativeCount, sizeof(_GLFWfbconfig));
	usableCount = 0;

	for (i = 0; i < nativeCount; i++)
	{
		const EGLConfig n = nativeConfigs[i];
		_GLFWfbconfig* u = usableConfigs + usableCount;

		// Only consider RGB(A) EGLConfigs
		if (getEGLConfigAttrib(n, EGL_COLOR_BUFFER_TYPE) != EGL_RGB_BUFFER)
			continue;

		// Only consider window EGLConfigs
		if (!(getEGLConfigAttrib(n, EGL_SURFACE_TYPE) & EGL_WINDOW_BIT))
			continue;

#if defined(_GLFW_X11)
		{
			XVisualInfo vi = { 0 };

			// Only consider EGLConfigs with associated Visuals
			vi.visualid = getEGLConfigAttrib(n, EGL_NATIVE_VISUAL_ID);
			if (!vi.visualid)
				continue;

			if (desired->transparent)
			{
				int count;
				XVisualInfo* vis =
					XGetVisualInfo(_glfw.x11.display, VisualIDMask, &vi, &count);
				if (vis)
				{
					u->transparent = _glfwIsVisualTransparentX11(vis[0].visual);
					XFree(vis);
				}
			}
		}
#endif // _GLFW_X11

		if (ctxconfig->client == GLFW_OPENGL_ES_API)
		{
			if (ctxconfig->major == 1)
			{
				if (!(getEGLConfigAttrib(n, EGL_RENDERABLE_TYPE) & EGL_OPENGL_ES_BIT))
					continue;
			}
			else
			{
				if (!(getEGLConfigAttrib(n, EGL_RENDERABLE_TYPE) & EGL_OPENGL_ES2_BIT))
					continue;
			}
		}
		else if (ctxconfig->client == GLFW_OPENGL_API)
		{
			if (!(getEGLConfigAttrib(n, EGL_RENDERABLE_TYPE) & EGL_OPENGL_BIT))
				continue;
		}

		u->redBits = getEGLConfigAttrib(n, EGL_RED_SIZE);
		u->greenBits = getEGLConfigAttrib(n, EGL_GREEN_SIZE);
		u->blueBits = getEGLConfigAttrib(n, EGL_BLUE_SIZE);

		u->alphaBits = getEGLConfigAttrib(n, EGL_ALPHA_SIZE);
		u->depthBits = getEGLConfigAttrib(n, EGL_DEPTH_SIZE);
		u->stencilBits = getEGLConfigAttrib(n, EGL_STENCIL_SIZE);

		u->samples = getEGLConfigAttrib(n, EGL_SAMPLES);
		u->doublebuffer = GLFW_TRUE;

		u->handle = (uintptr_t)n;
		usableCount++;
	}

	closest = _glfwChooseFBConfig(desired, usableConfigs, usableCount);
	if (closest)
		*result = (EGLConfig)closest->handle;

	free(nativeConfigs);
	free(usableConfigs);

	return closest != NULL;
}

static void makeContextCurrentEGL(_GLFWwindow* window)
{
	if (window)
	{
		if (!eglMakeCurrent(_glfw.egl.display,
			window->context.egl.surface,
			window->context.egl.surface,
			window->context.egl.handle))
		{
			_glfwInputError(GLFW_PLATFORM_ERROR,
				"EGL: Failed to make context current: %s",
				getEGLErrorString(eglGetError()));
			return;
		}
	}
	else
	{
		if (!eglMakeCurrent(_glfw.egl.display,
			EGL_NO_SURFACE,
			EGL_NO_SURFACE,
			EGL_NO_CONTEXT))
		{
			_glfwInputError(GLFW_PLATFORM_ERROR,
				"EGL: Failed to clear current context: %s",
				getEGLErrorString(eglGetError()));
			return;
		}
	}

	_glfwPlatformSetTls(&_glfw.contextSlot, window);
}

static void swapBuffersEGL(_GLFWwindow* window)
{
	if (window != _glfwPlatformGetTls(&_glfw.contextSlot))
	{
		_glfwInputError(GLFW_PLATFORM_ERROR,
			"EGL: The context must be current on the calling thread when swapping buffers");
		return;
	}

	eglSwapBuffers(_glfw.egl.display, window->context.egl.surface);
}

static void swapIntervalEGL(int interval)
{
	eglSwapInterval(_glfw.egl.display, interval);
}

static int extensionSupportedEGL(const char* extension)
{
	const char* extensions = eglQueryString(_glfw.egl.display, EGL_EXTENSIONS);
	if (extensions)
	{
		if (_glfwStringInExtensionString(extension, extensions))
			return GLFW_TRUE;
	}

	return GLFW_FALSE;
}

static GLFWglproc getProcAddressEGL(const char* procname)
{
	_GLFWwindow* window = _glfwPlatformGetTls(&_glfw.contextSlot);

	if (window->context.egl.client)
	{
		GLFWglproc proc = (GLFWglproc)_glfw_dlsym(window->context.egl.client,
			procname);
		if (proc)
			return proc;
	}

	return eglGetProcAddress(procname);
}

static void destroyContextEGL(_GLFWwindow* window)
{
#if defined(_GLFW_X11)
	// NOTE: Do not unload libGL.so.1 while the X11 display is still open,
	//       as it will make XCloseDisplay segfault
	if (window->context.client != GLFW_OPENGL_API)
#endif // _GLFW_X11
	{
		if (window->context.egl.client)
		{
			_glfw_dlclose(window->context.egl.client);
			window->context.egl.client = NULL;
		}
	}

	if (window->context.egl.surface)
	{
		eglDestroySurface(_glfw.egl.display, window->context.egl.surface);
		window->context.egl.surface = EGL_NO_SURFACE;
	}

	if (window->context.egl.handle)
	{
		eglDestroyContext(_glfw.egl.display, window->context.egl.handle);
		window->context.egl.handle = EGL_NO_CONTEXT;
	}
}

//////////////////////////////////////////////////////////////////////////
//////                       GLFW internal API                      //////
//////////////////////////////////////////////////////////////////////////

// Initialize EGL
//
GLFWbool _glfwInitEGL(void)
{
	int i;
	const char* sonames[] =
	{
#if defined(_GLFW_EGL_LIBRARY)
		_GLFW_EGL_LIBRARY,
#elif defined(_GLFW_WIN32)
		"libEGL.dll",
		"EGL.dll",
#elif defined(_GLFW_COCOA)
		"libEGL.dylib",
#elif defined(__CYGWIN__)
		"libEGL-1.so",
#else
		"libEGL.so.1",
#endif
		NULL
	};

	if (_glfw.egl.handle)
		return GLFW_TRUE;

	for (i = 0; sonames[i]; i++)
	{
		_glfw.egl.handle = _glfw_dlopen(sonames[i]);
		if (_glfw.egl.handle)
			break;
	}

	if (!_glfw.egl.handle)
	{
		_glfwInputError(GLFW_API_UNAVAILABLE, "EGL: Library not found");
		return GLFW_FALSE;
	}

	_glfw.egl.prefix = (strncmp(sonames[i], "lib", 3) == 0);

	_glfw.egl.GetConfigAttrib = (PFN_eglGetConfigAttrib)
		_glfw_dlsym(_glfw.egl.handle, "eglGetConfigAttrib");
	_glfw.egl.GetConfigs = (PFN_eglGetConfigs)
		_glfw_dlsym(_glfw.egl.handle, "eglGetConfigs");
	_glfw.egl.GetDisplay = (PFN_eglGetDisplay)
		_glfw_dlsym(_glfw.egl.handle, "eglGetDisplay");
	_glfw.egl.GetError = (PFN_eglGetError)
		_glfw_dlsym(_glfw.egl.handle, "eglGetError");
	_glfw.egl.Initialize = (PFN_eglInitialize)
		_glfw_dlsym(_glfw.egl.handle, "eglInitialize");
	_glfw.egl.Terminate = (PFN_eglTerminate)
		_glfw_dlsym(_glfw.egl.handle, "eglTerminate");
	_glfw.egl.BindAPI = (PFN_eglBindAPI)
		_glfw_dlsym(_glfw.egl.handle, "eglBindAPI");
	_glfw.egl.CreateContext = (PFN_eglCreateContext)
		_glfw_dlsym(_glfw.egl.handle, "eglCreateContext");
	_glfw.egl.DestroySurface = (PFN_eglDestroySurface)
		_glfw_dlsym(_glfw.egl.handle, "eglDestroySurface");
	_glfw.egl.DestroyContext = (PFN_eglDestroyContext)
		_glfw_dlsym(_glfw.egl.handle, "eglDestroyContext");
	_glfw.egl.CreateWindowSurface = (PFN_eglCreateWindowSurface)
		_glfw_dlsym(_glfw.egl.handle, "eglCreateWindowSurface");
	_glfw.egl.MakeCurrent = (PFN_eglMakeCurrent)
		_glfw_dlsym(_glfw.egl.handle, "eglMakeCurrent");
	_glfw.egl.SwapBuffers = (PFN_eglSwapBuffers)
		_glfw_dlsym(_glfw.egl.handle, "eglSwapBuffers");
	_glfw.egl.SwapInterval = (PFN_eglSwapInterval)
		_glfw_dlsym(_glfw.egl.handle, "eglSwapInterval");
	_glfw.egl.QueryString = (PFN_eglQueryString)
		_glfw_dlsym(_glfw.egl.handle, "eglQueryString");
	_glfw.egl.GetProcAddress = (PFN_eglGetProcAddress)
		_glfw_dlsym(_glfw.egl.handle, "eglGetProcAddress");

	if (!_glfw.egl.GetConfigAttrib ||
		!_glfw.egl.GetConfigs ||
		!_glfw.egl.GetDisplay ||
		!_glfw.egl.GetError ||
		!_glfw.egl.Initialize ||
		!_glfw.egl.Terminate ||
		!_glfw.egl.BindAPI ||
		!_glfw.egl.CreateContext ||
		!_glfw.egl.DestroySurface ||
		!_glfw.egl.DestroyContext ||
		!_glfw.egl.CreateWindowSurface ||
		!_glfw.egl.MakeCurrent ||
		!_glfw.egl.SwapBuffers ||
		!_glfw.egl.SwapInterval ||
		!_glfw.egl.QueryString ||
		!_glfw.egl.GetProcAddress)
	{
		_glfwInputError(GLFW_PLATFORM_ERROR,
			"EGL: Failed to load required entry points");

		_glfwTerminateEGL();
		return GLFW_FALSE;
	}

	_glfw.egl.display = eglGetDisplay(_GLFW_EGL_NATIVE_DISPLAY);
	if (_glfw.egl.display == EGL_NO_DISPLAY)
	{
		_glfwInputError(GLFW_API_UNAVAILABLE,
			"EGL: Failed to get EGL display: %s",
			getEGLErrorString(eglGetError()));

		_glfwTerminateEGL();
		return GLFW_FALSE;
	}

	if (!eglInitialize(_glfw.egl.display, &_glfw.egl.major, &_glfw.egl.minor))
	{
		_glfwInputError(GLFW_API_UNAVAILABLE,
			"EGL: Failed to initialize EGL: %s",
			getEGLErrorString(eglGetError()));

		_glfwTerminateEGL();
		return GLFW_FALSE;
	}

	_glfw.egl.KHR_create_context =
		extensionSupportedEGL("EGL_KHR_create_context");
	_glfw.egl.KHR_create_context_no_error =
		extensionSupportedEGL("EGL_KHR_create_context_no_error");
	_glfw.egl.KHR_gl_colorspace =
		extensionSupportedEGL("EGL_KHR_gl_colorspace");
	_glfw.egl.KHR_get_all_proc_addresses =
		extensionSupportedEGL("EGL_KHR_get_all_proc_addresses");
	_glfw.egl.KHR_context_flush_control =
		extensionSupportedEGL("EGL_KHR_context_flush_control");

	return GLFW_TRUE;
}

// Terminate EGL
//
void _glfwTerminateEGL(void)
{
	if (_glfw.egl.display)
	{
		eglTerminate(_glfw.egl.display);
		_glfw.egl.display = EGL_NO_DISPLAY;
	}

	if (_glfw.egl.handle)
	{
		_glfw_dlclose(_glfw.egl.handle);
		_glfw.egl.handle = NULL;
	}
}

#define setAttrib(a, v) \
{ \
    assert(((size_t) index + 1) < sizeof(attribs) / sizeof(attribs[0])); \
    attribs[index++] = a; \
    attribs[index++] = v; \
}

// Create the OpenGL or OpenGL ES context
//
GLFWbool _glfwCreateContextEGL(_GLFWwindow* window,
	const _GLFWctxconfig* ctxconfig,
	const _GLFWfbconfig* fbconfig)
{
	EGLint attribs[40];
	EGLConfig config;
	EGLContext share = NULL;
	int index = 0;

	if (!_glfw.egl.display)
	{
		_glfwInputError(GLFW_API_UNAVAILABLE, "EGL: API not available");
		return GLFW_FALSE;
	}

	if (ctxconfig->share)
		share = ctxconfig->share->context.egl.handle;

	if (!chooseEGLConfig(ctxconfig, fbconfig, &config))
	{
		_glfwInputError(GLFW_FORMAT_UNAVAILABLE,
			"EGL: Failed to find a suitable EGLConfig");
		return GLFW_FALSE;
	}

	if (ctxconfig->client == GLFW_OPENGL_ES_API)
	{
		if (!eglBindAPI(EGL_OPENGL_ES_API))
		{
			_glfwInputError(GLFW_API_UNAVAILABLE,
				"EGL: Failed to bind OpenGL ES: %s",
				getEGLErrorString(eglGetError()));
			return GLFW_FALSE;
		}
	}
	else
	{
		if (!eglBindAPI(EGL_OPENGL_API))
		{
			_glfwInputError(GLFW_API_UNAVAILABLE,
				"EGL: Failed to bind OpenGL: %s",
				getEGLErrorString(eglGetError()));
			return GLFW_FALSE;
		}
	}

	if (_glfw.egl.KHR_create_context)
	{
		int mask = 0, flags = 0;

		if (ctxconfig->client == GLFW_OPENGL_API)
		{
			if (ctxconfig->forward)
				flags |= EGL_CONTEXT_OPENGL_FORWARD_COMPATIBLE_BIT_KHR;

			if (ctxconfig->profile == GLFW_OPENGL_CORE_PROFILE)
				mask |= EGL_CONTEXT_OPENGL_CORE_PROFILE_BIT_KHR;
			else if (ctxconfig->profile == GLFW_OPENGL_COMPAT_PROFILE)
				mask |= EGL_CONTEXT_OPENGL_COMPATIBILITY_PROFILE_BIT_KHR;
		}

		if (ctxconfig->debug)
			flags |= EGL_CONTEXT_OPENGL_DEBUG_BIT_KHR;

		if (ctxconfig->robustness)
		{
			if (ctxconfig->robustness == GLFW_NO_RESET_NOTIFICATION)
			{
				setAttrib(EGL_CONTEXT_OPENGL_RESET_NOTIFICATION_STRATEGY_KHR,
					EGL_NO_RESET_NOTIFICATION_KHR);
			}
			else if (ctxconfig->robustness == GLFW_LOSE_CONTEXT_ON_RESET)
			{
				setAttrib(EGL_CONTEXT_OPENGL_RESET_NOTIFICATION_STRATEGY_KHR,
					EGL_LOSE_CONTEXT_ON_RESET_KHR);
			}

			flags |= EGL_CONTEXT_OPENGL_ROBUST_ACCESS_BIT_KHR;
		}

		if (ctxconfig->noerror)
		{
			if (_glfw.egl.KHR_create_context_no_error)
				setAttrib(EGL_CONTEXT_OPENGL_NO_ERROR_KHR, GLFW_TRUE);
		}

		if (ctxconfig->major != 1 || ctxconfig->minor != 0)
		{
			setAttrib(EGL_CONTEXT_MAJOR_VERSION_KHR, ctxconfig->major);
			setAttrib(EGL_CONTEXT_MINOR_VERSION_KHR, ctxconfig->minor);
		}

		if (mask)
			setAttrib(EGL_CONTEXT_OPENGL_PROFILE_MASK_KHR, mask);

		if (flags)
			setAttrib(EGL_CONTEXT_FLAGS_KHR, flags);
	}
	else
	{
		if (ctxconfig->client == GLFW_OPENGL_ES_API)
			setAttrib(EGL_CONTEXT_CLIENT_VERSION, ctxconfig->major);
	}

	if (_glfw.egl.KHR_context_flush_control)
	{
		if (ctxconfig->release == GLFW_RELEASE_BEHAVIOR_NONE)
		{
			setAttrib(EGL_CONTEXT_RELEASE_BEHAVIOR_KHR,
				EGL_CONTEXT_RELEASE_BEHAVIOR_NONE_KHR);
		}
		else if (ctxconfig->release == GLFW_RELEASE_BEHAVIOR_FLUSH)
		{
			setAttrib(EGL_CONTEXT_RELEASE_BEHAVIOR_KHR,
				EGL_CONTEXT_RELEASE_BEHAVIOR_FLUSH_KHR);
		}
	}

	setAttrib(EGL_NONE, EGL_NONE);

	window->context.egl.handle = eglCreateContext(_glfw.egl.display,
		config, share, attribs);

	if (window->context.egl.handle == EGL_NO_CONTEXT)
	{
		_glfwInputError(GLFW_VERSION_UNAVAILABLE,
			"EGL: Failed to create context: %s",
			getEGLErrorString(eglGetError()));
		return GLFW_FALSE;
	}

	// Set up attributes for surface creation
	{
		int index = 0;

		if (fbconfig->sRGB)
		{
			if (_glfw.egl.KHR_gl_colorspace)
				setAttrib(EGL_GL_COLORSPACE_KHR, EGL_GL_COLORSPACE_SRGB_KHR);
		}

		setAttrib(EGL_NONE, EGL_NONE);
	}

	window->context.egl.surface =
		eglCreateWindowSurface(_glfw.egl.display,
			config,
			_GLFW_EGL_NATIVE_WINDOW,
			attribs);
	if (window->context.egl.surface == EGL_NO_SURFACE)
	{
		_glfwInputError(GLFW_PLATFORM_ERROR,
			"EGL: Failed to create window surface: %s",
			getEGLErrorString(eglGetError()));
		return GLFW_FALSE;
	}

	window->context.egl.config = config;

	// Load the appropriate client library
	if (!_glfw.egl.KHR_get_all_proc_addresses)
	{
		int i;
		const char** sonames;
		const char* es1sonames[] =
		{
#if defined(_GLFW_GLESV1_LIBRARY)
			_GLFW_GLESV1_LIBRARY,
#elif defined(_GLFW_WIN32)
			"GLESv1_CM.dll",
			"libGLES_CM.dll",
#elif defined(_GLFW_COCOA)
			"libGLESv1_CM.dylib",
#else
			"libGLESv1_CM.so.1",
			"libGLES_CM.so.1",
#endif
			NULL
		};
		const char* es2sonames[] =
		{
#if defined(_GLFW_GLESV2_LIBRARY)
			_GLFW_GLESV2_LIBRARY,
#elif defined(_GLFW_WIN32)
			"GLESv2.dll",
			"libGLESv2.dll",
#elif defined(_GLFW_COCOA)
			"libGLESv2.dylib",
#elif defined(__CYGWIN__)
			"libGLESv2-2.so",
#else
			"libGLESv2.so.2",
#endif
			NULL
		};
		const char* glsonames[] =
		{
#if defined(_GLFW_OPENGL_LIBRARY)
			_GLFW_OPENGL_LIBRARY,
#elif defined(_GLFW_WIN32)
#elif defined(_GLFW_COCOA)
#else
			"libGL.so.1",
#endif
			NULL
		};

		if (ctxconfig->client == GLFW_OPENGL_ES_API)
		{
			if (ctxconfig->major == 1)
				sonames = es1sonames;
			else
				sonames = es2sonames;
		}
		else
			sonames = glsonames;

		for (i = 0; sonames[i]; i++)
		{
			// HACK: Match presence of lib prefix to increase chance of finding
			//       a matching pair in the jungle that is Win32 EGL/GLES
			if (_glfw.egl.prefix != (strncmp(sonames[i], "lib", 3) == 0))
				continue;

			window->context.egl.client = _glfw_dlopen(sonames[i]);
			if (window->context.egl.client)
				break;
		}

		if (!window->context.egl.client)
		{
			_glfwInputError(GLFW_API_UNAVAILABLE,
				"EGL: Failed to load client library");
			return GLFW_FALSE;
		}
	}

	window->context.makeCurrent = makeContextCurrentEGL;
	window->context.swapBuffers = swapBuffersEGL;
	window->context.swapInterval = swapIntervalEGL;
	window->context.extensionSupported = extensionSupportedEGL;
	window->context.getProcAddress = getProcAddressEGL;
	window->context.destroy = destroyContextEGL;

	return GLFW_TRUE;
}

#undef setAttrib

// Returns the Visual and depth of the chosen EGLConfig
//
#if defined(_GLFW_X11)
GLFWbool _glfwChooseVisualEGL(const _GLFWwndconfig* wndconfig,
	const _GLFWctxconfig* ctxconfig,
	const _GLFWfbconfig* fbconfig,
	Visual** visual, int* depth)
{
	XVisualInfo* result;
	XVisualInfo desired;
	EGLConfig native;
	EGLint visualID = 0, count = 0;
	const long vimask = VisualScreenMask | VisualIDMask;

	if (!chooseEGLConfig(ctxconfig, fbconfig, &native))
	{
		_glfwInputError(GLFW_FORMAT_UNAVAILABLE,
			"EGL: Failed to find a suitable EGLConfig");
		return GLFW_FALSE;
	}

	eglGetConfigAttrib(_glfw.egl.display, native,
		EGL_NATIVE_VISUAL_ID, &visualID);

	desired.screen = _glfw.x11.screen;
	desired.visualid = visualID;

	result = XGetVisualInfo(_glfw.x11.display, vimask, &desired, &count);
	if (!result)
	{
		_glfwInputError(GLFW_PLATFORM_ERROR,
			"EGL: Failed to retrieve Visual for EGLConfig");
		return GLFW_FALSE;
	}

	*visual = result->visual;
	*depth = result->depth;

	XFree(result);
	return GLFW_TRUE;
}
#endif // _GLFW_X11

//////////////////////////////////////////////////////////////////////////
//////                        GLFW native API                       //////
//////////////////////////////////////////////////////////////////////////

GLFWAPI EGLDisplay glfwGetEGLDisplay(void)
{
	_GLFW_REQUIRE_INIT_OR_RETURN(EGL_NO_DISPLAY);
	return _glfw.egl.display;
}

GLFWAPI EGLContext glfwGetEGLContext(GLFWwindow* handle)
{
	_GLFWwindow* window = (_GLFWwindow*)handle;
	_GLFW_REQUIRE_INIT_OR_RETURN(EGL_NO_CONTEXT);

	if (window->context.client == GLFW_NO_API)
	{
		_glfwInputError(GLFW_NO_WINDOW_CONTEXT, NULL);
		return EGL_NO_CONTEXT;
	}

	return window->context.egl.handle;
}

GLFWAPI EGLSurface glfwGetEGLSurface(GLFWwindow* handle)
{
	_GLFWwindow* window = (_GLFWwindow*)handle;
	_GLFW_REQUIRE_INIT_OR_RETURN(EGL_NO_SURFACE);

	if (window->context.client == GLFW_NO_API)
	{
		_glfwInputError(GLFW_NO_WINDOW_CONTEXT, NULL);
		return EGL_NO_SURFACE;
	}

	return window->context.egl.surface;
}