/*

 *  Simple DirectMedia Layer

 *  Copyright (C) 1997-2014 Sam Lantinga <slouken@libsdl.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.

 */

#include "../SDL_internal.h"

#if SDL_VIDEO_OPENGL_EGL

#if SDL_VIDEO_DRIVER_WINDOWS || SDL_VIDEO_DRIVER_WINRT

#include "../core/windows/SDL_windows.h"

#endif

#include "SDL_sysvideo.h"

#include "SDL_egl_c.h"

#include "SDL_loadso.h"

#include "SDL_hints.h"

#if SDL_VIDEO_DRIVER_RPI

/* Raspbian places the OpenGL ES/EGL binaries in a non standard path */

#define DEFAULT_EGL "/opt/vc/lib/libEGL.so"

#define DEFAULT_OGL_ES2 "/opt/vc/lib/libGLESv2.so"

#define DEFAULT_OGL_ES_PVR "/opt/vc/lib/libGLES_CM.so"

#define DEFAULT_OGL_ES "/opt/vc/lib/libGLESv1_CM.so"

#elif SDL_VIDEO_DRIVER_ANDROID

/* Android */

#define DEFAULT_EGL "libEGL.so"

#define DEFAULT_OGL_ES2 "libGLESv2.so"

#define DEFAULT_OGL_ES_PVR "libGLES_CM.so"

#define DEFAULT_OGL_ES "libGLESv1_CM.so"

#elif SDL_VIDEO_DRIVER_WINDOWS || SDL_VIDEO_DRIVER_WINRT

/* EGL AND OpenGL ES support via ANGLE */

#define DEFAULT_EGL "libEGL.dll"

#define DEFAULT_OGL_ES2 "libGLESv2.dll"

#define DEFAULT_OGL_ES_PVR "libGLES_CM.dll"

#define DEFAULT_OGL_ES "libGLESv1_CM.dll"

#else

/* Desktop Linux */

#define DEFAULT_OGL "libGL.so.1"

#define DEFAULT_EGL "libEGL.so.1"

#define DEFAULT_OGL_ES2 "libGLESv2.so.2"

#define DEFAULT_OGL_ES_PVR "libGLES_CM.so.1"

#define DEFAULT_OGL_ES "libGLESv1_CM.so.1"

#endif /* SDL_VIDEO_DRIVER_RPI */

#define LOAD_FUNC(NAME) \

*((void**)&_this->egl_data->NAME) = SDL_LoadFunction(_this->egl_data->dll_handle, #NAME); \

if (!_this->egl_data->NAME) \

{ \

    return SDL_SetError("Could not retrieve EGL function " #NAME); \

}

/* EGL implementation of SDL OpenGL ES support */

static int SDL_EGL_HasExtension(_THIS, const char *ext)

{

    int i;

    int len = 0;

    int ext_len;

    const char *exts;

    const char *ext_word;

    ext_len = SDL_strlen(ext);

    exts = _this->egl_data->eglQueryString(_this->egl_data->egl_display, EGL_EXTENSIONS);

    if(exts) {

        ext_word = exts;

        for(i = 0; exts[i] != 0; i++) {

            if(exts[i] == ' ') {

                if(ext_len == len && !SDL_strncmp(ext_word, ext, len)) {

                    return 1;

                }

                len = 0;

                ext_word = &exts[i + 1];

            }

            else {

                len++;

            }

        }

    }

    return 0;

}

void *

SDL_EGL_GetProcAddress(_THIS, const char *proc)

{

    static char procname[1024];

    void *retval;

    /* eglGetProcAddress is busted on Android http://code.google.com/p/android/issues/detail?id=7681 */

#if !defined(SDL_VIDEO_DRIVER_ANDROID) && !defined(SDL_VIDEO_DRIVER_MIR) 

    if (_this->egl_data->eglGetProcAddress) {

        retval = _this->egl_data->eglGetProcAddress(proc);

        if (retval) {

            return retval;

        }

    }

#endif

    retval = SDL_LoadFunction(_this->egl_data->egl_dll_handle, proc);

    if (!retval && SDL_strlen(proc) <= 1022) {

        procname[0] = '_';

        SDL_strlcpy(procname + 1, proc, 1022);

        retval = SDL_LoadFunction(_this->egl_data->egl_dll_handle, procname);

    }

    return retval;

}

void

SDL_EGL_UnloadLibrary(_THIS)

{

    if (_this->egl_data) {

        if (_this->egl_data->egl_display) {

            _this->egl_data->eglTerminate(_this->egl_data->egl_display);

            _this->egl_data->egl_display = NULL;

        }

        if (_this->egl_data->dll_handle) {

            SDL_UnloadObject(_this->egl_data->dll_handle);

            _this->egl_data->dll_handle = NULL;

        }

        if (_this->egl_data->egl_dll_handle) {

            SDL_UnloadObject(_this->egl_data->egl_dll_handle);

            _this->egl_data->egl_dll_handle = NULL;

        }

        SDL_free(_this->egl_data);

        _this->egl_data = NULL;

    }

}

int

SDL_EGL_LoadLibrary(_THIS, const char *egl_path, NativeDisplayType native_display)

{

    void *dll_handle = NULL, *egl_dll_handle = NULL; /* The naming is counter intuitive, but hey, I just work here -- Gabriel */

    char *path = NULL;

#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) {

        SDL_LoadObject(d3dcompiler);

    }

#endif

    /* 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);

            }

            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);

        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();

    }

    _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);

#if !defined(__WINRT__)

    _this->egl_data->egl_display = _this->egl_data->eglGetDisplay(native_display);

    if (!_this->egl_data->egl_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

    _this->gl_config.driver_loaded = 1;

    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;

}

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) {

        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;

}

SDL_GLContext

SDL_EGL_CreateContext(_THIS, EGLSurface egl_surface)

{

    EGLint context_attrib_list[] = {

        EGL_CONTEXT_CLIENT_VERSION,

        1,

        EGL_NONE,

        EGL_NONE,

        EGL_NONE,

        EGL_NONE,

        EGL_NONE

    };

    EGLContext egl_context, share_context = EGL_NO_CONTEXT;

    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();

    }

    /* Bind the API */

    if(_this->gl_config.profile_mask == SDL_GL_CONTEXT_PROFILE_ES) {

        _this->egl_data->eglBindAPI(EGL_OPENGL_ES_API);

        if (_this->gl_config.major_version) {

            context_attrib_list[1] = _this->gl_config.major_version;

        }

        egl_context = _this->egl_data->eglCreateContext(_this->egl_data->egl_display,

                                          _this->egl_data->egl_config,

                                          share_context, context_attrib_list);

    }

    else {

        _this->egl_data->eglBindAPI(EGL_OPENGL_API);

        if(SDL_EGL_HasExtension(_this, "EGL_KHR_create_context")) {

            context_attrib_list[0] = EGL_CONTEXT_MAJOR_VERSION_KHR;

            context_attrib_list[1] = _this->gl_config.major_version;

            context_attrib_list[2] = EGL_CONTEXT_MINOR_VERSION_KHR;

            context_attrib_list[3] = _this->gl_config.minor_version;

            context_attrib_list[4] = EGL_CONTEXT_OPENGL_PROFILE_MASK_KHR;

            switch(_this->gl_config.profile_mask) {

            case SDL_GL_CONTEXT_PROFILE_COMPATIBILITY:

                context_attrib_list[5] = EGL_CONTEXT_OPENGL_COMPATIBILITY_PROFILE_BIT_KHR;

                break;

            case SDL_GL_CONTEXT_PROFILE_CORE:

            default:

                context_attrib_list[5] = EGL_CONTEXT_OPENGL_CORE_PROFILE_BIT_KHR;

                break;

            }

        }

        else {

            context_attrib_list[0] = EGL_NONE;

        }

        egl_context = _this->egl_data->eglCreateContext(_this->egl_data->egl_display,

                                          _this->egl_data->egl_config,

                                          share_context, context_attrib_list);

    }

    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;

}

int

SDL_EGL_MakeCurrent(_THIS, EGLSurface egl_surface, SDL_GLContext context)

{

    EGLContext egl_context = (EGLContext) context;

    if (!_this->egl_data) {

        return SDL_SetError("OpenGL not initialized");

    }

    /* The android emulator crashes badly if you try to eglMakeCurrent 

     * with a valid context and invalid surface, so we have to check for both here.

     */

    if (!egl_context || !egl_surface) {

         _this->egl_data->eglMakeCurrent(_this->egl_data->egl_display, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);

    }

    else {

        if (!_this->egl_data->eglMakeCurrent(_this->egl_data->egl_display,

            egl_surface, egl_surface, egl_context)) {

            return SDL_SetError("Unable to make EGL context current");

        }

    }

    return 0;

}

int

SDL_EGL_SetSwapInterval(_THIS, int interval)

{

    EGLBoolean status;

    if (!_this->egl_data) {

        return SDL_SetError("EGL not initialized");

    }

    status = _this->egl_data->eglSwapInterval(_this->egl_data->egl_display, interval);

    if (status == EGL_TRUE) {

        _this->egl_data->egl_swapinterval = interval;

        return 0;

    }

    return SDL_SetError("Unable to set the EGL swap interval");

}

int

SDL_EGL_GetSwapInterval(_THIS)

{

    if (!_this->egl_data) {

        return SDL_SetError("EGL not initialized");

    }

    return _this->egl_data->egl_swapinterval;

}

void

SDL_EGL_SwapBuffers(_THIS, EGLSurface egl_surface)

{

    _this->egl_data->eglSwapBuffers(_this->egl_data->egl_display, egl_surface);

}

void

SDL_EGL_DeleteContext(_THIS, SDL_GLContext context)

{

    EGLContext egl_context = (EGLContext) context;

    /* Clean up GLES and EGL */

    if (!_this->egl_data) {

        return;

    }

    if (egl_context != NULL && egl_context != EGL_NO_CONTEXT) {

        SDL_EGL_MakeCurrent(_this, NULL, NULL);

        _this->egl_data->eglDestroyContext(_this->egl_data->egl_display, egl_context);

    }

}

EGLSurface *

SDL_EGL_CreateSurface(_THIS, NativeWindowType nw) 

{

    if (SDL_EGL_ChooseConfig(_this) != 0) {

        return EGL_NO_SURFACE;

    }

    return _this->egl_data->eglCreateWindowSurface(

            _this->egl_data->egl_display,

            _this->egl_data->egl_config,

            nw, NULL);

}

void

SDL_EGL_DestroySurface(_THIS, EGLSurface egl_surface) 

{

    if (!_this->egl_data) {

        return;

    }

    if (egl_surface != EGL_NO_SURFACE) {

        _this->egl_data->eglDestroySurface(_this->egl_data->egl_display, egl_surface);

    }

}

#endif /* SDL_VIDEO_OPENGL_EGL */

/* vi: set ts=4 sw=4 expandtab: */