/*

  *  Simple DirectMedia Layer

  *  Copyright (C) 1997-2013 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_config.h"

 #if SDL_VIDEO_OPENGL_EGL

 #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_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 */

 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) 

     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) {

         /* By default we load the Vista+ compatible compiler */

         d3dcompiler = "d3dcompiler_46.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.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);

             }

         }

     }

     _this->egl_data->egl_dll_handle = egl_dll_handle;

     if (egl_dll_handle == NULL) {

         return SDL_SetError("Could not initialize OpenGL ES 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);

     }   

     /* Catch the case where the application isn't linked with EGL */

     if ((SDL_LoadFunction(dll_handle, "eglChooseConfig") == NULL) && (egl_path == 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) {

             return SDL_SetError("Could not load EGL library");

         }

     }

     _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);

     _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");

     }

     _this->egl_data->dll_handle = dll_handle;

     _this->egl_data->egl_dll_handle = egl_dll_handle;

     _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';

     }

     /* We need to select a config here to satisfy some video backends such as X11 */

     return SDL_EGL_ChooseConfig(_this);

 }

 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.major_version == 2) {

         attribs[i++] = EGL_OPENGL_ES2_BIT;

     } else {

         attribs[i++] = EGL_OPENGL_ES_BIT;

     }

     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

     };

     EGLContext egl_context;

     if (!_this->egl_data) {

         /* The EGL library wasn't loaded, SDL_GetError() should have info */

         return NULL;

     }

     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,

                                       EGL_NO_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) 

 {

     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: */