src/video/windows/SDL_windowsopengles.c

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2020 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_DRIVER_WINDOWS && SDL_VIDEO_OPENGL_EGL

#include "SDL_windowsvideo.h"
#include "SDL_windowsopengles.h"
#include "SDL_windowsopengl.h"
#include "SDL_assert.h"

/* EGL implementation of SDL OpenGL support */

int
WIN_GLES_LoadLibrary(_THIS, const char *path) {

    /* If the profile requested is not GL ES, switch over to WIN_GL functions  */
    if (_this->gl_config.profile_mask != SDL_GL_CONTEXT_PROFILE_ES) {
#if SDL_VIDEO_OPENGL_WGL
        WIN_GLES_UnloadLibrary(_this);
        _this->GL_LoadLibrary = WIN_GL_LoadLibrary;
        _this->GL_GetProcAddress = WIN_GL_GetProcAddress;
        _this->GL_UnloadLibrary = WIN_GL_UnloadLibrary;
        _this->GL_CreateContext = WIN_GL_CreateContext;
        _this->GL_MakeCurrent = WIN_GL_MakeCurrent;
        _this->GL_SetSwapInterval = WIN_GL_SetSwapInterval;
        _this->GL_GetSwapInterval = WIN_GL_GetSwapInterval;
        _this->GL_SwapWindow = WIN_GL_SwapWindow;
        _this->GL_DeleteContext = WIN_GL_DeleteContext;
        return WIN_GL_LoadLibrary(_this, path);
#else
        return SDL_SetError("SDL not configured with OpenGL/WGL support");
#endif
    }
    
    if (_this->egl_data == NULL) {
        return SDL_EGL_LoadLibrary(_this, NULL, EGL_DEFAULT_DISPLAY, 0);
    }

    return 0;
}

SDL_GLContext
WIN_GLES_CreateContext(_THIS, SDL_Window * window)
{
    SDL_GLContext context;
    SDL_WindowData *data = (SDL_WindowData *)window->driverdata;

#if SDL_VIDEO_OPENGL_WGL
    if (_this->gl_config.profile_mask != SDL_GL_CONTEXT_PROFILE_ES) {
        /* Switch to WGL based functions */
        WIN_GLES_UnloadLibrary(_this);
        _this->GL_LoadLibrary = WIN_GL_LoadLibrary;
        _this->GL_GetProcAddress = WIN_GL_GetProcAddress;
        _this->GL_UnloadLibrary = WIN_GL_UnloadLibrary;
        _this->GL_CreateContext = WIN_GL_CreateContext;
        _this->GL_MakeCurrent = WIN_GL_MakeCurrent;
        _this->GL_SetSwapInterval = WIN_GL_SetSwapInterval;
        _this->GL_GetSwapInterval = WIN_GL_GetSwapInterval;
        _this->GL_SwapWindow = WIN_GL_SwapWindow;
        _this->GL_DeleteContext = WIN_GL_DeleteContext;

        if (WIN_GL_LoadLibrary(_this, NULL) != 0) {
            return NULL;
        }

        return WIN_GL_CreateContext(_this, window);
    }
#endif

    context = SDL_EGL_CreateContext(_this, data->egl_surface);
    return context;
}

void
WIN_GLES_DeleteContext(_THIS, SDL_GLContext context)
{
    SDL_EGL_DeleteContext(_this, context);
    WIN_GLES_UnloadLibrary(_this);
}

SDL_EGL_SwapWindow_impl(WIN)
SDL_EGL_MakeCurrent_impl(WIN)

int
WIN_GLES_SetupWindow(_THIS, SDL_Window * window)
{
    /* The current context is lost in here; save it and reset it. */
    SDL_WindowData *windowdata = (SDL_WindowData *) window->driverdata;
    SDL_Window *current_win = SDL_GL_GetCurrentWindow();
    SDL_GLContext current_ctx = SDL_GL_GetCurrentContext();

    if (_this->egl_data == NULL) {
        SDL_assert(!_this->gl_config.driver_loaded);
        if (SDL_EGL_LoadLibrary(_this, NULL, EGL_DEFAULT_DISPLAY, 0) < 0) {
            SDL_EGL_UnloadLibrary(_this);
            return -1;
        }
        _this->gl_config.driver_loaded = 1;
    }
  
    /* Create the GLES window surface */
    windowdata->egl_surface = SDL_EGL_CreateSurface(_this, (NativeWindowType)windowdata->hwnd);

    if (windowdata->egl_surface == EGL_NO_SURFACE) {
        return SDL_SetError("Could not create GLES window surface");
    }

    return WIN_GLES_MakeCurrent(_this, current_win, current_ctx);    
}

#endif /* SDL_VIDEO_DRIVER_WINDOWS && SDL_VIDEO_OPENGL_EGL */

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