SDL2 – OpenGL ES

I love Panda3D game engine. But right now this engine is very hard to compile and debug on Microsoft Windows operation system. So as I said some time ago, I begin to develop my own graphics library. Right now it’s based on OpenGL ES and SDL2.
In this article I am going to tell how to initialize OpenGL ES context and how SDL2 helps in this task. We are going to show nothing.

King Nothing

First of all you need to install OpenGL ES3 – GLES 3 libraries. This operation is platform dependant, for Ubuntu Linux you can just type sudo apt-get install libgles2-mesa-dev. To work with OpenGL you need to initialize OpenGL context. There is many ways to do that, by using one of libraries – SDL2, GLFW, GLFM etc. Actually there is no one right way to initialize OpenGL context, but I chose SDL2 because it’s cross-platform solution, code will look same for Windows/*nix/HTML5/iOS/Android/etc.

To install sdl2 on Ubuntu use this command sudo apt-get install libsdl2-dev

So here is OpenGL context initialization code with SDL2:

    SDL_Window *window = SDL_CreateWindow(
            "SDL2 - OGLES",
            SDL_WINDOWPOS_UNDEFINED,
            SDL_WINDOWPOS_UNDEFINED,
            640,
            480,
            SDL_WINDOW_OPENGL
            );
	    

    SDL_GLContext glContext = SDL_GL_CreateContext(window);

After that, you can use any OpenGL calls in that context.

Here is example code for this article:
https://github.com/demensdeum/OpenGLES3-Experiments/tree/master/3sdl-gles
https://github.com/demensdeum/OpenGLES3-Experiments/blob/master/3sdl-gles/sdlgles.cpp

You can build and test it with command cmake . && make && ./SDLGles

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