Fixed bug 4025 - SDL_Renderer OpenGL : add support for textures ABGR, RGB, BGR

Sylvain

OpenGLES2 SDL renderer has support for textures ARGB, ABGR, RGB and BGR, whereas OpenGL SDL renderer only had ARGB.

If you think it's worth adding it, here's a patch. I quickly tried and it worked, but there may be missing things or corner case.

src/render/opengl/SDL_shaders_gl.h

@@ -31,6 +31,7 @@ typedef enum {
     SHADER_NONE,
     SHADER_SOLID,
     SHADER_RGB,
+    SHADER_RGBA,
     SHADER_YUV_JPEG,
     SHADER_YUV_BT601,
     SHADER_YUV_BT709,