I have a game that runs on mobile devices (OpenGL ES 2.0) and for which I would like to create some sea water using the shaders. Now, the plane on which the sea water texture will be has only 4 vertices and I need it to remain like that (because of performance issues). So, I think, my only option is to simulate the water from the fragment shader. At conceptual level, how should I do it? I must mention I'm a beginner with the programmable pipeline (I barely learned the language, in some extent) and have no idea where should I start.