Water surface sample for iOS

I'm looking for an开发者_开发知识库 water surface effect sample like Pocket pond HD. I have found some tutorials:

• iPhone OpenGL demo water waves
• Waves effect

However, it's sketchy.

It is very simple.

You just have to make a 2D heightmap (2D array of water height at that particular place). With heightmap, you can calculate (approximate, interpolate) a normal at each place depending on the nearest height points.

Then you perform a "simple raytracing". You "refract each ray" depending on normal, intersect it with plane (bottom) and get a color from texture at that place.

Practically: you make a triangle mesh from height map and render those triangles. You can send normals in Vertex Buffer or compute them in Vertex Shader. Raytracing is done in Fragment Shader. Direction of each ray can be (0, 0, 1). You refract it by current normal and scale the result, so Z coordinate equals water depth. The new X and Y coordinates are texture coordinates.

To make an animation, just update the heightmap in time.