Shader books suitable for codea shader newb

Hi all, I want to dive into shaders a bit more and I was wondering if you have any suggestions for books? As I’ve only dabbled with shaders in codea I’m not sure on the differences in implementation. So in particular I’m looking for a book which easily translates to codea’s use of shaders.

Start with @Ignatz 's shader e-book

In terms of what kinds of shader are relevant to Codea, it uses Open GLES Shader Language/ Open GLES SL (the ES means its the mobile version of Open GL). If you have an iPad Air or newer, Codea supports Open GLES SL v3.0, otherwise v2.0.

There are some amazing shader resources online too that render the shader results in your browser, eg

Excellent, thanks!