* After reading 1–7 I understand that there is some relationship between shader language and C, but I’m not sure what it is. Can you tell us explicitly? Is GLSL (shader language) C? Is GLSL a subset of C?
* In point #5 you explain preprocessor macros, but you don’t explain why you used one here. You probably don’t want to go off topic just yet, but I would appreciate a sidebar or brief comment explaining why you are including special handling for GL_ES. (My mind goes: Interesting, but why is mobile OpenGL different from non-mobile?)
* Point #6: I hope later in the book you will show us an example of how changing float precision affects things visually. (I sense it’s important, but don’t see how yet, and I recognize it is too soon to address it here.)
* Point #7: I had to read this two times to get that you meant including the period (.) is casting. I haven’t used C, so I didn’t understand that. I am used to Processing/Java-style casting, like:
