(Part 2) Best products from r/opengl

The 4th edition only talk about OpenGL 2.1, if you want to learn modern OpenGL ( 3.x ) buy the 5th edition ( http://www.amazon.com/OpenGL-SuperBible-Comprehensive-Tutorial-Reference/dp/0321712617/ref=sr_1_2?s=books&ie=UTF8&qid=1319548380&sr=1-2 ), but it's only about OpenGL 3.3, not 4.x.

The link alexincode gave you is very good even if it's for OpenGL 3.3 too. But, the author seems to keep updating the tutorial, so it's possible to see an update for OpenGL 4.x.

You'll never compete with Unreal or Crytek in terms of features. You can still create something for a specific use case.

I highly recommend this book. OpenGL 4.0 Shading Language Cookbook https://www.amazon.com/dp/1849514763/ref=cm_sw_r_cp_apa_i_p-JQCb4WDAM6G

This book is amazing, BTW: http://www.amazon.com/gp/offer-listing/1133776574/

Raycaster? On Doom? Doom used the BSP technique to determine the walls to draw, here the Wikipedia post
Wolfenstein used a Ray Casting approach: I suggest you the excellent book by Fabien Sanglard about Wolfenstein 3D engine
This will help you, for sure, on understanding pros and cons of that algorithm

OK, so right now I have three books in question (priority in that order):

1. Real-Time Rendering (https://www.amazon.co.uk/Real-Time-Rendering-Third-Edition-Akenine-Moller/dp/1568814240/ref=sr_1_1?ie=UTF8&qid=1361457638&sr=8-1)
   
   
2. Physically based Rendering (Through not out yet) (https://www.amazon.de/Physically-Based-Rendering-Matt-Pharr/dp/0128006455/ref=sr_1_1?ie=UTF8&qid=1474833345&sr=8-1&keywords=physically+based+rendering)
   
   
3. Introduction to Algorithms (Very famous authors, but already know half/most of the algorithms) (https://www.amazon.com/Introduction-Algorithms-3rd-MIT-Press/dp/0262033844/ref=mt_hardcover?_encoding=UTF8&me=)
   
   What do you think?

Ray tracing in a weekend would be a good start. Followed by the pbrt

Beginning Android games. I can't recommend this book enough. Covers OpenGL ES programming, both 2d and 3d with walkthroughs that mimic how one generally thinks of code as opposed to just spewing out an end product and touching on points in hindsight like so many programming books do.

I don't think so, I was talking about this one : http://www.amazon.com/OpenGL-SuperBible-Comprehensive-Tutorial-Reference/dp/0321498828/ref=sr_1_1?ie=UTF8&qid=1319536743&sr=8-1

Almost all of what I know I learned from this book. When I was learning ES 2.0 there was pretty much no reference material on the subject as nobody used it.

Shaders are pretty simple, however they're a pain in the ass as you have to do everything yourself, which is both an advantage and disadvantage.