Have you tried some of the old "Graphics Gems" series books yet? [1], [2], [3] They are not CS fundamentals but will help you out with the necessary concepts, math and algorithms for graphics programming and ray-tracing.

As others have mentioned any books on Data Structures & Algorithms are a must. [4], [5], [6]

However in my opinion, trying to understand CS fundamentals without undergoing some sort of formal education is a chore. You won't know what you are missing. Going through an established approved syllabus will give you a fuller understanding. But that is only if you are interested in the long haul.

There are a number of MOOCs that may fit the bill allowing you to slowly gather the knowledge without sacrificing too much time and focus on a day job to keep you going. I feel they are also great value for money for what you get. Some of them are from very reputable names if that is important. [7][8].

Since you have a B.Sc you can do the Masters level but there are also Bachelors level courses. [9]

1. https://www.amazon.com/Graphics-Gems-Andrew-S-Glassner/dp/01...

2. https://www.amazon.com/Graphics-Gems-II-IBM-No/dp/0120644819...

3. https://www.amazon.com/Graphics-Gems-No-3-David-Kirk/dp/0124...

4. https://www.amazon.com/Introduction-Algorithms-3rd-MIT-Press...

5. https://www.amazon.com/Algorithms-4th-Robert-Sedgewick/dp/03...

6. https://www.amazon.com/Algorithm-Design-Manual-Steven-Skiena...

7. https://www.coursera.org/degrees/master-of-computer-science-...

8. https://www.coursera.org/degrees/mcit-penn

9. https://www.coursera.org/degrees/bachelor-of-science-compute...

To start with, "The C Programming Langauge", Kernighan & Richie (K & R) [1]. Find the latest edition that you can buy.

I think the primary topic to master in C is pointers. This is where most falter. It takes a few years to "master" (if we ever do). Here I would recommend "Understanding and Using C Pointers", Richard Reese. [2]

If you are interested in networking, any of the classic "TCP/IP Illustrated Vols I/II/III", W. Richard Stevens, [3] contain a ton of C code to implement components of TCP/IP.

If you are interested in Graphics, then "Graphics Gems", Andrew Glassner [4] is a good source.

"An Introduction to GCC", Brian Gough, [5] to understand the tooling and its various bells and whistles.

My learning swimming by jumping into the deep end of the pool experience was realized by learning Windows Programming using the Charles Petzold book and navigating through Microsoft Foundation Classes in the late 80s/early 90s. The state of the art in tooling wasn't that great in those days and I spent months with the book to get things going. This was done after I had built a foundation with K&R and a decent amount of Unix network programming.

I see a lot of the other posts recommend more modern books. But you still need to build your foundation on C and Pointers in particular.

Good luck on your journey.

[1] https://www.amazon.com/Programming-Language-2nd-Brian-Kernig...

[2] https://www.amazon.com/Understanding-Using-Pointers-Techniqu...

[3] https://www.amazon.com/TCP-Illustrated-Protocols-Addison-Wes...

[4] https://www.amazon.com/Graphics-Gems-Andrew-S-Glassner/dp/01...

[5] https://www.amazon.com/Introduction-GCC-GNU-Compilers/dp/095...

Back in the 90s there was a series of books "Graphics Gems" that was a great resource in learning these tricks. Most people are further removed from drawing directly into a frame buffer today,

https://www.amazon.com/Graphics-Gems-Andrew-S-Glassner/dp/01...

Looks like typical apps we all created during the early 90s. I taught my little brother Pascal in what seemed like a few minutes (I think he was in 5th grade) and within a weekend he created a file manager that would blow this one away. My brother is very smart but my point is, coding some DOS games or a file manager is not anything remarkable, even if you only had the manual to work from. Most developers during that time period worked from a manual. We did not have StackExchange, haha. Where do you think RTFM comes from? I'm surprised this is trending. If you want to see what was typical of the early 90s, take a look at the Graphics Gems books http://www.amazon.com/Graphics-Gems-Andrew-S-Glassner/dp/012... every bookstore in the US had Graphics Gems.

For easy reference, this article points to the book, Graphics Gems (Hardcover) by Andrew S. Glassner (Editor) 1990. There are no Amazon reviews for it at http://www.amazon.com/Graphics-Gems-Andrew-S-Glassner/dp/012... .