If you want to know all of the math and functions involved in pushing individual pixels to the screen and building something along the lines of a Quake 2-level engine in software, this book is a pretty good introduction to it all:
Note that this is the type of programming now implemented in hardware GPUs, and in libraries such as DirectX and OpenGL. If you were to write a modern game, you would do it on top of one of these hardware-accelerated libraries, and you wouldn't be writing this type of code in software anymore. But if you really want to learn how to do these things from the "ground up", this book can help you build that foundation