Online Books

Computational Geometry

• A Primer on Bézier Curves
  Mike 'Pomax' Kamermans
  A free, online book for when you really need to know how to do Bézier things.

• Discrete Differential Geometry: An Applied Introduction
  Keenan Crane

• Geometry Algorithms
  Dan Sunday
  Huge online book with practical geometric algorithms for the software developer, covering Linear Algebra, Intersections, Convex Hulls, Inclusions, Distances etc, and including C++ implementations.

• Geometric Tools for Computer Graphics
  Philip Schneider, David Eberly
  1042 pages of clean and accurate implementations of simple, intermediate and complex geometric problems.

Creative Coding

• The Nature Of Code
  Daniel Shiffman
  Loved by thousands of creative coders around the world.

Raytracing & Pathtracing

• An Introduction To Ray Tracing
  Andrew S. Glassner (Editor)
  The first book on ray-tracing, a true classic from 1989, still holding it's value.

• NVIDIA Ray Tracing Gems
  Eric Haines, Tomas Akenine-Möller,Alexander Keller, Morgan McGuire, Jacob Munkberg, Matt Pharr, Peter Shirley, Ingo Wald, Chris Wyman
  State of the art real-time rendering techniques with DXR and other APIs, by true legends of the industry. Released in April 2019.

• Physically Based Rendering: From Theory To Implementation
  Matt Phar, Wenzel Jakob, Greg Humphreys
  Considered by some the Bible of modern rendering.

• Ray Tracing Minibook Series
  Peter Shirley
  The famous series "Ray Tracing in a Weekend", "Ray Tracing: The next Week", "Ray Tracing: The Rest of your Life", available in a pay-what-you-want format by the author, Peter Shirley.

• Scratch A Pixel
  32 lessons, 166 chapters, 450,000 words and C++ source code, explaining fundamentals, intermediate and advanced concepts of 3D Rendering, from camera and material models, to volumetric path-tracing. Excellent resource.

Game Programming

• Game Design Patterns
  Bob Nystrom
  Excellent and well-explained collection of patterns found in games that make code cleaner, easier to understand, and faster, by Bob Nystrom, an Electronic Arts veteran.

GPU Shaders & GPU Computing

• The Book of Shaders
  Patricio Gonzalez Vivo, Jen Lowe
  A gentle (And downright astonishing) step-by-step guide through the abstract and complex universe of Fragment Shaders.

• NVIDIA GPU Gems 1,2 & 3
  Probably the most in-depth and extensive open resource on modern GPU computing and real-time graphics available.