Ray Tracing in One Weekend - The Book Series

I am currently learning how to write a ray tracer from the Ray Tracing in One Weekend series.

Ray Tracing in One Weekend

Building a simple brute-force path tracer

Ray Tracing the Next Week

Adding textures, volumes (like fog), rectangles, instances, lights, and support for lots of objects using a bounding volume hierarchy (BVH)

Ray Tracing the Rest of Your Life

Diving into the math of creating a very serious ray tracer