Uploaded April 2023 | Updated September 2026, 2 weeks ago

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I tried creating a custom ray/path tracing renderer. Featuring: maths, shaders, and cats!
This project was written in C# and HLSL, and uses the Unity game engine.

Support my work (and get early access to new videos and source code) on Patreon or Nebula
* Patreon: patreon.com/SebastianLague
* Nebula: go.nebula.tv/sebastianlague

Source Code:
* GitHub: github.com/SebLague/Ray-Tracing/tree/Episode01

Credits and References:
* raytracing.github.io
* blog.demofox.org/2020/05/25/casual-shadertoy-path-tracing-1-basic-camera-diffuse-emissive
* Music: github.com/SebLague/Misc-Project-Info/blob/main/Coding-Adventures/Ray-Tracing.txt

Chapters:
0:00 Intro
1:08 Cameras and Rays
3:30 The Pixel Shader
5:02 Drawing a Sphere
6:59 Multiple Spheres, and Colour!
8:21 Two Types of Reflections
9:04 Experimenting with Randomness
11:14 Random Hemisphere Directions
14:11 The Trace Function
16:35 Testing Lights
17:55 Chair Thief
18:23 Progressive Rendering
19:54 A Simple Sky
20:49 Lambert’s Cosine Law
22:47 Cosine Weighted Rays
22:36 Triangles
24:52 Some Tests
27:14 Specular Reflections
29:59 Tomatoes and Glossiness
31:57 Blur and Anti-Aliasing
34:42 Depth of Field
37:14 The End