Games · Advanced
Build a Ray Tracer
Write a physically based ray tracer that renders spheres with diffuse, metal, and glass materials, plus anti-aliasing and depth of field, to an image file.
You build a ray tracer from scratch that casts rays from a virtual camera through each pixel, finds the nearest surface they hit, and computes color by simulating how light scatters off diffuse, metallic, and dielectric materials. You add anti-aliasing through multiple samples per pixel, a defocus-blur camera for depth of field, and gamma correction, then write the result to a PPM or PNG image. It is worth building because it turns the math of vectors, dot products, and probability into a vivid, photorealistic image you can actually look at. It teaches the linear algebra, recursion, and numerical care behind all of computer graphics, and the striking renders make it one of the most memorable projects to show in a portfolio.
What you build
- Casts primary rays from a configurable camera through each pixel
- Computes ray-sphere intersections for a scene of objects
- Shades Lambertian diffuse surfaces with random scatter
- Reflects rays off metal surfaces with adjustable fuzz
- Refracts rays through glass using Snell's law and Schlick's approximation
- Anti-aliases by averaging many samples per pixel
- Simulates depth of field with a defocus-disk camera
What it teaches
- 3D vector math and ray-surface intersection
- Recursion for light bouncing and path tracing
- Material models: Lambertian, metal, and dielectric
- Monte Carlo sampling and anti-aliasing
- Camera models and depth of field
- Gamma correction and image output formats
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Take it further
- Add triangle meshes and a bounding volume hierarchy to render models.
- Add textures, lights, and a sky or environment map.
- Parallelize rendering across threads to speed up frames.
