A simple raytracer written in C. Based on a raytracer written aytracer written by kragen; and on Ray Tracing in One Weekend by Peter Shirley, Trevor David Black, Steve Hollasch. Raytracing Progress Basics (one sphere, on/off color), Rectangular viewport (1s/pix) Basic coloring based on position ("normals") (1s/pix) Add ground (a big sphere) and two more spheres (1s/pix) Add antialiasing (and accidentally zoom out) (10s/pix) Add sky color (10s/pix) Add diffusion (10s/pix) Make diffusion more directional (Lambertian diffusion) and zoom back in (10s/pix) Increase (10x) random samples per pixel (100s/pix) Shift camera slightly to not intersect the ground (100s/pix) Gamma correction (100s/pix) Add color to spheres (100s/pix) Add reflectivity and varied fuzziness parameter (100s/pix) Final Scene (1s/pix, 2s) (10s/pix, 20s) (100s/pix, 3m24s) (1000s/pix, 33m)
(1s/pix, 2s) 
(10s/pix, 20s) 
(100s/pix, 3m24s)
(1000s/pix, 33m)