Ray tracing: A simple shader A simple light source at infinity can be defined as an rgb color, together with an xyz light direction: vec3 lightColor; // rgb vec3 lightDirection; // xyz A diffuse simple surface material can be defined by an rgb "ambient" component, which is independent of any particular light source, and an rgb "diffuse" component, which is added for each light source: vec3 ambient; // rgb vec3 diffuse; // rgb The figure to the right shows a diffuse sphere, where the point at each pixel is computed as: ambient + lightColor * diffuse * max(0, normal • lightDirection)

Ray tracing: Multiple light sources If the scene contains more than one light source, then pixel color for points on the sphere can be computed by: ambient + ∑n ( lightColorn * diffuse * max(0, normal • lightDirectionn) ) where n iterates over the lights in the scene.

At the end of the class we saw a video: The Centrifuge Brain Project

About the code we worked on in class: After you hand in the assignment that is due next Tuesday, I will post the code that we developed in class. It will be useful for doing the assignment which will be due a week later.