Week 11 Day 1 - How Color Works
0Today we covered the last math topic, which is on how color works, with both additive and subtractive color. The color that is reflected off an object works like this:
1) Add together the contribution of light from all light sources. If they are not directly facing the surface being lit, use the dot product (cos theta) to see what percentage of light hits the surface. If the light has falloff (such as a point light), reduce the contribution of light based on distance.
2) Multiply each component of light hitting a surface with the color of the surface (sometimes called albedo). A while surface reflects all light perfectly, a dark surface absorbs all light, a 50% grey surface reflects 50% of the incident light, and so forth, with the general rule being this:
"Multiply each component of the incident light with the respective component of the surface color"
So light of color {.5, .8, 1} on a 50% purple surface {0.5, 0, 0.5} would reflect {.25, 0, 0.5} light towards the camera.