notes.txt

Make a checker function
Default texture stuff, remove default textures from Parse function.
camera focus/aperture blur

Rotate sphere texture
Specular highlighting
show lights
change sky
command line parameters
ambient occlusion
shape smoothing

alternate windows? w/ and w/o preserved perspective? TV vs portal.
FindClosest can just find first closer for lighting

https://en.wikipedia.org/wiki/Line%E2%80%93sphere_intersection

https://en.wikipedia.org/wiki/M%C3%B6ller%E2%80%93Trumbore_intersection_algorithm

http://www.scratchapixel.com/lessons/3d-basic-rendering/minimal-ray-tracer-rendering-simple-shapes/ray-plane-and-ray-disk-intersection

http://netpbm.sourceforge.net/doc/ppm.html

http://math.stackexchange.com/questions/13261/how-to-get-a-reflection-vector

https://en.wikipedia.org/wiki/Floyd%E2%80%93Steinberg_dithering