track nanosec.c and fix some things.
Lesson 1: Triangle rasterization and back-face culling—Triangle shader
Lesson 1: Triangle rasterization and back-face culling—First attempt
Lesson 1: Triangle rasterization and back-face culling—Preparation
Lesson 0: Bresenham's Line Drawing Algorithm—Fifth attempt
Lesson 0: Bresenham's Line Drawing Algorithm—Third attempt
Lesson 0: Bresenham's Line Drawing Algorithm—First attempt