Here are the outputs I am getting for prog1. I have also worked out shadows with a different set of cubes.
1) Make sure the origin is on the BOTTOM-LEFT Corner of the viewing window.
2) Try out various inputs since you'll be graded with different test files which could have several cubes with occlusions. Test files will not be as simple looking as the sample JSON files that we have provided.
3) Make sure you implement the Ray-casting algorithm and not Rasterization. Loop over pixels first and then Objects.
Part1: Ray cast the colored boxes in the input file without lighting:
Part2: Color the boxes with Blinn-Phong illumination
Extra Credit: With Shadows