W,A,S,D - Move around
Q,E - Pan left/right
R,F - Look up/down
Mouse - Look around
Left Click - Place gravel
Right Click - Remove block
FPS: --
Note: In order for normal visualization to work, both light sources must be disabled.
Observe: if you place blocks, they are also correctly lit.
Performance is much better here (~30fps on Firefox), with no changes, still using ray tracing.
Seems I would have done much better simply rendering less, or smaller cubes.