[Progress]Path Tracing

After I review the whole concept about path tracing, now I'm more aware of it.

1. Original path tracing doesn't separate direct illumination part from indirect illumination part.

2. Direct illumination part is for smoothing the result. (Because if the sampled ray doesn't hit the luminaire, it'll be totally black and otherwise it'll be really bright.)

Here is the result. Path tracing with a glass ball.

Parameters:

1 shadow ray

1 hemisphere sample

15 times max bounce (if none of bounces hits the light)

200 samples per pixel