Path tracing

Started just with a simple RGB screen, after that the first sphere (Hello, Japanese World!) (and transparent cube in the middle just for debug)

First sphere shading using the hit normal, and then first basic withed light shading and reflections

From around 2fps on singlecore to 30fps on a Ryzen 9 5900X after multithreading and optimizations, to path tracing with accumulation and debugging with Release mode instead of Debug: 350 FPS!

Adding a new sphere with different albedo to see the reflections, and clean surface "acne"

Improved path tracing (stochastic) compared to a whitted version ray tracer:

Accumulation example with moving objects and light.