With microfacet brdf models

Stress test with 20 spheres and 3 light sources 1 directional, two point, plus ambient. Renders in 4365ms with 8 core, 16 threads on my 2019 macbook.

Here you can see that the left shadow is messed up despite there being no left wall. This was before finding the fix searching for closest intersection

Got it working. I had to set my pointlight Trace function to find the closest intersection rather than just any. Not sure why there is an issue with that, but I found that the other walls would have an effect for some reason.

First render of box scene. Clearly not working correctly.

smaller epsilon 1e-5 shows more artifacts.

Using epsilon of 1e-3, the artifacts are reduced. What is the best way to set this parameter?

Some artifacts present in the shadow edges on the sphere