Soft Shadows, Blinn-Phong Shading, and Exposure

Posted on October 6, 2009 by Raffi

softshadowsI’m currently starting the process of implementing the photon map data structure into my Global Illumination Ray Tracer (it’s been challenging to come up with a design that allows for some optimizations I have in mind while also being suitable for my multi-threaded implementation) but here is a quick update on my progress since my last post. The rendering backend now uses 64bpc color throughout (overkill, but it doesn’t hurt) as well as an exposure adjustment to give much better color representation, especially in areas of bright light. I’ve also implemented the Blinn-Phong specular shading model into my materials system.

However, the most important recent addition is the implementation of soft shadow rendering using area lights and jittered sampling. Although achieving a low level of noise using this technique requires a large number of shadow rays per sample, the image on the right shows that the end result is quite nice.