In my first post I wrote about a team at Stanford University that created a raytracing algorithm called the Hybrid Particle Level Set Method for rendering images, treating the object when appropriate as either a liquid or as composed of tiny metaballs. Although this method was groundbreaking enough to win an Oscar, the bounds of creating realism had still not yet been reached.

Into the picture steps a team of computer scientists from UC San Diego with new raytracing algorithm that vastly cuts the computing costs for smoky and foggy images, thus allowing for much more realistic 3-D scenes. Traditional raytracing methods calculate the light at thousands of points, while the new method, called photon mapping, calculates the entire lightray in one shot. One of the co-authors explains, “Instead of computing the light at thousands of discrete points along the ray between the camera and the object, which is the conventional approach, we compute the lighting along the whole length of the ray all at once.”

Although the more costly raytracing methods may be adequate for scenarios such as movies, there simply isn’t enough computer power to effectively render images in near real-time as required in video games. However, the photon mapping method is much more apt for use in video games due to its much higher efficiency.

Below are two images of a lighthouse in fog, both rendered with the same computational resources. The top image, which is clearly more realistic, was rendered with the new photon mapping method.

http://www.jacobsschool.ucsd.edu/news/news_releases/release.sfe?id=731

http://graphics.ucsd.edu/~wjarosz/publications/jarosz08beam.pdf