In part 2 of this series I explained about how to get the sky. This entry is about how to compute an irradiance environment map from this cubemap.
In Part 1 of this howto, I introduced my demo. In this part I'm going to talk about how to make the sky. The demo also computes an irradiance map and applies it to the cube. I'm going to talk about this in Part 3.
WebGL is now enabled by default in both Firefox 4.0 and Chrome 10.0, so I thought I give it a try and see what I can get out of it. The goal was to render some simple terrain, nice looking sky and waving grass. In this part of the description I will give the overview of how that works.
Since all the excitement about Minecraft I wondered what nice rendering effects could be done in such a restricted environment. I have decided to pursue that avenue of research and a variety of techniques will be presented in the following article.
This article presents a system to integrate verlet physics collision with preservation of impulse. Normally verlet physics annihilates a lot of energy from a system, which makes it very stable but also quite unrealistic. Additionally simple methods of preserving impulse yield very unstable systems, a limitation which can be overcome by two steps of integration, one for at-rest acceleration canceling, and one with impulse preservation.
In this post I'm testing different integration methods for a gravity simulation. The results can be inspected interactively in the canvas tags that accompany each test. Hover with the mouse over the illustration to start its simulation or click the illustration to reset the simulation.