Thursday, November 27, 2014

Radiosity on an iPhone

I went to Brad Loos' PhD defense earlier this week (and it and the work presented was excellent; congratulate Brad and remind him that "Dr. Loos" sounds like a James Bond villain).  One of the things Brad talked about was modular radiance transport (MRT).  This was one of the most important works in rendering to my mind because it was a serious attempt to "make radiosity work" and in my opinion was the most successful one so far.   The basic idea is to divide the world into boxes with some number of open interfaces.    By some muscular linear algebra and clever representation they make this work very well for environments that are not exactly mazes and have clutter and details and characters.  Brad mentioned in his talk that Kenny Mitchell spearheaded an MRT tech demo game that is free on the apple app store.  This was done at the time of the work and it even worked on my generation 0 iPad, and here's a screen shot:

It is fluid on that old hardware, and REALLY fluid on my newer phone.  Interactive radiosity really does look good (and the underlying approximations can be seen if you pay careful attention, but I would not have guessed this wasn't just a full solution except for how fast it was).  Try it-- it's fun!

Here is a video of it running.

Also, there is a full report on all the tech behind it.

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