The “multi-touchable” particle system was written by Hai Nguyen and is comprised of 2.4 million particles. The bulk of the math is performed on the GPU of course, using raw GLSL/FBO GPGPU techniques as opposed to CUDA or similar. The fluid sim is computed on the CPU using a custom solver and uploaded to the GPU as a velocity texture.

Yes, obviously ;)

Great writeup on an impressive project.