I have now been posting these demoes for about 9 months. According to blog stats, your most popular search terms leading here are ‘Metaballs’ and ‘Pixel Bender’ – so I think it’s about time to combine those two !
To render blobs aka metaballs with Pixel Bender I came up with a slightly different algorithm – to avoid the problems with solving an implicit equation in real time rendering. First a weighted average of the distances to each blob – eight of those – is counted, then the output is rendered as a spherical surface. You will find more information on the comments of the code.
The blobs have diffuse rendering with a specular highlight by a fast Blinn-Phong -algorithm, and abilities to adjust the position of light source, colors for the material, shadow and light. In the demo you can choose from some preset materials – looking like oil, chocolate, blood etc … – on the left on the player. You can use mouse pointer as a torch, and clicking changes the rotations.