Multigrid fluid solver in OpenGL compute shaders

This is a short clip from a fluid simulation running at 8K internally, displayed on a 6-element, 6K screen. More details: this is a 2D semi-Lagrangian fluid solver in vorticity-streamfunction variables written in OpenGL compute shaders and running at about 10 fps on a dual-GPU machine. The internal solution resolution is 8192x8192, and the vorticity-velocity inversion is done using a multigrid method written entirely in compute shaders (no CUDA, no OpenCL). The advection uses a semi-Lagrangian method that is 2nd order in time and 4th order in space. There is no applied diffusion and limited numerical diffusion. On the left is a convected color scalar field, on the right is the vorticity field. Each field is reduced about 3.5:1 to fit on this 5760x2400 pixel screen. You can try this out on any computer that’s not made by Apple by downloading opengl-with-luajit from