GPU Rainfall

Outdoor video games can improve their realism through weather effects simulation. However, simulating rain can yield many problems. We present solutions to address these problems and describe a complete framework to simulate rainfall in a video game. Rendering uses shaders to refract the scene inside the raindrops, based on optical properties. Retinal persistence is also considered. Animation is entirely conducted on graphics hardware, taking into account collisions and wind advection. An interface is presented, which allows the creation of complex wind fields by the user. Videos and shaders are available online.