A Particle based Real-Time Rain Simulation on the GPU for Generic Scenes

N. Hempe and J. Rossmann (Germany)


Computer Graphics, Modelling of Natural Phenomena,Real-Time Rendering, Virtual Reality


In this paper, we present a particle based rain simulation to render raindrops as well as raindrop splashes at generic scenes in real-time. The whole simulation is calculated on the GPU using methods from modern graphics hardware. There is no need for CPU-based collision detection methods for rain-scene interaction which can be costly for complex scenes or models with high polygon count. As the simulation takes place as a post render process, our method can easily be applied to many different scenarios. Raindrops are organized in a particle engine which is capable of calculating and rendering hundreds and thousands of single raindrops in real-time. In contrast to many other rain simulations, raindrop splashes are rendered to the right position on a surface where a raindrop previously hits the ground. Furthermore, we take raindrop refraction into account to simulate heavy rain. Additional effects like wave decals can also be displayed to improve this appearance. As our simulation is very modular and only consists of a few shaders, the presented rain rendering techniques can easily be replaced by more complex ones if needed.

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