Simulering av regn på vindruta : Att skapa en realtidseffekt med hjälp av GPGPU

Modelling and rendering natural phenomena, such as rain, is an important aspect of creating a realistic driving simulator. Rain is a crucial issue when driving in the real world as it for instance obstructs the driver’s vision. The difficulty is to implement it in a visually appealing way while simultaneously making it look realistic and keeping the computational cost low. In this report, a GPGPU (general-purpose computing on graphical processing units) based approach is presented where the final product is a rain simulation rendered onto a 2D texture, which can then be applied to a surface. The simulated raindrops interact with gravity, wind, a windshield wiper as well as with each other, and are then used to distort the background behind them in a convincing manner. The simulation takes into account multiple physical properties of raindrops and is shown to be suitable to run in real-time. The result is presented in form of a visual demonstration. In conclusion, even though the final simulation is still in its first iteration, it clearly highlights what can be accomplished by utilizing the GPU and the benefits of using a texture-based approach. The appropriate simulation approach will however always depend on the characteristics of the problem and the limitations of the hardware