Image-Based Post-processing for Realistic Real-Time Rendering of Scenes in the Presence of Fluid Simulations and Image-Based Lighting

For real-time fluid simulation currently two methods are available: grid-based simulation and particle-based simulation. They both approximate the simulation of a fluid and have in common that they do not directly generate a visually pleasant surface. Due to time constraints, the subsequent generation of the fluid surface may not consume much time. What is usually generated is an approximate surface, which consists of many individual mesh elements and has no optical properties of a fluid. The visualization of a fluid in image space may contain different detail densities depending on the distance between observer and the fluid. Therefore, filters need to be applied in order to smooth these details to a consistent surface. Many approaches use strong filters in this step, which results in a too smooth surface. To this surface then noise is added in order to give it a rough appearance. To avoid this ad-hoc approach we present a post-processing approach of the direct visualization of the simulation data via image processing applications by both smoothing filters and an image pyramid. Our presented approach based on an image pyramid provides access to various levels of detail. These are used as a controllable low pass filter. Thus, different amounts of smoothing can be selected depending on the distance to the viewer, granting a better surface reconstruction.