Refraction of Water Surface Intersecting Objects in Interactive Environments

This paper presents a rapid method to render dynamic water surfaces with penetrating obstacles in real-time. Taking the surface boundary into account, our method allows the rendering of single reflections and single refractions of objects even intersecting the water surface, including a physically approximative perspective refraction mapping. Thereby, water surfaces are represented as 2.5D height fields and obstacles as polygonal objects. In principle, we determine approximating virtual reflection and refraction eye coordinates. With respect to the water surface, the reflected and refracted objects and parts of objects are projected onto the surface from separate, virtual eye coordinates. Since we are using per-pixel reflection and refraction mapping, our multi-pass, image-based technique is suitable for GPU-based implementations. Moreover, we demonstrate the interactive application of the method for height field based data sets extracted from interactive 3D Smoothed Particle Hydrodynamics (SPH) simulations in real-time. Thereby, the presented approach achieves high frame rates and plausible results.