Real-Time Rendering of Rough Refraction under Dynamically Varying Environmental Lighting

The illumination of rough refraction is challenging due to the complex integrations of scattered lights from multiple directions. Prefiltered environment map is able to eliminate the comprehensive integrations, but the precomputation stage protects it from being adapted into dynamically varying environmental lighting. We propose a real-time method for rendering rough refraction, supporting dynamically changing lighting, geometries and materials. Environment maps are efficiently compressed by summed area table (SAT), whose construction only costs several milliseconds. Meanwhile, rough refraction effects are approximated by our lobe merging method. Solid results of our approach are demonstrated by comparing with ground truth results generated with a path tracing engine.