Rendering the Real-Time Caustics with DirectX Raytracing

Abstract

Caustic illumination frequently appears in the real life, however, this type of illumination is especially hard to be rendered in real-time. Currently, some solutions allow to render the caustic illumination caused by the water surface, but these methods could not be applied to the arbitrary geometry. In the scope of the current article, we present a method of real-time caustics rendering that uses the DirectX Raytracing API and is integrated into the rendering pipeline. The method is based on using additional forward caustic visibility maps and backward caustics visibility maps that are created for light sources and the virtual camera correspondingly. The article presents the algorithm of the developed real-time caustics rendering method and the results of testing its implementation on test scenes. The analysis of the dependence of the rendering speed on the depth of specular ray tracing, the number of light sources, and the number of rays per pixel is carried out. Testing shows promising results which can be used in the modern game industry to increase the realism of the virtual world visualization.