Real-time screen-space liquid rendering with complex refractions

Particle-based liquid is often rendered only with single refraction in real-time applications, which deteriorates the reality of liquid. We present a screen-space method for rendering particle-based liquids with up to four refractions in real time. Our method separates liquid particles into splashes and aggregations (i.e., liquid bodies), and generates a pair of depth maps of frontand back-facing surfaces for each. We use the depth maps of splashes as they are, but smooth those of aggregations to reduce small bumps. For smoothing depth, we iteratively fit planes locally using moving least-squares, unlike previous filtering-based approaches that cause undesirable refractions around depth boundaries. By calculating refractions with physically-based light attenuation, our method can render liquids more realistically than previous methods.