Approximating the Fire Flicker Effect Using Local Dynamic Radiance Maps

Jonathan Metzgar and Sudhanshu Semwal
Published 2012

This is my paper (coauthored with Dr. Sudhanshu Semwal) accepted at WSCG 2012, the 20th International Conference in Central Europe on Computer Graphics, Visualization, and Computer Vision.

Approximating the Fire Flicker Effect Using Local Dynamic Radiance Maps (PDF)

Abstract

Realistic fire and the flicker effect is a complicated process to simulate in realtime and little work has been done to simulate this complicated illumination effect in realtime. Fire is not a directionally uniform source of light but varies in intensity not only with time but also with direction. Most realtime applications use a standard point light source model for local illumination effects and may use a model to change the light source intensity with time but not direction. Radiance maps and Precomputed Radiance Transfer (PRT) have been used to increase realism at realtime interactive frame rates. These models approximate global illumination by applying an environment map (typically approximated with spherical harmonics) to get their soft lighting effect. In this paper we present Local Dynamic Radiance Maps (LDRM) which uses radiance maps in a local illumination model. We implemented a realtime rendering engine that supports shadow mapping and the physically based Cook-Torrance model to approximate global illumination. In particular, we generate dynamic radiance maps using Perlin noise to simulate the nonlinear radiance of fire and we also implement a rudimentary Lattice-Boltzmann flame rendering effect. Finally, we show how LDRM can be applied not just to approximating the fire flicker effect, but as a general framework for simulating the illumination properties of other nonlinear light sources.