The Analysis of Global Illumination Rendering Based on BRDF

The Bi-directional Reflectance Distribution Function (BRDF) describes the appearance of a material by its interaction with light at a surface point. When the materials in scene are invariant, a linear transformation occurs in the transmission change from lighting to outgoing radiance, which makes a real-time global illumination rendering achieved. However, such linear transformation does not hold when materials change. This paper presents a real-time rendering algorithm for scenes with editable materials under direct and indirect illumination. All materials in scenes are represented as various linear combinations of the BRDF base, from which, all outgoing radiance luminance of each combination are pre-computed. When it renders, linear combines the pre-computed data by the coefficient resulted from different materials projection on the base, the nonlinear problem is converted to a linear one, and the final effects of global illumination rendering in real-time can be achieved.