A Fast Relighting Engine for Interactive Cinematic Lighting Design
Reid Gershbein
(Stanford University)
Pat Hanrahan
(Stanford University)
To appear in SIGGRAPH 2000
Abstract:
We present new techniques for interactive cinematic lighting design
of complex scenes that use procedural shaders.
Deep-framebuffers are used to store the
geometric and optical information of the visible surfaces of an
image.
The geometric information is represented as collections
of oriented points, and
the optical information
is represented as bi-directional reflection
distribution functions, or BRDFs.
The BRDFs are generated by
procedurally defined surface texturing functions that spatially vary the
surfaces' appearances.
The deep-framebuffer information is rendered using a multi-pass
algorithm built on the OpenGL graphics pipeline.
In order to handle both physically-correct as well as non-realistic
reflection models used in the film industry,
we factor the BRDF into independent
components that map onto both the lighting and texturing units
of the graphics hardware.
A similar factorization is used to control the lighting distribution.
Using these techniques, lighting calculations can be evaluated 2500 times
faster than previous methods.
This allows lighting changes to be rendered at rates of 20Hz in static
environments that contain millions of objects with dozens of unique
procedurally defined surface properties and scores of lights.
Additional Information Available:
rsg@graphics.stanford.edu