Linearly Transformed Cosines

Computer Graphics · Real-Time Shading · 2016 · also: LTC · linearly-transformed-cosines.yaml

Represents a GGX lobe as a linear transform of a clamped cosine, and cosines can be integrated over a polygon in closed form. Turns area- light shading into an analytic evaluation.

• supersedescorrects · extends
• classifiesspecializes · part-of
• substitutes forapproximates · alternative-to
• depends onrequires · validates

Colour is the family; a dashed line is the second member of it.

This node

• approximatesis a cheaper stand-in for Microfacet Modelmakes area-light integrals closed form

References

• Real-Time Polygonal-Light Shading with Linearly Transformed Cosines — Heitz, Dupuy, Hill, Neubelt — 2016 · link