Lecture 13: Global Illumination & Path Tracing (21)

The interpretation of this formula is: Given a fix surface point and an outgoing direction, the outgoing radiance equals to the integral of BRDF times incoming irradiance over the entire hemisphere.


It's noticiable that how we calculate radience in the reflected direction is similar to how we derive the irradiance at a particular point. E(p) equals to the integral of incoming radiance over the entire the hemisphere. Here we plug in a BRDF term to scale incoming radiance over all directions to derive the reflected rediance.

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