Combining Ray Tracing and Radiosity -- Two
pass method:
- Pass1: Enhanced Radiosity - View
Independent [Rushmerier 90]
- handles:
- diffuse - diffuse
- specular-diffuse
- General Equation
* - The last two items are only for specular surfaces that can't
see each other.
- Pass2: ``Enhanced Ray-Tracing'' -- View
Dependent
- specular-specular -- normal ray tracing
- diffuse-specular:
- Integrate light arriving at reflection point by using a
square pyramid in the direction of specular bump.
- Divide into grid and do a z-buffer at low resolution to
see what is visible -- use radiosity calculated
intensities here.
- can do recursively
- only handles special cases of specular transmission and
specular-diffuse reflection.
Rendering Equation [Kajiya 1986]
where
- I(x,x') = transport intensity (from x' to x)
- g(x,x') = visibility between x and x'
- = transfer
emittance from x' to x.
- = scattering or bidirectional
reflectivity -- intensity of light at x' from
x''scattered in direction x.
- s means all points on all surfaces in the scene.
Interpretation:
transport from x' to x = sum of light
emitted from x' in direction of x plus the total light
scattered from x' to x from all other surfaces.
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Last modified: Wed Mar 3 15:16:44 EST 1999