Lecture15-directional-occlusion

Lecture15-directional-occlusion - Directional occlusion...

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Directional occlusion
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Lambertian Surface Obeys Lambert’s Law (from physics) : The color, c , of a surface is proportional to the cosine of the angle between the surface normal and the direction of the light source θ θ θ n n n l l l θ cos rs, unit vecto are and if , cos || |||| || that recall , cos = = l n l n l n l n c
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Diffuse Lighting Model Diffuse reflectance color: fraction of light reflected from the surface (RGB) Light color [0,1] (RGB) Ensures positive light, even when θ > 90 What happens if light source is at infinity? Angle between light and the normal Let’s define a lighting model that captures this n l ) , 0 max( l n = l r c c color
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Ambient Term Lambertian model produces black for any surface facing away from the light In reality, light bounces off walls, is scattered in the atmosphere, etc., so surfaces facing away from the light aren’t usually black Add an ambient light term for all “other” light (a hack) to ensure 0  c  1, ca + cl  (1,1,1) )) , 0 max( ( l n c c c c l a r + =
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This note was uploaded on 03/02/2012 for the course C S 455 taught by Professor Jones,m during the Winter '08 term at BYU.

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Lecture15-directional-occlusion - Directional occlusion...

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