Exercises Chapter 6
1. Suppose we have a unit sphere centered at the origin, x2 + y2 + z2
= 1. There is a light source at (a,b,c). Generate a formula for
finding the color at any point (x,y,z) on the surface of the sphere,
assuming that there is diffuse reflection. Define any additional terms
you introduce.
2. Assuming monochromatic light, compute the intensity of pixel p in the figure below. Doted lines labelled n are the normals to the surfaces.
Intensity of light L = 1.0, Intensity of ambient colour = 0.3, Background colour = 0.4
Material of surface a:
- ka = 0.2
- kd = 0.2
- kr = ks = 0.3
- kt = 0.3
- m (shininess) = 2
Material of surfaces b, c and d:
- ka = 0.2
- kd = 0.3
- kr = ks = 0.5
- kt = 0 (surfaces are opaque)
Also cos(15) = 0.96, cos(30) = 0.87, cos(35) = 0.82, cos(45) = 0.71, cos(60) = 0.5.
3. The diagram below shows a 2D analog of part of a ray traced scene. There are six "surfaces" A,B,C,D,E,F and a number of rays are shown. Based on the behaviour of the rays at the surfaces, identify the kind of reflective property which each surface has.
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Last modified: Tue Oct 02 09:33:17 GMT Daylight Time 2001