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CHAPTER 4 Graphics
Patch B
fB = 1
2
1 4
c2
c1
3
5 c3 c1
c2 4 7 1
6
3 8 2
Patch B
When f B = 0, start a new patch. fB = 2
Patch A
12 9 3
2
1 10 4
c1 c4
c2
11
3 c1
c2 4 1
2
Patch B
fB = 3
FIGURE 4.23 Edge connections in a Coons patch mesh
If the shading dictionary contains a Function entry, the color data for each corner
of a patch must be specified by a single parametric value t rather than by n sepa-
rate color components c1 … cn . All linear interpolation within the mesh is done
using the t values. After interpolation, the results are passed to the function(s)
specified in the Function entry to determine the color at each point.