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Action:
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Determines whether or not a pattern lies on a given circle.
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Filename:
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kern/kern_scm/pattern_scm.cxx
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Syntax:
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(pattern:circular? pat {face | {center axis}})
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Arg Types:
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pat
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pattern
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face
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face
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center
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position
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axis
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gvector
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Returns:
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boolean
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Description:
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This extension is limited in that the pattern must be defined.
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This extension returns #t if a pattern lies on the circular surface associated with the
face or, alternately, with the combination of
center and
axis. Otherwise, it returns #f.
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pat specifies a pattern.
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face specifies a circular face.
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center and
axis together specify a circular surface.
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Example:
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; pattern:circular?
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; ; choose an axis and a center defining a circle
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(define center (position 5 6 3))
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;; center
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(define normal (gvector 0 0 1))
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;; normal
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; make a pattern
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(define pat (pattern:cylindrical
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center normal 4 10 3))
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;; pat
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; does the result have circular symmetry about center ; and normal?
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(pattern:circular? pat center normal)
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;; #f
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; what about this pattern?
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(set! pat (pattern:elliptical center normal 5))
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;; trans-vec:
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"DOMAIN(VEC(5,6,3)+VEC(0,0,1)
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;; *3*X2,0,3,0,9)"
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;; x-vec:
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"VEC(-1,0,0)*COS
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;; (1.570796326794897*X+0)
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;; +VEC(0,1,0)*SIN(1.570796326794897*X+0)"
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;; y-vec:
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"VEC(0,0,1)"
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;; z-vec:
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"null_law"
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;; scale:
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"null_law"
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;; keep:
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"null_law"
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;; no list]
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(pattern:circular? pat center normal)
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;; #t
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