31 lines
1 KiB
Scheme
31 lines
1 KiB
Scheme
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(define (direction-normal d)
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(let ((a (* 60 0.017453292)))
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(vector (sin (* a d)) (cos (* a d)) 0)))
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(define (build-ngon n)
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(let ((p (build-polygons n 'polygon)))
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(with-primitive p
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(pdata-index-map!
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(lambda (i p)
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(let ((a (* (/ i n) (* 2 3.141))))
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(vector (cos a) (sin a) 0)))
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"p")
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(pdata-map!
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(lambda (t p)
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(let ((p (vtransform p (mmul
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(mrotate (vector 0 0 -90))
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(mscale (vector -1 1 1))))))
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(vsub (vmul p 0.45) (vector 0.5 0.5 0))))
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"t" "p")
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(pdata-copy "t" "tref")
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(pdata-map! (lambda (n) (vector 0 0 1)) "n"))
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p))
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(clear)
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(build-ngon 6)
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(for ((i (in-range 0 6)))
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(with-primitive (build-ribbon 2)
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(hint-wire)
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(pdata-set "p" 0 (vector 0 0 0))
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(pdata-set "p" 1 (vmul (direction-normal i) 2))))
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