46 lines
1.2 KiB
Plaintext
46 lines
1.2 KiB
Plaintext
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(define-module interpolation
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:exports (lerp lerper stepped-lerper
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point-lerp point-lerper
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bezier2 bezierer2)
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(define-typed (lerp a :number b :number t :number)
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(+ (* t (- b a)) a))
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(define-typed (lerper a :number b :number)
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(define-typed (ret t :number)
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(lerp a b t))
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ret)
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(define-typed (stepped-lerper a :number b :number #steps :number)
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(let ((t 0)
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(dt (/ 1 #steps)))
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(lambda ()
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(let ((res (lerp a b t)))
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(mutate! t (+ t dt))
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res))))
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(define make-point pair)
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(define point->x first)
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(define point->y rest)
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(define (point-lerp p1 p2 t)
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(make-point (lerp (point->x p1) (point->x p2) t)
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(lerp (point->y p1) (point->y p2) t)))
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(define (point-lerper p1 p2)
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(lambda (t) (point-lerp p1 p2 t)))
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(define (bezier2 p1 p2 p3 t)
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(point-lerp (point-lerp p1 p2 t)
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(point-lerp p2 p3 t)
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t))
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(define (bezierer2 p1 p2 p3)
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(let ((lerper1 (point-lerper p1 p2))
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(lerper2 (point-lerper p2 p3)))
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(lambda (t)
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(point-lerp (lerper1 t)
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(lerper2 t) t))))
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)
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