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|
;;;; turtle-system.lisp
(in-package #:l-system)
;;;(matrix* translate rotate scale)
(export 'f)
(defun turtle-system (list radians)
(iter (with seed = sb-cga:+identity-matrix+)
(with vec = (sb-cga:vec 1.0 0.0 0.0))
(with pile)
(with angle = radians)
(for item in list)
(case item
((f)
(collect
(setf seed
(matrix* seed
(translate vec)))))
((j)
(setf seed
(matrix* seed
(translate vec))))
((+)
(setf vec
(transform-point (vec 0.0 0.0 0.0)
(matrix*
(rotate-around (vec 0.0 0.0 1.0) angle)
(translate vec)))))
((-)
(setf vec
(transform-point (vec 0.0 0.0 0.0)
(matrix*
(rotate-around (vec 0.0 0.0 1.0) (- angle))
(translate vec)))))
((&)
(setf vec
(transform-point (vec 0.0 0.0 0.0)
(matrix*
(rotate-around (vec 0.0 1.0 0.0) angle)
(translate vec)))))
((^)
(setf vec
(transform-point (vec 0.0 0.0 0.0)
(matrix*
(rotate-around (vec 0.0 1.0 0.0) (- angle))
(translate vec)))))
((\ )
(setf vec
(transform-point (vec 0.0 0.0 0.0)
(matrix*
(rotate-around (vec 1.0 0.0 0.0) angle)
(translate vec)))))
((/)
(setf vec
(transform-point (vec 0.0 0.0 0.0)
(matrix*
(rotate-around (vec 1.0 0.0 0.0) (- angle))
(translate vec)))))
(([)
(push (cons seed vec) pile))
((])
(let ((last-state (pop pile)))
(setf seed (first last-state)
vec (rest last-state)))))))
(defun list-of-vectors->list (list-of-vectors)
(iterconcat #'(lambda (matrix)
(concatenate 'list
(sb-cga:transform-point (vec 0.0 0.0 0.0)
matrix)))
list-of-vectors))
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