213 lines
8.1 KiB
Scheme
213 lines
8.1 KiB
Scheme
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(define (draw-profile index profile offset)
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(cond ((not (null? profile))
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(pdata-set! "p" index (vadd (car profile) offset))
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(draw-profile (+ index 1) (cdr profile) offset))))
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(define (transform-profile profile m)
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(cond
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((null? profile) '())
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(else
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(cons (vtransform (car profile) m)
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(transform-profile (cdr profile) m)))))
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; figures out the vector for rotation of the profile
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(define (path-vector first-segment path lv)
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(let* ((v (if (null? (cdr path)) ; last segment?
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lv ; use the last vector used
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(vsub (cadr path) (car path)))) ; use the next point
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(vd (if first-segment v ; first segment?
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(vadd (vmul lv 0.5) ; blend with the last vector
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(vmul v 0.5)))))
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vd))
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(define (extrude-segment index profile path lv)
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(cond ((not (null? path))
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(let ((v (path-vector (zero? index) path lv)))
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(draw-profile index (transform-profile profile
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(mmul
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(maim v (vector 0 1 0))
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(mrotate (vector 0 90 0))))
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(car path))
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v))))
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(define (mmix a b t)
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(vector
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(+ (* (vector-ref a 0) (- 1 t)) (* (vector-ref b 0) t))
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(+ (* (vector-ref a 1) (- 1 t)) (* (vector-ref b 1) t))
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(+ (* (vector-ref a 2) (- 1 t)) (* (vector-ref b 2) t))
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(+ (* (vector-ref a 3) (- 1 t)) (* (vector-ref b 3) t))
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(+ (* (vector-ref a 4) (- 1 t)) (* (vector-ref b 4) t))
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(+ (* (vector-ref a 5) (- 1 t)) (* (vector-ref b 5) t))
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(+ (* (vector-ref a 6) (- 1 t)) (* (vector-ref b 6) t))
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(+ (* (vector-ref a 7) (- 1 t)) (* (vector-ref b 7) t))
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(+ (* (vector-ref a 8) (- 1 t)) (* (vector-ref b 8) t))
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(+ (* (vector-ref a 9) (- 1 t)) (* (vector-ref b 9) t))
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(+ (* (vector-ref a 10) (- 1 t)) (* (vector-ref b 10) t))
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(+ (* (vector-ref a 11) (- 1 t)) (* (vector-ref b 11) t))
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(+ (* (vector-ref a 12) (- 1 t)) (* (vector-ref b 12) t))
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(+ (* (vector-ref a 13) (- 1 t)) (* (vector-ref b 13) t))
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(+ (* (vector-ref a 14) (- 1 t)) (* (vector-ref b 14) t))
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(+ (* (vector-ref a 15) (- 1 t)) (* (vector-ref b 15) t))))
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(define (extrude-segment-blend index profile path lv t)
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(cond ((not (null? path))
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; figure out the vector for rotation of the profile
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(let ((v (path-vector (zero? index) path v)))
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(cond ((null? (cdr path))
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(draw-profile index (transform-profile profile
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(mmul
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(maim v (vector 0 1 0))
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(mrotate (vector 0 90 0))))
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(car path)))
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(else
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(let ((v2 (path-vector (zero? index) (cdr path) v)))
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(draw-profile index (transform-profile profile
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(mmul
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(maim (vmix (vnormalise v) (vnormalise v2) t) (vector 0 1 0))
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(mrotate (vector 0 90 0))))
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(vmix (car path) (vadd (car path) v2) t)))))
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v))))
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(define (extrude index profile path lv)
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(cond ((not (null? path))
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(let ((v (extrude-segment index profile path lv)))
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(extrude (+ index (length profile)) profile (cdr path) v)))))
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(define (stitch-face index count profile-size in)
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(cond
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((eq? 1 count)
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(append in (list (+ (- index profile-size) 1) index (+ index profile-size)
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(+ (- index profile-size) 1 profile-size))))
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(else
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(append
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(list (+ index 1) index
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(+ index profile-size) (+ index profile-size 1))
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(stitch-face (+ index 1) (- count 1) profile-size in)))))
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(define (stitch-indices index profile-size path-size in)
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(cond
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((eq? 1 path-size) in)
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(else
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(append
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(stitch-face index profile-size profile-size '())
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(stitch-indices (+ index profile-size)
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profile-size
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(- path-size 1)
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in)))))
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(define (build-extrusion profile path)
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(let ((p (build-polygons (* (length profile) (length path)) 'quad-list)))
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(with-primitive p
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(poly-set-index (stitch-indices 0 (length profile) (length path) '()))
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(extrude 0 profile path (vector 0 0 0))
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(recalc-normals 0))
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p))
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; partial extrusions are for animating
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(define (build-partial-extrusion profile path)
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(let ((p (build-polygons (* (length profile) (length path)) 'quad-list)))
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(with-primitive p
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(poly-set-index (stitch-indices 0 (length profile) (length path) '())))
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p))
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(define (chop-front l n)
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(cond ((null? l) l)
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(else
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(if (zero? n) (cons (car l) (chop-front (cdr l) n))
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(chop-front (cdr l) (- n 1))))))
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; returns the last vector
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(define (partial-extrude p t v profile path)
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(with-primitive p 0
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(let* ((start (* (floor t) (length profile)))
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(end (* (length path) (length profile)))
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(v (extrude-segment start profile
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(chop-front path (floor t)) v)))
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(when (< t (- (length path) 1))
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(for ((i (in-range (+ start (length profile)) (+ start (* 2 (length profile))))))
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(pdata-set! "p" i (vsub (pdata-ref "p" (- i (length profile)))
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(vmul v (- (floor t) t)))))
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; collapse the yet un-extruded part into the last vert
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(for ((i (in-range (+ start (* (length profile) 2)) end)))
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(pdata-set! "p" i (pdata-get "p" (+ (length profile) start)))))
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(recalc-normals 0)
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v)))
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#;(define (partial-extrude p t v profile path)
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(with-primitive p 0
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(let* ((start (* (floor t) (length profile)))
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(end (* (length path) (length profile)))
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(v (extrude-segment-blend start profile
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(chop-front path (floor t)) v (- (floor t) t))))
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(when (< t (- (length path) 1))
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#;(for ((i (in-range (+ start (length profile)) (+ start (* 2 (length profile))))))
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(pdata-set! "p" i (vsub (pdata-ref "p" (- i (length profile)))
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(vmul v (- (floor t) t)))))
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; collapse the yet un-extruded part into the last vert
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(for ((i (in-range (+ start (* (length profile) 1)) end)))
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(pdata-set! "p" i (pdata-get "p" start))))
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(recalc-normals 0)
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v)))
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(define (build-circle-profile n r)
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(define (_ n c l)
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(cond ((zero? c) l)
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(else
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(let ((a (* (/ c n) (* 2 3.141))))
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(_ n (- c 1)
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(cons (vmul (vector (sin a) (cos a) 0) r) l))))))
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(_ n n '()))
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(clear)
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(define l (make-light 'point 'free))
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(light-diffuse 0 (vector 0 0 0))
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(light-diffuse l (vector 1 1 1))
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(light-position l (vector 50 50 0))
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(light-specular l (vector 1 1 1))
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(define profile (build-circle-profile 12 0.5))
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(define path (build-list 50
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(lambda (n) (vmul (vector (sin (* 0.5 n)) 0 (cos (* 0.5 n))) (+ 0.5 (* 0.2 n))))))
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#;(define path (build-list 10
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(lambda (n) (vector (* 10 (rndf)) 0 (* 3 n)))))
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(define p (with-state
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; (hint-wire)
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(colour (vector 0 0.5 0.5))
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(specular (vector 1 1 1))
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(shinyness 20)
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(build-partial-extrusion profile path)))
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(define v (vector 0 0 0))
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(define (animate)
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(set! v (partial-extrude p (fmod (* 2 (time)) (length path)) v profile path)))
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(every-frame (animate))
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(with-state
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(wire-opacity 0.4)
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(translate (vector 0 0 0))
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(wire-colour (vector 0 0 1))
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(hint-none)
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(hint-wire)
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; (hint-normal)
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(backfacecull 1)
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(point-width 5)
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(build-extrusion profile path)) |