sketch_jul-03-2020_13-38-57.glisp

(defn fix-distance
	[base desire distance]
	(let [angle (vec2/angle (vec2/- desire base))]
              (vec2/rotate base angle (vec2/+ base [distance 0]))))

(defn make-chain
	{:params [{:label "src" :type "any"}
	          {:label "step" :type "number"}
	          {:overwrap "overwrap" :type "number" :default 0}]
	}
	[src step overwrap]
	(for [base (range 0 (- (count src) (dec step)) (- step overwrap))]
      (vec (slice src base (+ base step)))
  )
)
(defn ik-bones
	{:handles
		{:draw
			(fn [{:params [root & params]}]
					(reduce (fn [a b]
						          (concat a (let [index (count a)
                              	length (first b)
                              	angle (second b)
                              	lastPos (get (last a) :pos)
                              	newPos (vec2/+ lastPos (vec2/scale [(cos angle) (sin angle)] length))]
		                        [{:id index
				                      :type "point"
				                      :pos newPos}])))
           [{:id 0 :type "point" :pos root}] params)
      )
     :drag
    	(fn [{:id id :pos p :prev-pos pp :params [root & params]}]
    	    (let [delta (vec2/- p pp)
    	          pos (reduce (fn [a b]
						          (concat a (let [
                              	length (first b)
                              	angle (second b)
                              	lastPos (last a)
                              	newPos (vec2/+ lastPos (vec2/scale [(cos angle) (sin angle)] length))
                              	]
		                        [newPos]))) [root] params)
                parents (reverse (reduce (fn [a b] (let [length (first (nth params(- id (count a))))] (concat a [(fix-distance (last a) b length)]))) [p] (reverse (take id pos))))
                children (reduce (fn [a b] (let [length (first (nth params (+ id (dec (count a)))))] (concat a [(fix-distance (last a) b length)]))) [p] (drop (inc id) pos))
              	moved (concat parents (rest children))
               ]
               (concat [root] (reduce (fn [a b] 
                                 (let [index (count a)
                                       from b
                                       to (nth moved (inc index))
                                       sub (vec2/- to from)
                                       ]
                                    	 (concat a [[(vec2/len sub) (vec2/angle sub)]])
                                      ))
                                 [] (butlast moved)))
								)
    	    )
	}}
	[root & params]
	(let [pos (reduce (fn [a b]
						          (concat a (let [
                              	length (first b)
                              	angle (second b)
                              	lastPos (last a)
                              	newPos (vec2/+ lastPos (vec2/scale [(cos angle) (sin angle)] length))
                              	]
		                        [newPos]))) [root] params)]
		                       (map (fn [[a b]] (line a b)) (make-chain pos 2 1)))
)


:start-sketch

(style (stroke "salmon" 10)
	(ik-bones [0 0] [100.00000000000009 (deg -23.76411514057926)] [80 (deg -167.53793434757057)] [60.00000000000031 (deg 167.08024675208864)] [40.00000000000007 (deg 38.303389912357815)] [20.000000000000288 (deg -1.5189524288203164)])
)