add projected cilia along the original function

src/shimmers/sketches/cilia_phase.cljs

@@ -4,10 +4,13 @@
    [shimmers.common.svg :as csvg :include-macros true]
    [shimmers.common.ui.controls :as ctrl]
    [shimmers.common.ui.svg :as usvg]
+   [shimmers.math.deterministic-random :as dr]
    [shimmers.math.equations :as eq]
    [shimmers.sketch :as sketch :include-macros true]
+   [thi.ng.geom.core :as g]
+   [thi.ng.geom.line :as gl]
    [thi.ng.geom.vector :as gv]
-   [shimmers.math.deterministic-random :as dr]))
+   [thi.ng.math.core :as tm]))
 
 ;; Concept: generate a random phase-shifted function, and then add cilia along
 ;; it's path. Specifically interested in trying to make another phase shifted
@@ -26,14 +29,29 @@
         cx' (dr/random)]
     (fn [x] (math/sin (* eq/TAU (+ (* rx x) cx (* amp (math/cos (* eq/TAU (+ (* rx' x) cx'))))))))))
 
+(defn screen-space [fx x]
+  (rv x (+ 0.5 (* 0.35 (fx x)))))
+
 (defn base-spline [fx]
   (for [x (range 0 1 0.0025)]
-    (rv x (+ 0.5 (* 0.35 (fx x))))))
+    (screen-space fx x)))
+
+;; How to avoid intersecting cilia?
+(defn cilias [fx]
+  (let [spx (spline-fx)]
+    (for [x (range 0 1 0.005)]
+      (let [pt (screen-space fx x)
+            pt' (screen-space fx (+ x 0.0001))
+            len (+ 12 (* 8 (spx x)))
+            offset (tm/normalize (g/rotate (tm/- pt' pt) (* eq/TAU 0.25)) len)]
+        (gl/line2 (tm/+ pt offset) (tm/- pt offset))))))
 
 (defn shapes []
   (let [fx (spline-fx)
-        spline-pts (base-spline fx)]
-    [(csvg/path (csvg/segmented-path spline-pts))]))
+        spline-pts (base-spline fx)
+        cilia (cilias fx)]
+    (concat [(csvg/path (csvg/segmented-path spline-pts))]
+            cilia)))
 
 (defn scene [{:keys [scene-id]}]
   (csvg/svg-timed