1 files changed, 78 insertions, 0 deletions
diff --git a/sketches/08/tree.rkt b/sketches/08/tree.rkt
new file mode 100644
index 0000000..30ea9d3
--- /dev/null
+++ b/sketches/08/tree.rkt
@@ -0,0 +1,78 @@
+#lang sketching
+
+(require racket/list)
+
+(define (setup)
+  (size 200 200)
+  (frame-rate 20)
+  (loop))
+
+(define Line cons)
+(define ->0 car)
+(define ->1 cdr)
+(define Point cons)
+(define ->x car)
+(define ->y cdr)
+(define Rgb list)
+(define ->r first)
+(define ->g second)
+(define ->b third)
+
+(define (draw/line my-line)
+  (let [ (p1 (->0 my-line)) (p2 (->1 my-line)) ]
+    (line (->x p1) (->y p1) (->x p2) (->y p2))))
+
+;; Parameters
+(define iterations 50)
+(define spoke-ratio 0.6)
+(define total-spokes 8)
+(define max-spoke-depth 10)
+(define (start-length) (/ (min width height) 5))
+(define (start-point) (Point (/ width 2) (/ height 2)))
+(define min-curvature 0.5)
+(define max-curvature 2.0)
+
+;; State
+(define current-iteration 0)
+(define spoke-depth -2)
+(define curvature 0.4)
+
+(define (get-color n)
+  (Rgb
+   (* 255 (+ n 0.9))
+   180 255))
+
+(define (tentacle point len angle spokes)
+  (let [
+        (p2 (Point (+ (->x point) (* len (cos angle)))
+                   (+ (->y point) (* len (sin angle)))))
+        (color (get-color (/ spokes total-spokes) ))
+        ]
+    (stroke (->r color) (->g color) (->b color))
+    (draw/line (Line point p2))
+    (if (> spokes 1)
+        (begin
+          (tentacle p2 (* len spoke-ratio) (+ angle curvature) (- spokes 1))
+          (tentacle p2 (* len spoke-ratio) (- angle curvature) (- spokes 1)))
+        '())))
+
+(define (draw)
+  (color-mode 'hsb 255)
+  (background 0)
+  (stroke-weight 2)
+  (stroke 255 255 255)
+
+  (for-each
+   (lambda (angle)
+     (tentacle (start-point) (start-length) (* angle (/ 2π total-spokes)) spoke-depth))
+   (range 0 total-spokes))
+
+  (if (= current-iteration iterations)
+      (no-loop)
+      (begin
+        (set! current-iteration (+ current-iteration 1))
+        (set! spoke-depth (min (+ spoke-depth 1) max-spoke-depth))
+        (if (> current-iteration 8)
+            (set! curvature (min (max (+ curvature 0.02) min-curvature) max-curvature))
+            '()))))
+