breathing, tail swing, process scripts

chain2.js

@@ -0,0 +1,58 @@
+let vec = p5.Vector
+
+class ConstraintPoint {
+  constructor(x, y, size) {
+    this.size = size;
+    this.pos = new vec(x, y);
+    this.forward = new vec(0, 0);
+  }
+
+  follow(targetX, targetY, prevForward = null) {
+    let target = new vec(targetX, targetY);
+    let targetForward = vec.sub(target, this.pos);
+    let targetAngle = targetForward.heading();
+
+    
+
+    if (prevForward) {
+      let a = targetAngle - prevForward;
+      while (a > PI) { a -= TWO_PI; }
+      while (a < -PI) { a += TWO_PI; }
+
+      a = constrain(a, -0.3, 0.3);
+
+      targetAngle = prevForward + a;
+    }
+
+    this.forward = vec.fromAngle(targetAngle);
+    let dir = vec.mult(this.forward, -this.size);
+    this.pos = vec.add(target, dir);
+    
+    
+  }
+}
+
+let points = []
+function setup() {
+  createCanvas(400, 400);
+  
+  for (let i = 0;i < 10;i++) {
+    points.push(new ConstraintPoint(0, 0, 20));
+  }
+}
+
+
+function draw() {
+  background(220);
+  
+  points[0].follow(mouseX, mouseY)
+  for (let i = 1;i < 10;i++) {
+    let prev = points[i - 1];
+    points[i].follow(prev.pos.x, prev.pos.y, prev.forward.heading());
+  }
+  for (let i = 0;i < 10;i++) {
+    let pos = points[i].pos;
+    noFill();
+    circle(pos.x, pos.y, 40);
+  }
+}