Merge pull request #736 from nicolandu/main

fractal_circle-Nicolas_Landucci

Author: maxwofford

art/fractal_circle-Nicolas_Landucci/index.js

@@ -0,0 +1,188 @@
+/*
+@title: Fractal Circle
+@author: Nicolas Landucci
+@snapshot: 0.png
+*/
+
+// Fractal Circle by Nicolas Landucci is GPLv3-licensed.
+// NOTE TO SELF: Arrays are passed by reference. To "duplicate" points,
+// use Array.slice() .
+
+// mm
+const width = 125;
+const height = 125;
+
+// interesting effect (toggle)
+const showSkeleton = true;
+
+// determines next branch length
+function lenMapping(x) {
+  return x * .75;
+}
+
+// length of trunk
+const initialLen =14;
+
+// determines branch length threshold
+const minLen = 1;
+const angle = 20;
+
+// base value
+const randomFactor = 0.05;
+// how much randomFactor increases at each sample on a branch
+const randomFactorProgression = 0.05;
+
+const circleRadius = 55;
+const circlePointCount = 3000;
+const circleRandomFactor = 2;
+const drawCircle = true;
+
+const signaturePointPositionRandomFactor = 0.05;
+const signaturePositionRandomFactor = 0.5;
+const signatureRotationRandomFactor = 2;
+const jitterSignature = true;
+const jitterInterval = 0.002;
+const jitterRandomFactor = 0.5;
+
+// we only use the Turtle to measure lines, not to draw them, unless showSkeleton is active
+// in any case, pen down is OK
+const t = new bt.Turtle()
+  .left(90)
+  .down();
+
+setDocDimensions(width, height);
+
+// store final lines here
+const finalLines = [];
+
+const allLines = [];
+
+function rec(x) {
+  if (x < minLen) return;
+  const line = [];
+  const initialPos = t.pos;
+  const initialAngle = t.angle;
+  line.push(t.pos);
+  for (let i = 0; i < 3; i++) {
+    t.forward(x / 4);
+    t.left(90);
+    const step = bt.randInRange(
+      -randomFactor * x - randomFactorProgression * i * x,
+      randomFactor * x + randomFactorProgression * i * x
+    );
+    t.forward(step);
+    line.push(t.pos);
+    t.forward(-step);
+    t.right(90);
+  }
+  t.forward(x / 4);
+  line.push(t.pos);
+
+  allLines.push(line);
+  t.left(angle);
+  rec(lenMapping(x));
+  t.right(2 * angle);
+  rec(lenMapping(x));
+  t.jump(initialPos);
+  t.setAngle(initialAngle);
+}
+
+for (let i = 0; i < 6; i++) {
+  rec(initialLen);
+  t.right(60);
+}
+for (let line in allLines) {
+  const tmp = [bt.catmullRom(allLines[line])];
+  bt.join(finalLines, tmp);
+}
+
+if (showSkeleton) bt.join(finalLines, t.path);
+
+if (drawCircle) {
+  const circlePoints = [];
+  for (let i=0; i<circlePointCount; i++) {
+    const val = bt.randInRange(-circleRandomFactor,circleRandomFactor);
+    circlePoints.push([Math.cos(i*2*Math.PI/circlePointCount)*(circleRadius+val),
+                       Math.sin(i*2*Math.PI/circlePointCount)*(circleRadius+val)]);
+  }
+  // close the circle
+  circlePoints.push(circlePoints[0].slice());
+  bt.join(finalLines, [circlePoints]);
+}
+
+bt.translate(
+  finalLines,
+  [width / 2, height / 2],
+  bt.bounds(finalLines).cc
+);
+
+const signaturePoints = [
+  [-2.07, 1.26],
+  [0, 2],
+  [1.33, 3.4],
+  [1.22, 4.65],
+  [0.18, 5.5],
+  [-0.93, 4.29],
+  [-1.64, -1.8],
+  [-0.68, 0.79],
+  [0.54, 1.06],
+  [1.67, -2],
+  [3.49, -1.29],
+  [4.84, 2.55],
+  [3.41, 6.11],
+  [-1.22, 7.39],
+  [-4.14, 4.86],
+  [-4.5, 1.76],
+  [-3.44, -1.43],
+];
+
+for (let i = 0; i < signaturePoints.length; i++) {
+  signaturePoints[i][0] += bt.randInRange(
+    -signaturePointPositionRandomFactor,
+    signaturePointPositionRandomFactor);
+  signaturePoints[i][1] += bt.randInRange(
+    -signaturePointPositionRandomFactor,
+    signaturePointPositionRandomFactor);
+}
+
+const signatureBase = bt.catmullRom(signaturePoints);
+let signature = [];
+
+if (jitterSignature) {
+  for (let i = 0; i <= 1; i+=jitterInterval) {
+    const val = bt.randInRange(-jitterRandomFactor,jitterRandomFactor);
+    const point = bt.getPoint([signatureBase], i);
+    const normal = bt.getNormal([signatureBase], i);
+    signature.push([
+      point[0]+normal[0]*val,
+      point[1]+normal[1]*val
+    ]);
+  }
+
+} else {
+  signature = signatureBase;
+}
+
+signature = [signature];
+
+bt.rotate(signature, bt.randInRange(
+      -signatureRotationRandomFactor, signatureRotationRandomFactor
+  ), bt.bounds(signature).cc
+);
+bt.translate(
+  signature,
+  [
+    width -15 + bt.randInRange(
+      -signaturePositionRandomFactor, signaturePositionRandomFactor),
+    15 + bt.randInRange(
+      -signaturePositionRandomFactor, signaturePositionRandomFactor)
+  ],
+  bt.bounds(signature).cc
+);
+bt.join(finalLines, signature);
+
+
+
+
+// draw it
+drawLines(finalLines);