From 0c35ad10a5f2a8b3e774b86fd48eeebe0165549c Mon Sep 17 00:00:00 2001
From: Daniel Shiffman <daniel@shiffman.net>
Date: Mon, 18 Mar 2013 21:56:23 -0400
Subject: [PATCH] some comments for the new morph example

---
 java/examples/Topics/Motion/Morph/Morph.pde | 48 +++++++++++++++++----
 1 file changed, 40 insertions(+), 8 deletions(-)

diff --git a/java/examples/Topics/Motion/Morph/Morph.pde b/java/examples/Topics/Motion/Morph/Morph.pde
index 1c6a65f81..e34fbad1b 100644
--- a/java/examples/Topics/Motion/Morph/Morph.pde
+++ b/java/examples/Topics/Motion/Morph/Morph.pde
@@ -5,32 +5,47 @@
  * vertices from one to another
  */
 
+// Two ArrayLists to store the vertices for two shapes
+// This example assumes that each shape will have the same
+// number of vertices, i.e. the size of each ArrayList will be the same
 ArrayList<PVector> circle = new ArrayList<PVector>();
 ArrayList<PVector> square = new ArrayList<PVector>();
 
+// An ArrayList for a third set of vertices, the ones we will be drawing
+// in the window
 ArrayList<PVector> morph = new ArrayList<PVector>();
 
+// This boolean variable will control if we are morphing to a circle or square
 boolean state = false;
 
 void setup() {
   size(640, 360);
 
+  // Create a circle using vectors pointing from center
   for (int angle = 0; angle < 360; angle += 9) {
+    // Note we are not starting from 0 in order to match the
+    // path of a circle.  
     PVector v = PVector.fromAngle(radians(angle-135));
     v.mult(100);
     circle.add(v);
+    // Let's fill out morph ArrayList with blank PVectors while we are at it
     morph.add(new PVector());
   }
 
+  // A square is a bunch of vertices along straight lines
+  // Top of square
   for (int x = -50; x < 50; x += 10) {
     square.add(new PVector(x, -50));
   }
+  // Right side
   for (int y = -50; y < 50; y += 10) {
     square.add(new PVector(50, y));
   }
+  // Bottom
   for (int x = 50; x > -50; x -= 10) {
     square.add(new PVector(x, 50));
   }
+  // Left side
   for (int y = 50; y > -50; y -= 10) {
     square.add(new PVector(-50, y));
   }
@@ -39,19 +54,36 @@ void setup() {
 void draw() {
   background(51);
 
+  // We will keep how far the vertices are from their target
+  float totalDistance = 0;
+  
+  // Look at each vertex
   for (int i = 0; i < circle.size(); i++) {
     PVector v1;
-    if (state) v1 = circle.get(i);
-    else v1 = square.get(i);
-    PVector v2 = morph.get(i);
-    v2.lerp(v1, 0.1);
-    float d = PVector.dist(v1, v2);
-    if (d < 0.01) {
-      state = !state;
+    // Are we lerping to the circle or square?
+    if (state) {
+      v1 = circle.get(i);
     }
+    else {
+      v1 = square.get(i);
+    }
+    // Get the vertex we will draw
+    PVector v2 = morph.get(i);
+    // Lerp to the target
+    v2.lerp(v1, 0.1);
+    // Check how far we are from target
+    totalDistance += PVector.dist(v1, v2);
   }
-
+  
+  // If all the vertices are close, switch shape
+  if (totalDistance < 0.1) {
+    state = !state;
+  }
+  
+  // Draw relative to center
   translate(width/2, height/2);
+  strokeWeight(4);
+  // Draw a polygon that makes up all the vertices
   beginShape();
   noFill();
   stroke(255);