moving vector examples to Topics

java/examples/Topics/Vectors/VectorMath/VectorMath.pde

@@ -0,0 +1,37 @@
+/**
+ * Vector 
+ * by Daniel Shiffman.  
+ * 
+ * Demonstration some basic vector math: subtraction, normalization, scaling
+ * Normalizing a vector sets its length to 1.
+ */
+
+void setup() {
+  size(640,360);
+  smooth();
+}
+
+void draw() {
+  background(0);
+  
+  // A vector that points to the mouse location
+  PVector mouse = new PVector(mouseX,mouseY);
+  // A vector that points to the center of the window
+  PVector center = new PVector(width/2,height/2);
+  // Subtract center from mouse which results in a vector that points from center to mouse
+  mouse.sub(center);
+  
+  // Normalize the vector
+  mouse.normalize();
+  
+  // Multiply its length by 150 (Scaling its length)
+  mouse.mult(150);
+
+  translate(width/2,height/2);
+  // Draw the resulting vector
+  stroke(255);
+  line(0,0,mouse.x,mouse.y);
+  
+}
+
+