Initial Commit

Java/Processing/processing-3.3.6/modes/java/examples/Topics/Interaction/Reach1/Reach1.pde

@@ -0,0 +1,50 @@
+/**
+ * Reach 1 
+ * based on code from Keith Peters.
+ * 
+ * The arm follows the position of the mouse by
+ * calculating the angles with atan2(). 
+ */
+
+ 
+float segLength = 80;
+float x, y, x2, y2;
+
+void setup() {
+  size(640, 360);
+  strokeWeight(20.0);
+  stroke(255, 100);
+  
+  x = width/2;
+  y = height/2;
+  x2 = x;
+  y2 = y;
+}
+
+void draw() {
+  background(0);
+  
+  float dx = mouseX - x;
+  float dy = mouseY - y;
+  float angle1 = atan2(dy, dx);  
+  
+  float tx = mouseX - cos(angle1) * segLength;
+  float ty = mouseY - sin(angle1) * segLength;
+  dx = tx - x2;
+  dy = ty - y2;
+  float angle2 = atan2(dy, dx);  
+  x = x2 + cos(angle2) * segLength;
+  y = y2 + sin(angle2) * segLength;
+  
+  segment(x, y, angle1); 
+  segment(x2, y2, angle2); 
+}
+
+void segment(float x, float y, float a) {
+  pushMatrix();
+  translate(x, y);
+  rotate(a);
+  line(0, 0, segLength, 0);
+  popMatrix();
+}
+