/*
	This is our utility function for drawing overlays
	describing the force vectors acting on our object.
*/
void drawOverlay(Vector2D v, Vector2D location, float tscale, String name) {

  if (showVectors == true) {
	// save our drawing environment
	pushMatrix();
	
	// move to our position to draw our force vector
	translate(location.getX(), location.getY());

	// drawing settings
	stroke(255);
	float arrowSize = 10;
	float arrowLength = v.magnitude() * tscale;
	
	// rotate so that the direction of our drawing is the heading
	// of our vector
	rotate(v.heading());
	
	// draw the arrow
	line(0, 0, arrowLength, 0);
	line(arrowLength, 0, arrowLength - arrowSize, arrowSize / 2);
	line(arrowLength, 0, arrowLength - arrowSize, arrowSize / 2 * -1);
	
	// label our arrow
        fill(255, 255, 255, 255);
	text(name, arrowLength, 0);

	// reset our drawing environment
	popMatrix();
  }
}