Quickly Build a Frame-by-Frame Game - Beginning iOS6 Games Development - page 100

Geometric relations involved in the updateLocation task
5-5 , we see the X and the Y axis with the origin on the upper left and the positive Y axis
theta is calculated based on the values of
, dy , and the location of the move to point. The black arrow is of length speed and shows where
dxf and dyf are
calculated based on the angle.
Responding to a User Tap
We now know we can make the ship move, one frame at a time. But we have not looked at how we
tell the ship where to move. Recall that we registered a UITapGestureRecognizer on the root UIView
of Example01Controlller . This UITapGestureRecognizer is configured to call the task viewTapped: .
This is shown in Listing 5-6.
Listing 5-6. Example01Controller.m (viewTapped:)
-(void)viewTapped:(UIGestureRecognizer*)aGestureRecognizer{
UITapGestureRecognizer* tapRecognizer = (UITapGestureRecognizer*)aGestureRecognizer;
CGPoint tapPoint = [tapRecognizer locationInView:self.view];
[viper setMoveToPoint: tapPoint];
}