Question

I have created a basic GLKit application in Objective C (using Xcode), using a barebones setup I got from here: http://games.ianterrell.com/2d-game-engine-tutorial/ .
I want to make my application interactive, by receiving touch data from the screen.

I don’t have an xib file, and from my limited understanding of this, I have to somehow create a UIView, hook it up to everything I’ve already created, then possibly overload the touches began function (getting the input in a UITouch object, then passing it around the application).

Does anyone know how this can be done?

Answer 1

You need to look into gesture recognizers, please check out the documentation for UIGestureRecognizer: http://developer.apple.com/library/ios/#documentation/UIKit/Reference/UIGestureRecognizer_Class/Reference/Reference.html

This example can be used for a pinch gesture on your view:

UIView *myView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 400)];
// setup and add the view.

UIPinchGestureRecognizer *pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self 
                                                                                   action:@selector(handlePinch:)];

[myView addGestureRecognizer:pinchGesture];

Now you must implement a method called handlePinch: (this is you who defines what this method is called), you define this method as follows:

-(void)handlePinch:(UIPinchGestureRecognizer*)gesture {
    // do what you want, all info about the pinch is in the gesture
}

Other gestures you can use like this “out of the box” are:

UITapGestureRecognizer
UIPinchGestureRecognizer
UIRotationGestureRecognizer
UISwipeGestureRecognizer
UIPanGestureRecognizer
UILongPressGestureRecognizer