Quick snippet for actioning touches by touch down index, i.e. in sequence

indexed_touches_snippet.m

// DNF: @implementation { NSMutableArray *_activeTouches }

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    for (UITouch *t in touches) {
        NSUInteger idx = _activeTouches.count;
        [_activeTouches addObject:t];
        [self _updateForTouch:t withIndex:idx];
    }
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
    for (UITouch *t in touches) {
        NSUInteger idx = [_activeTouches indexOfObject:t];
        [self _updateForTouch:t withIndex:idx];
    }
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    [_activeTouches removeObjectsInArray:touches.allObjects];
}

- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
{
    [_activeTouches removeObjectsInArray:touches.allObjects];
}


- (void)_updateForTouch:(UITouch *)touch withIndex:(NSUInteger)touchIdx
{
  // ...
}