touchBegan timestamp - iphone

Question

In my game I need to calculate duration of touch. I did this by :
-(BOOL) ccTouchBegan:(UITouch *)touch withEvent:(UIEvent *)event {
self.endTime = [NSDate date]; //NSDate *endTime in .h
NSLog(#"%#",self.endTime);
}
-(void) ccTouchEnded:(UITouch *)touch withEvent:(UIEvent *)event
{
tStart = [[NSDate date] timeIntervalSinceDate:self.endTime];
NSLog(#"duration %f",tStart);
I am using this time interval as a factor to calculate height of the jump the player makes.
Less is the tStart, low is the jump and more is the tStart, high is the jump. I am doing this as :
if(tStart/1000<=9.430)
{
[player jump:5.0f];
}
else if(tStart>9.430 && tStart<=9.470)
{
[player jump:7.0f];
}
else if(tStart/1000>9.470)
{
[player jump:8.0f];
}
However I want to perform this action on tochBegan so that player may jump as soon as screen is touched. For this need the value of tStart in touchBegan. How should I do that?
Thanks

Answer 1

For a given touch, the UITouch instance is the same, so at ccTouchBegan save the touch/touches with the oldest timestamp and then wait for ccTouchEnded. When you get the UITouch that you previously saved, it means the player lifted the finger.
update
You can
Jump as soon as the user touches the screen.
Jump and boost the jump while the touch is ongoing up to x milliseconds (suggestion from grapefrukt).
Jump when the user releases the touch or a max time of x milliseconds has elapsed.
Jump and boost the jump until the touch is over.
Option 4 is unpractical because the user can keep pressing as long as he wants. So given that you want to make a variable jump, here is code for option 3:
UITouch *jump = nil;
-(BOOL) ccTouchBegan:(UITouch *)touch withEvent:(UIEvent *)event {
// no jump ongoing, start one
if (jump==nil){
jump = touch;
// jump on a separate thread
[NSThread performSelectorInBackground:(SEL)jump withObject:touch];
}
}
-(void) jump:(UITouch*) touch {
NSInterval time = [touch timestamp]; // I *think* this is the time since system uptime :P
int jumpSpeed = 1;
// increase the jump speed for every 100ms up to 'maxTimeYouAreAllowedToJump' ms
while ( ([NSProcessInfo systemUptime]-time < maxTimeYouAreAllowedToJump) && (jump!=nil) ){
jumpSpeed += 1;
[NSThread sleepForTimeInterval:.1]; // sleep for 100ms
}
[self doTheJumpingWithSpeed:jumpSpeed]; // do the actual jump!
}
-(void) ccTouchEnded:(UITouch *)touch withEvent:(UIEvent *)event {
// user released the touch that initiated the jump
if ((touch!=nil) && (touch==jump)) {
jump =nil;
}
}