Sparrow Forum

1. 

   straydogstrut
   Administrator

   Evening all,

   I created a generic method to handle execute tweens for lots of objects, rather than having to write out all the tween code each time. This has worked fine for weeks but i'm not using this everywhere in my game yet so there may be issues I haven't run into.

   -(void) animateObject:(SPDisplayObject*)targetObj property:(NSString *)pstring targetLoc:(int)tvalue duration:(float)time tweenType:(NSString*)transition
   {
   	[self.stage.juggler removeTweensWithTarget:targetObj];
   	SPTween *myTween = [SPTween tweenWithTarget:targetObj time:time transition:transition];
   	[myTween animateProperty:pstring targetValue:tvalue];
   	[self.stage.juggler addObject:myTween];
    
   }

   Using this I can call, for example:

   [self animateObject:mainMenuSpider property:@"y" targetLoc:220 duration:2.0f tweenType:SP_TRANSITION_EASE_OUT_BOUNCE];

   I am now finding that I need to be able to chain tweens or atleast know when the tween has finished.

   I didn't want use TWEEN_COMPLETED methods as i'm not sure how I would get a message back to the method that calls it that the tween has completed when I may not be aware of the tween at that level. I suppose I could bubble up a message but i'm trying to keep this contained in a single method (I might move it to it's own class if it needs to be any more complex). So instead I tried passing a delay parameter, however this crashes with an invalidException:

    
   -(void) animateObject:(SPDisplayObject*)targetObj property:(NSString *)pstring targetLoc:(int)tvalue duration:(float)time tweenType:(NSString*)transition tweenDelay:(float)delay
   {
   	[self.stage.juggler removeTweensWithTarget:targetObj];
   	SPTween *myTween = [SPTween tweenWithTarget:targetObj time:time transition:transition];
           myTween.delay = delay;
   	[myTween animateProperty:pstring targetValue:tvalue];
   	[self.stage.juggler addObject:myTween];
    
   }

   I'm not sure why, however I would like to know if this kind of approach is even possible? Thanks

   Posted 9 months ago #
2. 

   borrrden
   Moderator

   The "atObject" property of the "addEventListener" is the object where the method will be called upon completion, as far as I know (it is a bit awkwardly worded, as it suggests that is it the object which will be the target of the event). So as long as you have a reference to the object where the method is defined, you will be fine. How are you going to handle chaining in such a generic event though? What if you want to make a chain of 3? I think you are better off just making the function return the tween, then adding it yourself in the main part if you want to do that.

   Posted 9 months ago #
3. 

   straydogstrut
   Administrator

   Returning the tween makes a lot of sense. I tried that and got it working with adding the .delay outside my animateObject() function after the tween is returned. I then moved it inside the function, still returning the tween and adding it to the juggler outside the function. It works, but I found that I have to call the function and the add to stage in a specific order to get it to work.

   This works:

   SPTween *horizontalTween = [self animateObject:mainMenuSpider property:@"x" targetLoc:audioButton.x duration:1.0 tweenType:SP_TRANSITION_LINEAR tweenDelay:0 tweenLoopType:nil];
   SPTween *verticalTweenDown = [self animateObject:mainMenuSpider property:@"y" targetLoc:audioButton.y duration:1.0 tweenType:SP_TRANSITION_EASE_OUT_BOUNCE tweenDelay:horizontalTween.time tweenLoopType:nil];
    
   [self.stage.juggler addObject:horizontalTween];
   [self.stage.juggler addObject:verticalTweenDown];

   But this only plays the second tween?

   SPTween *horizontalTween = [self animateObject:mainMenuSpider property:@"x" targetLoc:audioButton.x duration:1.0 tweenType:SP_TRANSITION_LINEAR tweenDelay:0 tweenLoopType:nil];
   [self.stage.juggler addObject:horizontalTween];
    
   SPTween *verticalTweenDown = [self animateObject:mainMenuSpider property:@"y" targetLoc:audioButton.y duration:1.0 tweenType:SP_TRANSITION_EASE_OUT_BOUNCE tweenDelay:horizontalTween.time tweenLoopType:nil];
   [self.stage.juggler addObject:verticalTweenDown];

   I've also run into the problem you mentioned: not being able to queue more than two tweens. Doing this, the third tween doesn't play, sometimes the second also (NSLogging this out shows the animateObject method is called 3 times):

   SPTween *horizontalTween = [self animateObject:mainMenuSpider property:@"x" targetLoc:audioButton.x duration:1.0 tweenType:SP_TRANSITION_LINEAR tweenDelay:0 tweenLoopType:nil];
   SPTween *verticalTweenDown = [self animateObject:mainMenuSpider property:@"y" targetLoc:audioButton.y duration:1.0 tweenType:SP_TRANSITION_EASE_OUT_BOUNCE tweenDelay:horizontalTween.time tweenLoopType:nil];
   SPTween *verticalTweenUp = [self animateObject:mainMenuSpider property:@"y" targetLoc:20 duration:1.0 tweenType:SP_TRANSITION_LINEAR tweenDelay:verticalTweenDown.time tweenLoopType:nil];
    
   [self.stage.juggler addObject:horizontalTween];
   [self.stage.juggler addObject:verticalTweenDown];
   [self.stage.juggler addObject:verticalTweenUp];

   --

   On another note, I tried to further cram my animateObject method with functionality by adding a loop parameter. My intention was to pass in SPLoopTypeReverse etc and you can see this above. I tried using an NSString as this worked for the transition, but with the loop it fails with 'incompatible type' when trying to assign it to the loop property:

   myTween.loop = loopType;

   I also tried passing the type as SPLoopType as shown above but this also fails with the same error, even if I force it:

   myTween.loop = (SPLoopType*)loopType;

   It's not often I look at the Sparrow source code but it seems to be an SPLoopType in there so I don't understand it? Also why does this fail but the transition can be passed as a string?

   Thanks

   Posted 9 months ago #
4. 

   borrrden
   Moderator

   I'm not sure about the first problem (that code looks like it would work either way to me), but I can help with the others. SPLoopType is an enum, not a string, so it's really a number (and it's not a pointer either). You can find it at the top of SPTween.h. You must pass it literally, not as a string (enum has no idea what a String is). SP_TRANSITION_?, on the other hand, IS a string, you can find them #defined at the top of SPTransitions.h.

   Also, the reason why your stacking of 3 is not working is that you are sending the incorrect time for the 3rd one. You want it to run after the first two right? Then you must delay it by the time of the FIRST AND THE SECOND (first.time + second.time). You are only delaying it by the second.

   Posted 9 months ago #
5. 

   Jugibur
   Moderator

   Hi straydogstrut,

   as borrrden said, the property "time" doesn't contain the delay of each tween, otherwise you could use the overall time of the last tween.

   But you can easy extend SPTween with a category for a "overallTime" or "totalTime"
   So you doesn't have to write "prevTween.time + prevTime.delay"

   // SPTween+Ext.h
    
   @interface SPTween (SPTween_Ext)
    
   @property (nonatomic, readonly, getter=getTotalTime) double totalTime;
    
   @end

   // SPTween+Ext.m
    
   @implementation SPTween (SPTween_Ext)
    
   - (double)getTotalTime
   {
       return self.time + self.delay;
   }
    
   @end

   Another approach to handle a chain of tweens is to build an manager object which holds all tweens for a period (as array). The chain could be started through this manager, which is the listener for "TweenEnded". And after this event has sent, this manager adds the next tween to the juggler.
   So you can have a really long chain of tweens without the hassle to add delays and times of each predecessor.

   Posted 9 months ago #
6. 

   straydogstrut
   Administrator

   ..the reason why your stacking of 3 is not working is [...] you must delay it by the time of the FIRST AND THE SECOND
   

   I completely missed that. I've only had to deal with a couple of tweens up until now, I didn't stop to think about what the delay was actually doing=S
   
   SPLoopType is an enum, not a string
   
   I see, no wonder I couldn't get it to work. I'm going to look into enums further as I haven't used them before and i've found what i've read so far a little baffling to be honest. I've dropped the loop parameter for now as I don't really need it for the time being.

   I've got it working. I will move some of this code out into another class like the MsgBox example in the docs as i'm repeating the same code for every button right now which is terribly bad, I know=S

   I still seem to have to add my tweens to the juggler after setting them all up otherwise the IF statement i'm trying to use doesn't work. Also, I believe I ran into the issue of comparing floats that i've read about so using similar code to my collision check seems the only way around it (although I don't need the y property!):

   -(void) onAudioButtonTriggered:(SPButton *)button
   {
   	float delay = 0.0f;
   	SPTween *horizontalTween = nil;
    
   	SPPoint *p1 = [SPPoint pointWithX:mainMenuSpider.x y:mainMenuSpider.y];
   	SPPoint *p2 = [SPPoint pointWithX:audioButton.x y:mainMenuSpider.y];
    
   	float distance = [SPPoint distanceFromPoint:p1 toPoint:p2];
   	NSLog(@"distance: %f",distance);
   	if(distance > 10){
    
   		horizontalTween = [self animateObject:mainMenuSpider property:@"x" targetLoc:audioButton.x duration:1.0 tweenType:SP_TRANSITION_LINEAR tweenDelay:0];
   		delay = horizontalTween.time;
   	}
    
   	SPTween *verticalTweenDown = [self animateObject:mainMenuSpider property:@"y" targetLoc:audioButton.y duration:1.0 tweenType:SP_TRANSITION_EASE_OUT_BOUNCE tweenDelay:delay];
   	delay += verticalTweenDown.time;
    
   	SPTween *verticalTweenUp = [self animateObject:mainMenuSpider property:@"y" targetLoc:20 duration:1.0 tweenType:SP_TRANSITION_LINEAR tweenDelay:delay];
   	//delay += verticalTweenUp.time;
    
   	[self.stage.juggler addObject:horizontalTween];
   	[self.stage.juggler addObject:verticalTweenDown];
   	[self.stage.juggler addObject:verticalTweenUp];
   }

   Jugibur, I like your suggestions a lot. I've manually added up the delay for now but extending the tween class is very attractive. I'll have to have a think about the implementation of a tween manager - actually i'm not sure it will be necessary for this project as the three tweens above are the most needed at once in the project - but i'm tempted to give it a go just for my own amusement=)

   Thank you both, you've been extremely helpful!

   Posted 9 months ago #

RSS feed for this topic

Reply

You must log in to post.