Cubic bezier path tween for Sparrow framework 2.0+

gaurav.singh

Hi,

In one my project, it is needed to move a object along a path or curve. SPTween doesn't provide this functionality and SXMotionTween wasn't updated for use in Sparrow 2. I found a nice project called "BBCubicBezierPathTween" in sparrow forum which can tween a object along a curved path but was for Sparrow 1.4. I made some changes to the code and used that in my project. It worked brilliantly and was pretty smooth.

I have updated the code to some extent for sparrow framework 2.0 and uploaded it to a Github repository with a sample project at

https://github.com/gauravlnx/GSCubicBezierPathTween

Sample project contains the sparrow framework classes and can be executed as it is.
Original unedited project from Jon Beebe can be found at

https://github.com/somethingkindawierd/SparrowQuadBezier

Known issue:

There is a problem when repeatCount > 0 and reverse = YES due to which each of normal and reverse tween decrement the repeat count. In other words, for each animation loop w/ reverse enabled, repeat count must be assigned double the required value.

Shilo

Awesome, thank you for sharing!

xidadesign

Thanks! This sounds useful

seriousGeorge

Great, really sounds useful. Does it allow you to switch automatic rotation on/off?
Oh - and if someone would implement some thing of debug plotting to it, that would be awesome 🙂

BTW: I edited SXMotionTween in order to work with Sparrow 2.x. Just some minor changes and its working fine... I'm doing a lot of my enemy wave patterns with it.
http://forum.sparrow-framework.org/topic/tween-with-a-guide#post-17725

gaurav.singh

It does allow you to switch the automatic rotation on/off by toggling the boolean property "updateAngle" like:

bezTween.updateAngle = NO;

Previous to this, I was using SXMotionTween in my Sparrow 2.0 based project but observed some jerkiness to the end when animated in a loop. Instead I found this to be much smoother compared to SXMotionTween. Also there was no support for different transitions types in SXMotionTween

seriousGeorge

Thats great. And the debug drawing is just awesome. Will definitely integrate it right now in my project 😉

Thanks a lot!

Daniel

Awesome, thanks a lot for sharing, Gaurav!

gaurav.singh

Can anyone fix a issue in GSCubicBezierPathTween class which causes a normal tween w/ reverse enabled to use two repeat counts?

For example, if I need to animate a object w/ reverse 5 times, I have to set the repeat count to 10 (5 for normal tweening and 5 for reverse tweening).
It shouldn't be a problem if repeatCount is set as 0(infinite tweening).

The code in advanceTime: method is mostly similar the one in SPTween class because I have implemented it inside a copy of SPTween class from Sparrow framework v2.0 . So it shouldn't be difficult to fix but i am not too sure.

Currently I am busy working on a iOS project in my office and I am not able to devote the time needed to fix this issue. I also don't have MACs at my home (most probably in my locality also).

Any help will be appreciated. Thanks in advance

seriousGeorge

Hi Gaurav,

I do not have a solution for the reverse-double issue but I have a proposal for the repeat-values. I took me some time until I realized that a repeat count of 1 would stop the tween definitely (which I needed).

I suggest 0 should act for "No tween at all" and -1 for repeating indefinitely, as repeat 1 would do exactly as it reads... repeat 1 time additional to the original tween.

It's the same discussion the folks over at tweenmax (greensock.com) where into. They decided to put 0 for non-repeating and -1 for indefinitely repeating tweens. I think that's legit.

What do you think?

gaurav.singh

Hi serousGeorge,

Sorry for the late reply. I just want this class to behave similar to SPTween otherwise it may be confusing to developers when they use it in parallel to default tween class.
SPTween uses a repeat count of 0 for indefinite tweening and greater than 0 for definite.