cocos2d for iPhone

A fast, easy to use, free, and community supported 2D game engine

1. 

   xlc
   Member

   I want to move a node and call a block after move done. But sometimes I need to move the node to another position while that node is moving (change destination).
   I can't simply stop the previous action and start new one because than the callback will not be called and lead to inconsistent state.

   
id move = [CCMoveTo actionWithDuration:time position:pos];
id call = [CCCallBlock actionWithBlock:^{
// do something like clean up
}];
CCSequence *action = [CCSequence actions:move, call, nil];
action.tag = kMovingActionTag;
[node runAction:action];


   I can get the action by CCSequence *action = (id)[node getActionByTag:kMovingActionTag]; but than the only thing I can do is stop it and lost the CCCallBlock action.

   Posted 4 months ago #
2. 

   mrdckx
   Member

   "I can't simply stop the previous action and start new one because than the callback will not be called and lead to inconsistent state."

   Just make sure the new action has the callback in the sequence to..

   Posted 4 months ago #
3. 

   xlc
   Member

   But how do I get the callback action/callback block from sequence action? The block used some __block variable so I can't simply recreate one.

   Posted 4 months ago #
4. 

   indy2005
   Member

   Is there a way to just update a property over the course of an action, then you could perhaps adjust the property outside the action? Need something like this myself.

   Posted 4 months ago #
5. 

   araker
   Moderator

   CCMoveTo uses a start position and a delta, so setting the position won't do any good.

   @xlc, if you retain the CCCallBlock in a property, you can use it again in another sequence. Don't forget to release the property afterwards.

   At the moment it's just not possible to adjust actions on the fly.

   Posted 4 months ago #
6. 

   xlc
   Member

   This is the solution I came out with.

   @interface CCMoveTo (MAddition)

   - (void)setEndPosition:(CGPoint)position;

   @end

   @interface CCFiniteTimeAction (MAddition)

   - (CCFiniteTimeAction *)getActionByTag:(NSInteger)tag;

   @end

   @implementation CCMoveTo (MAddition)

   - (void)setEndPosition:(CGPoint)position {
   CGPoint pos = [target_ position];
   CGFloat dis = ccpLength(delta_);
   CGFloat move = ccpDistance(endPosition_, pos);
   CGFloat percent = move / dis;

   endPosition_ = position;
   delta_ = ccpSub( endPosition_, pos);
   delta_.x /= percent;
   delta_.y /= percent;
   startPosition_ = ccpSub(endPosition_, delta_);
   }

   @end

   @implementation CCFiniteTimeAction (MAddition)

   - (CCFiniteTimeAction *)getActionByTag:(NSInteger)tag {
   return self.tag == tag ? self : nil;
   }

   @end

   @implementation CCSequence (MAddition)

   - (CCFiniteTimeAction *)getActionByTag:(NSInteger)tag {
   CCFiniteTimeAction *action = [actions_[1] getActionByTag:tag];
   if (!action) {
   action = [actions_[0] getActionByTag:tag];
   }
   return action;
   }

   @end

   and can use like this

   CCSprite *node = [CCSprite spriteWithFile:<#(NSString *)#>];
   [self addChild:node];

   id move = [CCMoveTo actionWithDuration:5 position:ccp(768, 1024)];
   [move setTag:2];
   id call = [CCCallBlock actionWithBlock:^{
   NSLog(@"Done");
   }];
   id action = [CCSequence actions:move, call, nil];
   [action setTag:3];
   [node runAction:action];
   [scheduler_ scheduleAfterDelay:2 block:^(ccTime dt) {
   id sequence = [node getActionByTag:3];
   id move = [sequence getActionByTag:2];
   [move setEndPosition:ccp(0, 1024)];
   }];

   Posted 4 months ago #

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