How to get position of sprite on visible rect

cocos2d-x C++
#1

Suppose I have sprite and i set its position randomly, how can determine sprite is visible on screen or not and if visible get relative location on screen.

I am asking this to make mario style follow.
Follower shouldn’t follow sprite when its on screen center-200 between screen center+200

I tried Follow::createWithOffset looks like doesnt work intended or I missing something.

for example
Follow::createWithOffset(sprite3, 200, 0, Rect(0,-3200, 4000, 800));

this works intended follows sprite at xOffset 200, if I only move player right to left its still follow player at same xOffset 200 point.

any suggestion about usage of createWithOffset?
thank you

#2

Are you using the API-Ref and the rest of our documentation? What about cpp-tests?

#3

I read API-Ref but didnt find actual implementation about this, only parameter explanations.

I checked cpp-test topics again but I didnt find any Follow related example.

after reading source (https://github.com/cocos2d/cocos2d-x/blob/v4/cocos/2d/CCAction.cpp) rect was world rect instead no-follow area so i changed my implementation but still doesnt work intended.

#4

Why aren’t you using setVisible and isVisible and checking the position to see if it’s on screen or off?

#5

looks like isVisible related to its hidden property instead location, I need to know sprite screen position x,y.

I made my approach its working but dont know it hurts performance, maybe best option is createWithOffset() but there is no documentation. :slightly_frowning_face:

#6

So getPosition()??

What you want to do is a few lines of code but you aren’t showing enough of what you are doing.

#7 
		auto sprite3nodeSpace = convertToNodeSpace(sprite3->getPosition());
	
		if( sprite3nodeSpace.x > *lastFollowpos + *offsetsize){
			*lastFollowpos = sprite3nodeSpace.x - *offsetsize;
			if(numberOfRunningActions()==0){
				sprite3action = Follow::createWithOffset(sprite3, *offsetsize, 300, Rect(0,0, 5200, 800));
				followTheSprite = this->runAction(sprite3action);	
			}	
		}
		
		if( sprite3nodeSpace.x < *lastFollowpos - *offsetsize){
			*lastFollowpos = sprite3nodeSpace.x + *offsetsize;
			if(numberOfRunningActions()==0){
				sprite3action = Follow::createWithOffset(sprite3, -*offsetsize, 300, Rect(0,0, 5200, 800));
				followTheSprite = this->runAction(sprite3action);	
			}
		}
		
		if( (sprite3nodeSpace.x > *lastFollowpos - *offsetsize ) && (sprite3nodeSpace.x < *lastFollowpos + *offsetsize) ){
			this->stopAction(followTheSprite);
		}

this is working in schedule at 0.01f , I used createWithOffset based on low and high limit, but maybe some one know better approach

#8

Why not use getPosition().x , getPosition().y?

#9

I used getPosition and i can check sprite on screen position as above code but dont know this is best approach because createWithOffset made for this issue as I read in this post : Follow action cocos2d-x v3.2. Why always centered followed?

#10

I check all the time for on and off screen.

#11

I think createWithOffset should accept another rect parameter for no-follow zone

#12

auto pos = sprite->getParent()->convertToWorldSpace(sprite->getPosition());

#13

@hoisung thank you

#14

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