How would I do child > parent relative rotation without using a container?

[visgotti]

https://jsfiddle.net/2hb18pzg/1/

 

In that fiddle I want the green rectangle sprite to always be in the top right corner of the parent as they rotate. I know I can solve this by using a parent container but I want to do this without a container, I know it's something to do with setting the child's anchor and pivot correctly relative to the parent, but I can not for the life of me figure out how to do it properly.

[wes101620]

Maybe this is a solution you're looking for. Updating child x coordinate to match the parent in your loop.

setInterval(() => {
  parentRect.rotation += .5;
  childRect.rotation += .5;
  childRect.x = parentRect.x;
    renderer.render(mainStage);
}, 100)
 

[jonforum]

Am sure you will not keep your variable hard coded like this , but basic math operations from rotations should do the jobs !

 childRect.rotation = -newRotation/newRotation-0.5;

for this demo is work, in a complexe case you will need make more solide math algo.