DragHandler erroneous starting offset

There is a bug in the DragHandler class. The

basePotition = capture.getWorldTranslation().clone()

line in startDrag() should probably instead be

basePosition = capture.getLocalTranslation().clone()

because everywhere else the handler is working with the local translation and getting the world translation here introduces an abnormal initial offset on drag start if the spatial is a child of some other spatial and its relative location is not 0, 0, 0.

It is easy to demonstrate this behavior by modifying the com.simsilica.lemur.demo.BasicDemo class: replace the line

guiNode.attachChild( testPanel );

in simpleInitApp() with

Node node = new Node();
node.attachChild(testPanel);
node.setLocalTranslation(200, 200, 0);
guiNode.attachChild(node);

and try to drag the testPanel.

[pspeed42]

Fix committed and confirmed it works in the demo. Closing this issue.

[pspeed42]

I don’t think it requires all that. I haven’t tested it or anything but I believe it’s as simple as: -continue calculating dragging in world space as before -instead of calling spatial.setLocalTranslation() with the world space coordinate, convert that world space coordinate to local space with spatial.getParent().worldToLocal()