issue with view3D.dispose() #64
Description
I have an ObjectContainer3D OC1 that contains 2 other ObjectContainer3D OC2 and OC3 (containing each one a mesh).
If I add only OC1 as child to my view3D, calling the view3D.dispose() function make the program to crash with this error:
Null Object Reference
Called from openfl._legacy.display.Stage.__pollTimers (openfl/_legacy/display/Stage.hx line 1084)
Called from openfl._legacy.display.Stage.__checkRender (openfl/_legacy/display/Stage.hx line 351)
Called from openfl._legacy.display.Stage.__render (openfl/_legacy/display/Stage.hx line 1103)
Called from openfl._legacy.display.DisplayObjectContainer.__broadcast (openfl/_legacy/display/DisplayObjectContainer.hx line 286)
Called from openfl._legacy.display.DisplayObject.__broadcast (openfl/_legacy/display/DisplayObject.hx line 161)
Called from openfl._legacy.display.DisplayObject.__dispatchEvent (openfl/_legacy/display/DisplayObject.hx line 182)
Called from openfl._legacy.events.EventDispatcher.dispatchEvent (openfl/_legacy/events/EventDispatcher.hx line 98)
Called from flixel.FlxGame.onEnterFrame (flixel/FlxGame.hx line 523)
Called from flixel.FlxGame.step (flixel/FlxGame.hx line 681)
Called from flixel.FlxGame.update (flixel/FlxGame.hx line 701)
Called from flixel.FlxGame.switchState (flixel/FlxGame.hx line 608)
Called from gui.states.PlayState3D.destroy (gui/states/PlayState3D.hx line 289)
Called from away3d.containers.View3D.dispose (away3d/containers/View3D.hx line 1003)
Called from away3d.core.managers.Stage3DProxy.dispose (away3d/core/managers/Stage3DProxy.hx line 151)
Called from away3d.core.managers.Stage3DProxy.freeContext3D (away3d/core/managers/Stage3DProxy.hx line 492)
Called from openfl._legacy.events.EventDispatcher.dispatchEvent (openfl/_legacy/events/EventDispatcher.hx line 98)
Called from away3d.core.managers.AGALProgram3DCache.onContext3DDisposed (away3d/core/managers/AGALProgram3DCache.hx line 58)
Called from away3d.core.managers.AGALProgram3DCache.dispose (away3d/core/managers/AGALProgram3DCache.hx line 68)
Called from away3d.core.managers.AGALProgram3DCache.destroyProgram (away3d/core/managers/AGALProgram3DCache.hx line 115)
Called from openfl.display3D.Program3D.dispose (openfl/display3D/Program3D.hx line 25)
Called from openfl.display3D.Context3D.__deleteProgram (openfl/display3D/Context3D.hx line 229)
Now, If my ObjectContainer3D OC1 only contains 1 Mesh (instead of OC2 and OC3), there is no error. view3D.dispose() succed. The same thing if I I only put OC2 (with 1 mesh) as child of OC1 (so whithout OC3) and then put OC1 as single child of view3D (everything is fine in that case). The issue only appear if I have in my view3D an ObjectContainer3D with more than 1 child in it...