TLeaf

• addChild:
• addParent:
• isStatic
• setStatic:
• valid
• valid:

• createPrimitive:
• destroyPrimitive:
• invalidate:

• initialize

"When we add a new primitive to this object, we need to add all of it's component primitive objects to ensure that their frameNumber is properly updated when we use this. Further, we need to tell the child primitives that they are being used somewhere else so that when they are invalidated, they can invalidate the entire tree."
	childPrimitives add: prim.
	prim addParent: self.

"see #addChild: comment."
	parentPrimitives add: parent.

	
	^ isStatic.

	
	isStatic _ static.

	^ valid.

	valid _ bool.

" override this method to specify how the object should be constructed."

	
"override this method for destroying the object"

"This can only attempt to invalidate this object - if it is being used by a parent ogl object, this will fail because the current object is still in use somewhere. We return false if the invalidate failed, true if it succeeded."
	| pprims |
	valid ifFalse:[ ^true.].
	ogl timeStamp = timeStamp ifTrue:[ ^ false]. "we just used this, and probably will again soon"
	pprims _ parentPrimitives copy.
"test to see if we have just used a parent that used this, so we can't remove."
	pprims do:[:pp | (pp invalidate: ogl) ifFalse:[^ false] ifTrue:[parentPrimitives remove:pp]]. 
"nobody cares, or we were able to invalidate all of the parents, so let's remove ourselves from the children. We don't invalidate the children because they could still be useful, and unlike the parents, the children do not depend upon us."
	childPrimitives do:[:cp | cp removeParent: self].
	self destroyPrimitive: ogl.
	valid _ false.
	^ true.	

	super initialize.
	childPrimitives _ OrderedCollection new.
	parentPrimitives _ OrderedCollection new.
	timeStamp _ 0.
	valid _ false.
	isStatic _ true.