Partial re-renders

[ShaMan123]

@asturur @melchiar

The new group is maturing nicely. Thanks to that it is now possible to explore a few interesting directions.
Partial re-rendering. If we split up the canvas to 3X3 (or nXn) groups with objectCaching set to true we basically got it.
Related #7506 (reply in thread)

Layering is another, #7692 (comment)

Object batching is another but it is quite similar to partial re-rendering. A different name and a different need, but with group it's the same implementation.
Take a look at #7675

[asturur]

yes i want to work on partial re-renders since long, i hope i get to do it at some point.
I have an idea in mind i have to understand how performant is when you have to calculate object position/intersections in order to detect which objects do actually need to be redrawn.

The issue with the example of the 10.000 objects is that looping over 10.000 things to perform various checks, is already a show stopper for 60fps drawing ( of course redrawing just a couple of them would help )

[Ch1sKey]

The problem with collision intersections check is well known. The common solution is to use spacial data-structures, which speeds up search of the objects by coordinates. I see its quite challenging to embed such a structure to the current architecture. However potential performance gain should worth it.

[Ch1sKey]

As pointed here #8581, in theory, "partial re-renders" aka "advanced caching" aka "drawing by tiles" might be the only and most efficient way to scale fabric performance. The slowest part of rendering now is a render of each individual object, which would scale proportionally O(n) no matter how hard we try to optimise it.

[ShaMan123]

I disagree.
A simple example disproving it:
dragging an object across the canvas really quick.
You will need to invalidate all tiles...
It is a complex topic and I am not sure there is a single solution for all cases.
We have discussed exposing an interface for devs to do that themselves.

[Ch1sKey]

It's not necessary to invalidate all tiles while dragging but I see your point. There are multiple solutions for such problems with their own drawbacks.