TurboWarp
[BUG] If there is no sprite to drag, TurboWarp keeps checking on every mouse move
On the stage, if user presses mouse button down where there are no draggable sprites, and then starts moving the mouse while still holding the button pressed, on every mouse move TurboWarp will keep checking whether there is anything at the position of the original press. The moment some sprite comes into the contact with that position, that sprite will become dragged and will teleport to the mouse.
https://github.com/user-attachments/assets/a1dfc95c-aade-4a58-8444-6b4101f71417
While the direct consequences of the bug are minor, the main problem caused by it is actually performance. While doing it, it ends up calling pick(x, y), which runs for a single pixel on the CPU and requires silhouettes. For that it ends up calling unlazy() on every visible skin. Some extensions (e.g. Simple3D) add large dynamic skins, for which calling gl.readPixels can noticeably degrade performance.
Here is a screenshot that demonstrates console.log(new Error("unlazy")) being inserted to run every time unlazy() is called. The first part is the mouse down, the 1240 calls at the middle part are mouse move amd the last part is mouse up.
This doesn't happen to Pen layer, because it is excluded from pick(x, y):
i was going to fix the performance by making all the pick() places only consider drawables corresponding to targets but I forgot text bubbles exist and are intended to block clicking on what's below so this will be a bit more annoying than a simple one line patch but it will be fixed soon
Probably I will add an attribute like excludeFromPick or interactive to Drawable which will exclude it from pick() by default
The private field is already a reasonably similar idea
I do not understand like the more technical parts of this problem but it pretty much makes 3D mobile games impossible no matter how much u optimise the game
pick() is still being called more than it should, but pick() now ignores the Simple 3D drawable (and any other drawable marked non-interactive), so the performance impact should be fixed