Use scrollRect to clip filters and position game window

[Geokureli]

Fixes #2258

Adds a scrollRect to the game to ensure that game filters are the expected size. Also adds public filteredContainer, inputContainer and cameraContainer fields to FlxGame while deprecating the old private _inputContainer field. This is both to show the debugger above the game filters and organize things better so that the dev can simply add filters to FlxG.game.cameraContainer directly.

I tested this with the ScaleModes demo and it seems to work for every mode.

TODO: figure out why resizing the window messes this up even though the rect values are as expected

[Geokureli]

@ACrazyTown originally I wasn't going to add the new containers, but this didn't work without it, specifically with FixedScaleMode, which cut off the debugger, because it's positioned at a negative x/y.

[ACrazyTown]

Not sure what you meant by "figure out why resizing the window messes this up" but when testing this, I noticed that the sound tray and mouse were offset. Replacing this block with:

FlxG.game.x = offset.x;
FlxG.game.y = offset.y;

final rect = FlxG.game.filteredContainer.scrollRect;
rect.setTo(0, 0, gameSize.x, gameSize.y);
FlxG.game.filteredContainer.scrollRect = rect;

seemed to fix things for me.

[Geokureli]

Not sure what you meant by "figure out why resizing the window messes this up" but when testing this, I noticed that the sound tray and mouse were offset.

If the window is manually resized via dragging, the error observed in #2258 happens. It's very apparent in Ratio (screenFill) Mode of the scalemodes demo. I'm using Filipp8's border shader to keep track of the screen size. This also happens in release mode so I don't think it's the debugger.

This happens even with your changes

Full example here: https://gist.github.com/Geokureli/eac8544261befb05cb36182676f8fb60

Edit: I noticed in my issue, above, if you disable filters and then re-enable filters - via FlxG.game.filtersEnabled - the issue is corrected. I also notice the issue happens when switching to different modes, it's also corrected when toggling filters on and off.

[ACrazyTown]

Edit: I noticed in my issue, above, if you disable filters and then re-enable filters - via FlxG.game.filtersEnabled - the issue is corrected. I also notice the issue happens when switching to different modes, it's also corrected when toggling filters on and off.

That sounds oddly similar to #2258 (comment). I wonder if my camera shader fix in OpenFL (openfl/openfl#2797) would also fix this?

[Geokureli]

I'll try it out