Emscripten: Rework touch input and add pixel-perfect scaling

[johannschopplich]

This PR brings a batch of web-shell improvements over from my production setup on realtroll.de. Mostly touch and scaling work that's been running there a while – figured it's worth upstreaming rather than sitting in a fork. 🙂

What's New?

• Touch controls – rewritten on modern browser's Pointer Events. The on-screen controls are now a responsive grid (d-pad / screen / action buttons) with safe-area insets, both orientations, in place of the floating corner buttons.
• Pixel-perfect scaling – optional toggle that snaps the canvas to whole multiples of 320×240 (letterboxed), persisted in localStorage. Defaults on for non-touch devices – a visible change for existing desktop pages, so happy to flip it to opt-in if you'd rather not move the default.
• Save manager – download any slot as a backup, import a .lsd save file into the first free slot, and grab a screenshot. Built on a native <dialog>, touch-friendly.

Smaller bits

• Touch controls dim when idle, light back up on input. Great for cut scenes!
• Wake Lock re-acquired on visibilitychange so the screen doesn't sleep mid-session.
• Fullscreen button now toggles enter/exit and reflects its state (still hides if unsupported, iOS Safari).
• Dropped the legacy scanGamePads poll – it only armed when ongamepadconnected was missing, but those events predate WASM in every browser, so nothing that can run the player reached that path.
• UI icons consolidated into one inline SVG sprite (<symbol> / <use>).

The embedded player should work as is, integer scaling is of course disabled in this case.

Tested on past + edge releases of the EasyRPG Player build I ship at realtroll.de, desktop + touch (Android/iOS).

[Ghabry]

Jenkins: Test this please

Thanks! Have to take a look at this :)

[johannschopplich]

Pushed a follow-up batch from the same setup: a save manager! Fits nicely into the design.

Updated the description above accordingly. 🙂

[jetrotal]

Hello, since you are working on the touch screen buttons for the weblpayer, maybe consider taking a look at this proposal from a user called Bilou Master Joke: https://codepen.io/editor/BilouMaster/pen/019edf09-20e1-73a0-8efa-3ccb9a832518

He made a bunch of suggestions to both support the complete vanilla keyboard, and some quality of life usage of buttons.

[johannschopplich]

@jetrotal Thanks for the input! Honestly, it feels a bit rough, but it's a draft anyway. Worth digging into for a future iteration after this PR. (It already touches a lot of parts of the shell.)

[BilouMaster]

Ah yes, that's perfect because I've been doing the design only like an empty shell and not finished/merged with the real player yet, so I'll also take inspiration of your work then! :D

You can check the codepen Jetrotal shared (most recent take) or my old previous player which had better layout too but not commutable/customisable yet
https://biloumaster.fr/jeux/bogossstory

I like your buttons for importing save files or toggle between perfect pixel/not perfect, that's a good point but they are small and too close to each other, it would likely need a bit scale up + more margin but 👍

[johannschopplich]

@BilouMaster Love the input. 🙏 Yeah sure! Maybe we can collaborate on the implementation. My take: Giving users too much customization options clutters interfaces. I prefer a unified polished interface in general. But that's personal preference, eh.

On the buttons – good catch. The icon controls had too little spacing between them (due to my buttons control unification in this PR). I've improved every tap target and given the control row more room.

[BilouMaster]

The customisation costs nothing and I'm planning to set the perfect ratio by default so the customisation will just be a fallback for accessibility and non anticipated cases like non conventional devices, I feel it's safer to add some free settings beside the way we think it's good.

The swap Enter/Echap have been demanded many times for example

Sure we can collaborate on this, I will clone your branch (or the merged in official if the pr is accepted) when I'll have time to re-work on this, I've had many other things to do lastly :)

Let's build the perfect controller together, this big beauty of a project needs it :D