Update SDL3, bringing in support for Windows Ink pen input, and enable it on desktop platforms once again

[Susko3]

• Supersedes Fix touch input cancellation no longer being handled in latest SDL #6484
• Closes Media Buttons no longer working osu#28254
• Closes Fixing windows ink tablet events on SDL3 #6291
• Closes SDL3: tablet driver bug with a new lazer update osu#28223
• Closes SDL3: Tablet hovering impossible without turning on "Tablet" option in input settings. osu#30641
• Resolves the soft dependency for Add input type for decimal numbers #6498 (comment)

---

Depends on:

• Update SDL3 bindings for Windows Ink support SDL3-CS#197
• Update native binaries SDL3-CS#200
• SDL3-CS release

This PR will make SDL3 the default option, see ppy/osu#30641 (comment). OSU_SDL3=0 can be set to use SDL2.

---

Issues to check after this SDL3 update propagates to osu!:

• SDL3: The new screen modes are unusable on macOS osu#28222
• SDL3: Windows cursor shows in game (not the in-game cursor) osu#28279
• SDL3: Screen mode changes causing visual issues, a crash and a monitor disconnect on Linux osu#28259

[frenzibyte]

I was going to come here to mention that I've only deprioritised and no longer looked at ppy/osu#28222 as we still reverted back to using SDL2, but now that it is being enabled back again in this PR, I've went back and tested to see how fullscreen is behaving currently. I was glad to see that apparently I cannot reproduce the yabai issue anymore, so then I wanted to confirm that on SDL's test projects but somehow I still encountered it there.

I don't feel interested enough to care about why that happened but I'm giving this PR an i-dont-care approval from me with regards to having SDL3 enabled on macOS. If I get bothered enough, I'll report it out loud.

[Walavouchey]

used susko's instructions to test the newer sdl3 binary with frenzi's pr + this pr's sdl hints, and it does allow touch tapping with pen aim (with noticeably more latency than regular touch aim and tapping), but it breaks hover input completely (can only drag) (logs if ya need 'em)

also summons the touch device mod when using the pen, which isn't quite expected either

[Susko3]

used susko's instructions to test the newer sdl3 binary with frenzi's pr + this pr's sdl hints, and it does allow touch tapping with pen aim (with noticeably more latency than regular touch aim and tapping), but it breaks hover input completely (can only drag) (logs if ya need 'em)

The logs confirm you're using the latest SDL3 👍

When you say that hover is broken, is it broken only in gameplay, or also in menus? If it's only gameplay, try applying this patch and see if the hovering playstyle works.

Which device are you using to test this?

When you say there's noticeable latency, do you think that is display latency or pen input latency? (I understand that it might be hard to tell.) Could be that there is an overlay display when using the pen, kicking osu! out of exclusive fullscreen. In my testing, I noticed a microstutter when the pen entered or left the hover range (indicative of fullscreen overlay shenanigans), but that might be due to Wacom drivers.

[Susko3]

@Walavouchey this branch ppy/osu@master...Susko3:osu:enable-mouse-hover-touch-click-play-style should work, with and without frenzi's PR. It was build with hovering playstyle in mind, but pressing the pen down shouldn't be too broken. Please give it a test.

[Walavouchey]

Which device are you using to test this?

Surface Pro 8

When you say that hover is broken, is it broken only in gameplay, or also in menus? If it's only gameplay, try applying this patch and see if the hovering playstyle works.

everywhere (immediately noticeable when opening the game and using the pen)

When you say there's noticeable latency, do you think that is display latency or pen input latency? (I understand that it might be hard to tell.)

it's not like the framerate suffers or that there are microstutters (no spikes on the frame graph either). pen taps, touch taps, and touch taps while dragging with a finger are fine with no perceived latency, but specifically the touch taps while dragging the pen register later (i get around +50 ms hit error).

Could be that there is an overlay display when using the pen, kicking osu! out of exclusive fullscreen. In my testing, I noticed a microstutter when the pen entered or left the hover range (indicative of fullscreen overlay shenanigans), but that might be due to Wacom drivers.

no such stutters that i notice. i think windows vs fullscreen might make a few ms difference on my device but it's harder to notice than the latency i'm describing

this branch ppy/osu@master...Susko3:osu:enable-mouse-hover-touch-click-play-style should work, with and without frenzi's PR. It was build with hovering playstyle in mind, but pressing the pen down shouldn't be too broken. Please give it a test.

all with new sdl3 binary
that branch logs-with-frenzy-framework.zip:

1. hover not broken, touch taps while dragging or hovering pen still have latency
2. during gameplay (not menu), dragging the pen leaves the cursor motionless where you started the drag, unless you started dragging on a circle (a bit inconsistently)

that branch logs-without-modified-framework.zip:

1. hover not broken, touch taps while dragging or hovering pen still have latency
2. dragging the pen causes the cursor to lag (as in its position updates at a lower frequency)
3. touch device mod flickers off and on (mostly on) while dragging the pen (seen in song select)

the patch you linked instead of that branch logs-with-frenzy-framework-susko-patch-2.zip:

1. hover not broken, touch taps while dragging or hovering pen still have latency
   ^ best so far!

the patch you linked instead of that branch logs-without-modified-framework-susko-patch-2.zip

1. hover not broken
2. touch taps while dragging or hovering the pen put the cursor where you tap (can't play at all)
3. dragging the pen causes the cursor to lag (as in its position updates at a lower frequency)
4. touch device mod flickers off and on (mostly on) while dragging the pen (seen in song select)

in all these cases, TD mod is on while dragging pen and off when hovering

[smoogipoo]

New SDL3-CS package: https://www.nuget.org/packages/ppy.SDL3-CS/2025.127.0

[Susko3]

Looks good on my part.

Further testing can be done based on this PR, to reduce possible error when setting up the environment. For example, logs-without-modified-framework.zip show that this test was done on an older commit, before c901353.

@Walavouchey please give it a test again, this PR + ppy/osu@master...Susko3:osu:enable-mouse-hover-touch-click-play-style, no additional mangling with SDL3.dll needed. Touch device mod should not activate if you only use the pen. If it does, check what InputHandlers are reporting inputs in Ctrl+F2.

Also useful is to enable SDL event logging, to check if we're receiving correct events:

diff --git a/osu.Framework/Platform/SDL3/SDL3Window.cs b/osu.Framework/Platform/SDL3/SDL3Window.cs
index 8f7783571..70a895b28 100644
--- a/osu.Framework/Platform/SDL3/SDL3Window.cs
+++ b/osu.Framework/Platform/SDL3/SDL3Window.cs
@@ -213,6 +213,7 @@ public virtual void Create()
             SDL_SetHint(SDL_HINT_PEN_TOUCH_EVENTS, "0"u8);
             SDL_SetHint(SDL_HINT_PEN_MOUSE_EVENTS, "0"u8);
             SDL_SetHint(SDL_HINT_IME_IMPLEMENTED_UI, "composition"u8);
+            SDL_SetHint(SDL_HINT_EVENT_LOGGING, "2"u8);
 
             SDLWindowHandle = SDL_CreateWindow(title, Size.Width, Size.Height, flags);
 

[Walavouchey]

@Walavouchey please give it a test again, this PR + ppy/osu@master...Susko3:osu:enable-mouse-hover-touch-click-play-style, no additional mangling with SDL3.dll needed. Touch device mod should not activate if you only use the pen. If it does, check what InputHandlers are reporting inputs in Ctrl+F2.

logs .osr replay enabled sdl logs

• works ok, same as test 3 in my previous comment
• playing with only the pen doesn't activate TD, while pen + touch does
• looks like i didn't have mouse buttons disabled, so i miss the first note when dragging the pen and tapping for the first time (normally happens with keyboard + pen but not with two-hand touch)

[smoogipoo]

Does the above mean this PR is ready to review?

[Susko3]

Yep, ready for review.

[peppy]

Let's get this in and give ample time for devs to dogfood the change before we roll out the next major release.