There is no ([not yet?](https://gitlab.freedesktop.org/wayland/wayland-protocols/-/merge_requests/33...)) dedicated protocol for requesting pointer warps, but it's possible to request one with `zwp_locked_pointer_v1.set_cursor_position_hint` which may be performed when the pointer is unlocked. The idea is to quickly lock/set position/unlock. This is used by SDL (in some cases: [SDL_MOUSE_EMULATE_WARP_WITH_RELATIVE](https://wiki.libsdl.org/SDL3/SDL_HINT_MOUSE_EMULATE_WARP_WITH_RELATIVE)) and Xwayland. The limitation is/will be that the compositor will ignore requests to warp the pointer outside of surface bounds.
What I'd like to have working is the auto cursor placement feature of some applications, where they just want to call SetCursorPos towards specific UI elements inside their single window, and usually they'll be unclipped and have a visible cursor while doing this.
This patch also happens to allow mouselook to work in applications which use SetCursorPos for mouselook and aren't getting covered by the heuristics that turn on Wayland relative motion (for some reason the driver thinks the cursor is visible). Seems to affect Half-Life (GoldSrc) on my system. Though force enabling relative motion with an environment variable in a custom build or somehow improving the heuristics will also fix that.
A suface/pointer can only have one lock or confinement, and this implementation depends on the pointer lock. So if needed, I temporarily unlock/unconfine in order to do the warp then relock/reconfine. I modified `wayland_pointer_update_constraint` so I don't have to temporarily disable relative motion during this in case it's enabled. I think it's safe/a no-op to attempt pointer warps while using relative motion, as according to the protocol the warp will not generate a relative motion event, and while there will be a wl_pointer motion event, they're ignored while relative motion is being used.
-- v2: winewayland: Implement SetCursorPos via pointer lock. winewayland: Update locked pointer position hint.