Confused about warp requirements.

[codecnotsupported]

For SDL2 warping isn't supported if the cursor is visible. However when I removed the check it still works fine.

SDL/src/video/wayland/SDL_waylandmouse.c

Lines 639 to 655 in 0805990

	static void Wayland_WarpMouse(SDL_Window *window, int x, int y)
	{
	SDL_VideoDevice *vd = SDL_GetVideoDevice();
	SDL_VideoData *d = vd->driverdata;
	struct SDL_WaylandInput *input = d->input;
	if (input->cursor_visible == SDL_TRUE) {
	SDL_Unsupported();
	} else if (input->warp_emulation_prohibited) {
	SDL_Unsupported();
	} else {
	if (!d->relative_mouse_mode) {
	Wayland_input_lock_pointer(input);
	input->relative_mode_override = SDL_TRUE;
	}
	}
	}

Why is the visible check there in the first place?

For SDL3:

SDL/src/video/wayland/SDL_waylandmouse.c

Lines 572 to 614 in 1103294

	static int Wayland_WarpMouse(SDL_Window *window, float x, float y)
	{
	SDL_VideoDevice *vd = SDL_GetVideoDevice();
	SDL_VideoData *d = vd->driverdata;
	SDL_WindowData *wind = window->driverdata;
	struct SDL_WaylandInput *input = d->input;
	if (input->cursor_visible || (input->warp_emulation_prohibited && !d->relative_mouse_mode)) {
	if (d->pointer_constraints) {
	const SDL_bool toggle_lock = !wind->locked_pointer;
	/* The pointer confinement protocol allows setting a hint to warp the pointer,
	* but only when the pointer is locked.
	*
	* Lock the pointer, set the position hint, unlock, and hope for the best.
	*/
	if (toggle_lock) {
	Wayland_input_lock_pointer(input, window);
	}
	if (wind->locked_pointer) {
	zwp_locked_pointer_v1_set_cursor_position_hint(wind->locked_pointer, wl_fixed_from_double(x), wl_fixed_from_double(y));
	wl_surface_commit(wind->surface);
	}
	if (toggle_lock) {
	Wayland_input_unlock_pointer(input, window);
	}
	/* NOTE: There is a pending warp event under discussion that should replace this when available.
	* https://gitlab.freedesktop.org/wayland/wayland/-/merge_requests/340
	*/
	SDL_SendMouseMotion(0, window, SDL_GLOBAL_MOUSE_ID, SDL_FALSE, x, y);
	} else {
	return SDL_SetError("wayland: mouse warp failed; compositor lacks support for the required zwp_pointer_confinement_v1 protocol");
	}
	} else if (input->warp_emulation_prohibited) {
	return SDL_Unsupported();
	} else if (!d->relative_mouse_mode) {
	Wayland_input_lock_pointer(input, window);
	input->relative_mode_override = SDL_TRUE;
	}
	return 0;
	}

I don't understand the following requirement:

SDL/src/video/wayland/SDL_waylandmouse.c

Line 579 in 1103294

if (input->cursor_visible || (input->warp_emulation_prohibited && !d->relative_mouse_mode)) {

Why does the visibility of the cursor matter?
Why does it work if warp emulation is prohibited and the mouse mode is absolute?

[Kontrabant]

It's a hack to work around older games that handle camera movement by hiding the cursor and constantly warping it back to the center while measuring the distance that it moved. Special care has to be taken in this scenario, or the cursor can wind up outside of the window and cannot be warped back in.

[codecnotsupported]

It's a hack to work around older games that handle camera movement by hiding the cursor and constantly warping it back to the center while measuring the distance that it moved. Special care has to be taken in this scenario, or the cursor can wind up outside of the window and cannot be warped back in.

I may be misunderstanding/missing a piece of information, but why not allow warping regardless of visibility?