feat(openxr): Monado playspace mover

Co-authored-by: RinLovesYou <xxklintan123xx@gmail.com>

src/backend/openxr/playspace.rs

@@ -0,0 +1,98 @@
+use std::ffi::c_void;
+
+use glam::Vec3A;
+use libloading::{Library, Symbol};
+
+use crate::{backend::common::OverlayContainer, state::AppState};
+
+use super::{helpers, input::DoubleClickCounter, overlay::OpenXrOverlayData};
+
+pub(super) struct PlayspaceMover {
+    drag_hand: Option<usize>,
+    offset: Vec3A,
+    start_position: Vec3A,
+
+    double_click_counter: DoubleClickCounter,
+
+    libmonado: Library,
+    mnd_root: *mut c_void,
+    playspace_move: extern "C" fn(*mut c_void, f32, f32, f32) -> i32,
+}
+
+impl PlayspaceMover {
+    pub fn try_new() -> anyhow::Result<Self> {
+        unsafe {
+            let libmonado = helpers::find_libmonado()?;
+
+            let root_create: Symbol<extern "C" fn(*mut *mut c_void) -> i32> =
+                libmonado.get(b"mnd_root_create\0")?;
+            let playspace_move: Symbol<extern "C" fn(*mut c_void, f32, f32, f32) -> i32> =
+                libmonado.get(b"mnd_root_playspace_move\0")?;
+            let playspace_move_raw = *playspace_move;
+
+            let mut root: *mut c_void = std::ptr::null_mut();
+
+            let ret = root_create(&mut root);
+
+            if ret != 0 {
+                anyhow::bail!("Failed to create root, code: {}", ret);
+            }
+
+            Ok(Self {
+                drag_hand: None,
+                offset: Vec3A::ZERO,
+                start_position: Vec3A::ZERO,
+
+                double_click_counter: DoubleClickCounter::new(),
+
+                libmonado,
+                mnd_root: root,
+                playspace_move: playspace_move_raw,
+            })
+        }
+    }
+
+    pub fn update(&mut self, overlays: &mut OverlayContainer<OpenXrOverlayData>, state: &AppState) {
+        if let Some(hand) = self.drag_hand {
+            let pointer = &state.input_state.pointers[hand];
+            if !pointer.now.space_drag {
+                self.drag_hand = None;
+                log::info!("End space drag");
+                return;
+            }
+
+            let hand_pos = state.input_state.pointers[hand].pose.translation;
+            let relative_pos = hand_pos - self.start_position;
+
+            overlays.iter_mut().for_each(|overlay| {
+                if overlay.state.grabbable {
+                    overlay.state.dirty = true;
+                    overlay.state.transform.translation += relative_pos * -1.0;
+                }
+            });
+
+            self.offset += relative_pos;
+            self.apply_offset();
+        } else {
+            for (i, pointer) in state.input_state.pointers.iter().enumerate() {
+                if pointer.now.space_drag
+                    && !pointer.before.space_drag
+                    && self.double_click_counter.click()
+                {
+                    self.drag_hand = Some(i);
+                    self.start_position = pointer.pose.translation;
+                    break;
+                }
+            }
+        }
+    }
+
+    pub fn reset(&mut self) {
+        self.offset = Vec3A::ZERO;
+        self.start_position = Vec3A::ZERO;
+    }
+
+    fn apply_offset(&mut self) {
+        (self.playspace_move)(self.mnd_root, self.offset.x, self.offset.y, self.offset.z);
+    }
+}