Merge webxr repository (#35228)

Signed-off-by: Martin Robinson <mrobinson@igalia.com>

components/shared/webxr/util.rs

@@ -0,0 +1,129 @@
+use crate::FrameUpdateEvent;
+use crate::HitTestId;
+use crate::HitTestSource;
+use euclid::Transform3D;
+
+#[derive(Clone, Copy, Debug)]
+#[cfg_attr(feature = "ipc", derive(serde::Serialize, serde::Deserialize))]
+pub struct ClipPlanes {
+    pub near: f32,
+    pub far: f32,
+    /// Was there an update that needs propagation to the client?
+    update: bool,
+}
+
+impl Default for ClipPlanes {
+    fn default() -> Self {
+        ClipPlanes {
+            near: 0.1,
+            far: 1000.,
+            update: false,
+        }
+    }
+}
+
+impl ClipPlanes {
+    pub fn update(&mut self, near: f32, far: f32) {
+        self.near = near;
+        self.far = far;
+        self.update = true;
+    }
+
+    /// Checks for and clears the pending update flag
+    pub fn recently_updated(&mut self) -> bool {
+        if self.update {
+            self.update = false;
+            true
+        } else {
+            false
+        }
+    }
+}
+
+#[derive(Clone, Debug, Default)]
+#[cfg_attr(feature = "ipc", derive(serde::Serialize, serde::Deserialize))]
+/// Holds on to hit tests
+pub struct HitTestList {
+    tests: Vec<HitTestSource>,
+    uncommitted_tests: Vec<HitTestSource>,
+}
+
+impl HitTestList {
+    pub fn request_hit_test(&mut self, source: HitTestSource) {
+        self.uncommitted_tests.push(source)
+    }
+
+    pub fn commit_tests(&mut self) -> Vec<FrameUpdateEvent> {
+        let mut events = vec![];
+        for test in self.uncommitted_tests.drain(..) {
+            events.push(FrameUpdateEvent::HitTestSourceAdded(test.id));
+            self.tests.push(test);
+        }
+        events
+    }
+
+    pub fn tests(&self) -> &[HitTestSource] {
+        &self.tests
+    }
+
+    pub fn cancel_hit_test(&mut self, id: HitTestId) {
+        self.tests.retain(|s| s.id != id);
+        self.uncommitted_tests.retain(|s| s.id != id);
+    }
+}
+
+#[inline]
+/// Construct a projection matrix given the four angles from the center for the faces of the viewing frustum
+pub fn fov_to_projection_matrix<T, U>(
+    left: f32,
+    right: f32,
+    top: f32,
+    bottom: f32,
+    clip_planes: ClipPlanes,
+) -> Transform3D<f32, T, U> {
+    let near = clip_planes.near;
+    // XXXManishearth deal with infinite planes
+    let left = left.tan() * near;
+    let right = right.tan() * near;
+    let top = top.tan() * near;
+    let bottom = bottom.tan() * near;
+
+    frustum_to_projection_matrix(left, right, top, bottom, clip_planes)
+}
+
+#[inline]
+/// Construct matrix given the actual extent of the viewing frustum on the near plane
+pub fn frustum_to_projection_matrix<T, U>(
+    left: f32,
+    right: f32,
+    top: f32,
+    bottom: f32,
+    clip_planes: ClipPlanes,
+) -> Transform3D<f32, T, U> {
+    let near = clip_planes.near;
+    let far = clip_planes.far;
+
+    let w = right - left;
+    let h = top - bottom;
+    let d = far - near;
+
+    // Column-major order
+    Transform3D::new(
+        2. * near / w,
+        0.,
+        0.,
+        0.,
+        0.,
+        2. * near / h,
+        0.,
+        0.,
+        (right + left) / w,
+        (top + bottom) / h,
+        -(far + near) / d,
+        -1.,
+        0.,
+        0.,
+        -2. * far * near / d,
+        0.,
+    )
+}