From 0aa41a912be626ffb00e23ff14f5b250882f1bc2 Mon Sep 17 00:00:00 2001
From: wheaney <42350981+wheaney@users.noreply.github.com>
Date: Fri, 16 Jan 2026 13:11:27 -0800
Subject: [PATCH] Fix issue with double-counting lens position changes with
 6DoF

---
 kwin/src/breezydesktopeffect.cpp  | 13 +++++++++++++
 kwin/src/breezydesktopeffect.h    |  4 ++++
 kwin/src/qml/CameraController.qml |  8 +++++++-
 kwin/src/qml/Displays.qml         |  6 +-----
 4 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/kwin/src/breezydesktopeffect.cpp b/kwin/src/breezydesktopeffect.cpp
index b5ceab0..c1256e8 100644
--- a/kwin/src/breezydesktopeffect.cpp
+++ b/kwin/src/breezydesktopeffect.cpp
@@ -469,6 +469,10 @@ quint64 BreezyDesktopEffect::poseTimestamp() const {
     return m_poseTimestamp;
 }
 
+bool BreezyDesktopEffect::poseHasPosition() const {
+    return m_poseHasPosition;
+}
+
 QList<qreal> BreezyDesktopEffect::lookAheadConfig() const {
     return m_lookAheadConfig;
 }
@@ -718,7 +722,16 @@ void BreezyDesktopEffect::updatePose() {
                                 << "diagonalFOV:" << m_diagonalFOV;
         activate();
         m_enabled = true;
+        m_poseHasPosition = false;
+        auto driverStateOpt = XRDriverIPC::instance().retrieveDriverState();
+        if (driverStateOpt) {
+            QJsonObject driverState = driverStateOpt.value();
+            if (driverState.contains(QStringLiteral("connected_device_pose_has_position"))) {
+                m_poseHasPosition = driverState.value(QStringLiteral("connected_device_pose_has_position")).toBool();
+            }
+        }
         Q_EMIT enabledStateChanged();
+        Q_EMIT poseHasPositionChanged();
         activatedAt = currentTimeMs;
     }
     
diff --git a/kwin/src/breezydesktopeffect.h b/kwin/src/breezydesktopeffect.h
index 560dbb0..9be5552 100644
--- a/kwin/src/breezydesktopeffect.h
+++ b/kwin/src/breezydesktopeffect.h
@@ -25,6 +25,7 @@ namespace KWin
         Q_PROPERTY(bool zoomOnFocusEnabled READ isZoomOnFocusEnabled WRITE setZoomOnFocusEnabled NOTIFY zoomOnFocusChanged)
         Q_PROPERTY(int lookingAtScreenIndex READ lookingAtScreenIndex WRITE setLookingAtScreenIndex)
         Q_PROPERTY(bool poseResetState READ poseResetState NOTIFY poseResetStateChanged)
+        Q_PROPERTY(bool poseHasPosition READ poseHasPosition NOTIFY poseResetStateChanged)
         Q_PROPERTY(QList<QQuaternion> poseOrientations READ poseOrientations)
         Q_PROPERTY(QVector3D posePosition READ posePosition)
         Q_PROPERTY(quint32 poseTimeElapsedMs READ poseTimeElapsedMs)
@@ -81,6 +82,7 @@ namespace KWin
         quint32 poseTimeElapsedMs() const;
         quint64 poseTimestamp() const;
         bool poseResetState() const;
+        bool poseHasPosition() const;
         QList<qreal> lookAheadConfig() const;
         qreal lookAheadOverride() const;
         void setLookAheadOverride(qreal override);
@@ -138,6 +140,7 @@ namespace KWin
         void enabledStateChanged();
         void zoomOnFocusChanged();
         void poseResetStateChanged();
+        void poseHasPositionChanged();
         void sbsEnabledChanged();
         void smoothFollowEnabledChanged();
         void devicePropertiesChanged();
@@ -175,6 +178,7 @@ namespace KWin
         int m_lookingAtScreenIndex = -1;
         int m_effectTargetScreenIndex = -1;
         bool m_poseResetState;
+        bool m_poseHasPosition = false;
         QList<QQuaternion> m_poseOrientations;
         QVector3D m_posePosition;
         quint32 m_poseTimeElapsedMs;
diff --git a/kwin/src/qml/CameraController.qml b/kwin/src/qml/CameraController.qml
index a2820a1..c82971c 100644
--- a/kwin/src/qml/CameraController.qml
+++ b/kwin/src/qml/CameraController.qml
@@ -62,7 +62,13 @@ Item {
                 effect.lookAheadOverride
             )
         );
-        camera.position = position.times(fovDetails.fullScreenDistancePixels).plus(orientations[0].times(Qt.vector3d(0, 0, -fovDetails.lensDistancePixels)));
+        let lensVector = Qt.vector3d(0, 0, -fovDetails.lensDistancePixels);
+
+        // if we only have 3DoF, account for a bit of positional change based on orientation,
+        // don't do this for 6DoF to prevent doubling the positional movement due to rotation
+        if (!effect.poseHasPosition) lensVector = orientations[0].times(lensVector);
+
+        camera.position = position.times(fovDetails.fullScreenDistancePixels).plus(lensVector);
         
         sampleCounter += 1;
         if (sampleCounter === 60) {
diff --git a/kwin/src/qml/Displays.qml b/kwin/src/qml/Displays.qml
index f488605..db9904f 100644
--- a/kwin/src/qml/Displays.qml
+++ b/kwin/src/qml/Displays.qml
@@ -64,7 +64,6 @@ QtObject {
     }
 
     function buildFovDetails(screens, viewportWidth, viewportHeight, viewportDiagonalFOV, lensDistanceRatio, defaultDisplayDistance, wrappingChoice, distanceAdjustedSize) {
-        console.log(`Breezy - Building FOV details with viewport ${viewportWidth}x${viewportHeight}, diagonal FOV ${viewportDiagonalFOV} degrees, lens distance ratio ${lensDistanceRatio}, default display distance ${defaultDisplayDistance}, wrapping choice ${wrappingChoice}, distance adjusted size ${distanceAdjustedSize}`);
         const aspect = viewportWidth / viewportHeight;
         const fovLengths = diagonalToCrossFOVs(degreeToRadian(viewportDiagonalFOV), aspect);
 
@@ -101,7 +100,7 @@ QtObject {
         // distance of a display at the default (most zoomed out) distance from the pivot point
         const completeScreenDistancePixels = fullScreenDistancePixels * defaultDisplayDistance;
 
-        const details = {
+        return {
             widthPixels: viewportWidth,
             distanceAdjustedSize,
             sizeAdjustedWidthPixels: viewportWidth * distanceAdjustedSize,
@@ -115,9 +114,6 @@ QtObject {
             monitorWrappingScheme,
             curvedDisplay: effect.curvedDisplay
         };
-
-        console.log("Breezy - FOV Details:", details);
-        return details;
     }
 
     // Utility constant