From fafa579eb29cd1cca4c63e689916cf903a4e886f Mon Sep 17 00:00:00 2001
From: wheaney <42350981+wheaney@users.noreply.github.com>
Date: Tue, 22 Jul 2025 22:43:14 -0700
Subject: [PATCH] Fix look-ahead and euler angle ordering issues

---
 kwin/src/breezydesktopeffect.cpp  |  5 +++--
 kwin/src/qml/CameraController.qml | 20 +++++++-------------
 2 files changed, 10 insertions(+), 15 deletions(-)

diff --git a/kwin/src/breezydesktopeffect.cpp b/kwin/src/breezydesktopeffect.cpp
index d298cf9..a9a5f30 100644
--- a/kwin/src/breezydesktopeffect.cpp
+++ b/kwin/src/breezydesktopeffect.cpp
@@ -245,10 +245,11 @@ void BreezyDesktopEffect::updateImuRotation() {
         return;
     }
 
-    QQuaternion quatT0(imuData[3], imuData[0], imuData[1], imuData[2]);
+    // convert NWU to EUS by passing root.rotation values: -y, z, -x
+    QQuaternion quatT0(imuData[3], -imuData[1], imuData[2], -imuData[0]);
 
     memcpy(imuData, data + 109 + sizeof(imuData), sizeof(imuData));
-    QQuaternion quatT1(imuData[3], imuData[0], imuData[1], imuData[2]);
+    QQuaternion quatT1(imuData[3], -imuData[1], imuData[2], -imuData[0]);
 
     // set imuRotations to the last two rotations, leave out the elapsed time
     m_imuRotations.clear();
diff --git a/kwin/src/qml/CameraController.qml b/kwin/src/qml/CameraController.qml
index 9eea8c4..033f56e 100644
--- a/kwin/src/qml/CameraController.qml
+++ b/kwin/src/qml/CameraController.qml
@@ -6,7 +6,6 @@ Item {
 
     required property Camera camera
 
-    property vector3d rotation: Qt.vector3d(0, 0, 0)
     property real radius: 2000
 
     property real speed: 1
@@ -16,17 +15,16 @@ Item {
     implicitWidth: parent.width
     implicitHeight: parent.height
 
-    onRotationChanged: root.updateCamera();
-    onRadiusChanged: root.updateCamera();
+    // onRadiusChanged: root.updateCamera();
 
-    function updateCamera() {
+    function updateCamera(rotation) {
         const theta = 90 * Math.PI / 180;
         const phi = 0.0;
 
         camera.position = Qt.vector3d(radius * Math.sin(phi) * Math.sin(theta),
                                       radius * Math.cos(theta),
                                       radius * Math.cos(phi) * Math.sin(theta));
-        camera.eulerRotation = root.rotation;
+        camera.eulerRotation = rotation;
     }
 
     // how far to look ahead is how old the IMU data is plus a constant that is either the default for this device or an override
@@ -38,7 +36,6 @@ Item {
     }
 
     function applyLookAhead(quatT0, quatT1, elapsedTimeMs, lookAheadMs) {
-        console.log(`Applying look-ahead with ${elapsedTimeMs} and ${lookAheadMs}`);
         // convert both quats to euler angles
         const eulerT0 = quatT0.toEulerAngles();
         const eulerT1 = quatT1.toEulerAngles();
@@ -51,11 +48,10 @@ Item {
         // how much of the delta to apply based on the look-ahead time
         const timeConstant = lookAheadMs / elapsedTimeMs;
 
-        // compute the look-ahead angles and convert NWU to EUS by passing root.rotation values: -y, z, -x
         return Qt.vector3d(
-            -eulerT0.y + deltaY * timeConstant,
+            eulerT0.x + deltaX * timeConstant,
+            eulerT0.y + deltaY * timeConstant,
             eulerT0.z + deltaZ * timeConstant,
-            -eulerT0.x + deltaX * timeConstant
         );
     }
 
@@ -69,15 +65,13 @@ Item {
     FrameAnimation {
         running: true
         onTriggered: {
-            console.log("FrameAnimation triggered, updating camera rotation");
             if (root.useImuRotation && root.imuRotations && root.imuRotations.length > 0) {
-                console.log("Using IMU rotation for camera control");
-                root.rotation = applyLookAhead(
+                updateCamera(applyLookAhead(
                     root.imuRotations[0],
                     root.imuRotations[1],
                     root.imuTimeElapsedMs,
                     lookAheadMS(root.imuTimestamp, root.lookAheadConstant, -1)
-                );
+                ));
             }
         }
     }