Accel works correctly like this for some magical reason

Still need to figure out why we need to sandwich accel TWICE.. but only if we adjust it by reference, otherwise we can do it once...

.gitignore

@@ -46,3 +46,4 @@ local.properties
 
 # Ignore temporary config
 vrconfig.yml.tmp
+*.DS_Store

gui/src/components/widgets/IMUVisualizerWidget.tsx

@@ -110,14 +110,14 @@ export function IMUVisualizerWidget({ tracker }: { tracker: TrackerDataT }) {
 
   const rotationRaw = useRawRotationEulerDegrees();
   const rotationIdent = useIdentAdjRotationEulerDegrees() || rotationRaw;
-  const quat =
-    tracker?.rotationIdentityAdjusted ||
-    tracker?.rotation ||
-    new THREE.Quaternion();
-  const vec =
-    tracker?.linearAcceleration ||
-    tracker?.rawAcceleration ||
-    new THREE.Vector3();
+  const quat = useMemo(() => {
+    return tracker?.rotationIdentityAdjusted || tracker?.rotation || new THREE.Quaternion()
+  }, [tracker])
+
+  const vec = useMemo(() => {
+    return new Vector3().copy(tracker?.linearAcceleration || tracker?.rawAcceleration || {x: 0, y: 0, z: 0})  // .applyQuaternion(new THREE.Quaternion().copy(quat))
+  }, [tracker, quat])
+
     const mag =
         tracker?.rawMagneticVector ||
         new THREE.Vector3();

server/core/src/main/java/dev/slimevr/tracking/trackers/Tracker.kt

@@ -6,6 +6,7 @@ import dev.slimevr.tracking.trackers.TrackerPosition.Companion.getByDesignation
 import dev.slimevr.tracking.trackers.udp.IMUType
 import dev.slimevr.tracking.trackers.udp.MagnetometerStatus
 import dev.slimevr.tracking.trackers.udp.TrackerDataType
+import io.eiren.math.FloatMath.INV_SQRT_TWO
 import io.eiren.util.BufferedTimer
 import io.github.axisangles.ktmath.Quaternion
 import io.github.axisangles.ktmath.Vector3
@@ -383,6 +384,8 @@ class Tracker @JvmOverloads constructor(
 	 * Gets the world-adjusted acceleration
 	 */
 	fun getAcceleration(): Vector3 = if (needsReset) {
+		//_acceleration
+		//getAdjustedRotation().sandwich(_acceleration)
 		resetsHandler.getReferenceAdjustedAccel(_rotation, _acceleration)
 	} else {
 		_acceleration
@@ -453,4 +456,15 @@ class Tracker @JvmOverloads constructor(
 	fun resetFilteringQuats(reference: Quaternion) {
 		filteringHandler.resetMovingAverage(getAdjustedRotation(), reference)
 	}
+
+	companion object {
+		/**
+		 * Turn 90 degrees around LEFT axis to make the base position of the tracker standing upwards
+		 * instead of laying on the back
+		 */
+		private val rotationOffset = Quaternion(INV_SQRT_TWO, -INV_SQRT_TWO, 0f, 0f)
+		fun axisRemap(v: Vector3): Vector3 = Vector3(v.x, -v.y, -v.z)
+		fun axisOffset(v: Vector3): Vector3 = axisRemap(v) //rotationOffset.sandwich(rotationOffset.sandwich(v))
+		fun axisOffset(q: Quaternion): Quaternion = rotationOffset * q
+	}
 }

server/core/src/main/java/dev/slimevr/tracking/trackers/udp/TrackersUDPServer.kt

@@ -1,16 +1,14 @@
 package dev.slimevr.tracking.trackers.udp
 
-import com.jme3.math.FastMath
 import dev.slimevr.NetworkProtocol
 import dev.slimevr.VRServer
 import dev.slimevr.config.config
 import dev.slimevr.protocol.rpc.MAG_TIMEOUT
 import dev.slimevr.tracking.trackers.*
+import dev.slimevr.tracking.trackers.Tracker.Companion.axisOffset
 import io.eiren.util.Util
 import io.eiren.util.collections.FastList
 import io.eiren.util.logging.LogManager
-import io.github.axisangles.ktmath.Quaternion.Companion.fromRotationVector
-import io.github.axisangles.ktmath.Vector3
 import kotlinx.coroutines.*
 import solarxr_protocol.rpc.ResetType
 import java.net.DatagramPacket
@@ -389,13 +387,12 @@ class TrackersUDPServer(private val port: Int, name: String, private val tracker
 
 			is RotationPacket -> {
 				var rot = packet.rotation
-				rot = AXES_OFFSET.times(rot)
+				rot = axisOffset(rot)
 				tracker = connection?.getTracker(packet.sensorId)
 				if (tracker == null) return
 				tracker.setRotation(rot)
 				if (packet is UDPPacket23RotationAndAcceleration) {
-					// Switch x and y around to adjust for different axes
-					tracker.setAcceleration(Vector3(packet.acceleration.y, packet.acceleration.x, packet.acceleration.z))
+					tracker.setAcceleration(axisOffset(packet.acceleration))
 				}
 				tracker.dataTick()
 			}
@@ -404,7 +401,7 @@ class TrackersUDPServer(private val port: Int, name: String, private val tracker
 				tracker = connection?.getTracker(packet.sensorId)
 				if (tracker == null) return
 				var rot17 = packet.rotation
-				rot17 = AXES_OFFSET * rot17
+				rot17 = axisOffset(rot17)
 				when (packet.dataType) {
 					UDPPacket17RotationData.DATA_TYPE_NORMAL -> {
 						tracker.setRotation(rot17)
@@ -427,8 +424,7 @@ class TrackersUDPServer(private val port: Int, name: String, private val tracker
 			is UDPPacket4Acceleration -> {
 				tracker = connection?.getTracker(packet.sensorId)
 				if (tracker == null) return
-				// Switch x and y around to adjust for different axes
-				tracker.setAcceleration(Vector3(packet.acceleration.y, packet.acceleration.x, packet.acceleration.z))
+				tracker.setAcceleration(axisOffset(packet.acceleration))
 			}
 
 			is UDPPacket10PingPong -> {
@@ -602,10 +598,6 @@ class TrackersUDPServer(private val port: Int, name: String, private val tracker
 	}
 
 	companion object {
-		/**
-		 * Change between IMU axes and OpenGL/SteamVR axes
-		 */
-		private val AXES_OFFSET = fromRotationVector(-FastMath.HALF_PI, 0f, 0f)
 		private const val RESET_SOURCE_NAME = "TrackerServer"
 		private fun packetToString(packet: DatagramPacket?): String {
 			val sb = StringBuilder()

server/core/src/main/java/io/eiren/math/FloatMath.kt

@@ -17,7 +17,7 @@ object FloatMath {
 	const val ZERO_TOLERANCE_D: Double = 0.0001
 
 	val SQRT_TWO: Float = kotlin.math.sqrt(2.0).toFloat()
-	val INV_SQRT_TWO: Float = 1f / SQRT_TWO
+	val INV_SQRT_TWO: Float = (1.0 / kotlin.math.sqrt(2.0)).toFloat()
 	val SQRT_THREE: Float = kotlin.math.sqrt(3.0).toFloat()
 	val INV_SQRT_THREE: Float = 1f / SQRT_THREE
 	const val TWO_FPI: Float = PI * 2

server/desktop/src/main/java/dev/slimevr/desktop/tracking/trackers/hid/TrackersHID.kt

@@ -1,9 +1,9 @@
 package dev.slimevr.desktop.tracking.trackers.hid
 
-import com.jme3.math.FastMath
 import dev.slimevr.VRServer
 import dev.slimevr.tracking.trackers.Device
 import dev.slimevr.tracking.trackers.Tracker
+import dev.slimevr.tracking.trackers.Tracker.Companion.axisOffset
 import dev.slimevr.tracking.trackers.TrackerStatus
 import dev.slimevr.tracking.trackers.udp.BoardType
 import dev.slimevr.tracking.trackers.udp.IMUType
@@ -11,7 +11,6 @@ import dev.slimevr.tracking.trackers.udp.MCUType
 import dev.slimevr.tracking.trackers.udp.MagnetometerStatus
 import io.eiren.util.logging.LogManager
 import io.github.axisangles.ktmath.Quaternion
-import io.github.axisangles.ktmath.Quaternion.Companion.fromRotationVector
 import io.github.axisangles.ktmath.Vector3
 import org.hid4java.HidDevice
 import org.hid4java.HidException
@@ -412,7 +411,7 @@ class TrackersHID(name: String, private val trackersConsumer: Consumer<Tracker>)
 							// x y z w -> w x y z
 							var rot = Quaternion(q[3].toFloat(), q[0].toFloat(), q[1].toFloat(), q[2].toFloat())
 							val scaleRot = 1 / (1 shl 15).toFloat() // compile time evaluation
-							rot = AXES_OFFSET.times(scaleRot).times(rot) // no division
+							rot = axisOffset(rot * scaleRot) // no division
 							tracker.setRotation(rot)
 						}
 						if (packetType == 2) {
@@ -431,7 +430,7 @@ class TrackersHID(name: String, private val trackersConsumer: Consumer<Tracker>)
 							val s = sin(a)
 							val k = s * invSqrtD
 							var rot = Quaternion(cos(a), k * v[0], k * v[1], k * v[2])
-							rot = AXES_OFFSET.times(rot) // no division
+							rot = axisOffset(rot) // no division
 							tracker.setRotation(rot)
 						}
 						if (packetType == 1 || packetType == 2) {
@@ -444,6 +443,7 @@ class TrackersHID(name: String, private val trackersConsumer: Consumer<Tracker>)
 							// Front side (facing out) is +Z
 							val scaleAccel = 1 / (1 shl 7).toFloat() // compile time evaluation
 							var acceleration = Vector3(a[0].toFloat(), a[1].toFloat(), a[2].toFloat()).times(scaleAccel) // no division
+							acceleration = axisOffset(acceleration)
 							tracker.setAcceleration(acceleration)
 						}
 						if (packetType == 4) {
@@ -528,10 +528,6 @@ class TrackersHID(name: String, private val trackersConsumer: Consumer<Tracker>)
 	}
 
 	companion object {
-		/**
-		 * Change between IMU axes and OpenGL/SteamVR axes
-		 */
-		private val AXES_OFFSET = fromRotationVector(-FastMath.HALF_PI, 0f, 0f)
 		private const val resetSourceName = "TrackerServer"
 	}
 }