Reverted some lines of panning to re-enable panning on Z-axis

src/Cameras/arcRotateCamera.ts

@@ -885,20 +885,11 @@ export class ArcRotateCamera extends TargetCamera {
 
         // Panning inertia
         if (this.inertialPanningX !== 0 || this.inertialPanningY !== 0) {
-            this._viewMatrix.invertToRef(this._cameraTransformMatrix);
-            this._transformedDirection.set(this._cameraTransformMatrix.m[0], this._cameraTransformMatrix.m[1], this._cameraTransformMatrix.m[2]);
-
-            // panning on X Axis
-            this._transformedDirection.x *= this.panningAxis.x * this.inertialPanningX;
-            this._transformedDirection.y *= this.panningAxis.x * this.inertialPanningX;
-            this._transformedDirection.z *= this.panningAxis.x * this.inertialPanningX;
+            let localDirection = new Vector3(this.inertialPanningX, this.inertialPanningY, this.inertialPanningY);
 
-            // panning on Y axis
-            this._transformedDirection.y += this.panningAxis.y * this.inertialPanningY;
-
-            // panning on Z axis
-            this._transformedDirection.x -= Math.cos(this.alpha) * this.panningAxis.z * this.inertialPanningY;
-            this._transformedDirection.z -= Math.sin(this.alpha) * this.panningAxis.z * this.inertialPanningY;
+            this._viewMatrix.invertToRef(this._cameraTransformMatrix);
+            localDirection.multiplyInPlace(this.panningAxis);
+            Vector3.TransformNormalToRef(localDirection, this._cameraTransformMatrix, this._transformedDirection);
 
             if (!this._targetHost) {
                 if (this.panningDistanceLimit) {