1 files changed, 37 insertions, 5 deletions
diff --git a/src/SomhairlesDream.Frontend/App.fs b/src/SomhairlesDream.Frontend/App.fs
index ec9e273..e6edd51 100644
--- a/src/SomhairlesDream.Frontend/App.fs
+++ b/src/SomhairlesDream.Frontend/App.fs
@@ -47,7 +47,14 @@ type ViewState =
       Scene: ThreeNode
       Camera: ThreeCamera
       Group: ThreeNode
-      Canvas: HTMLCanvasElement }
+      Canvas: HTMLCanvasElement
+      Controls: obj }
+
+// Auto-spin pauses while the visitor is dragging or zooming the model and
+// resumes a few seconds after the last interaction, so inspecting a stage
+// (dish, RTG, mast) is never fought by the idle animation.
+let mutable lastInteractionMs = 0.0
+let idleSpinDelayMs = 3500.0
 
 type LoadOwner =
     { ProjectId: string
@@ -199,6 +206,14 @@ let frameObject (view: ViewState) (node: ThreeNode) =
             camera.lookAt(0.0, 0.0, 0.0)
             camera.updateProjectionMatrix ()
 
+            // Re-sync the orbit target after every auto-fit so drag/zoom
+            // pivots around the freshly centered model.
+            match view.Controls with
+            | null -> ()
+            | controls ->
+                setControlsTarget controls 0.0 0.0 0.0
+                updateControls controls
+
 let resizeView (view: ViewState) =
     let width = max 1.0 (float view.Canvas.clientWidth)
     let height = max 1.0 (float view.Canvas.clientHeight)
@@ -230,7 +245,7 @@ let initializeView () =
     scene.background <- createColor("#11171a")
     let camera = createPerspectiveCamera(34.0, width / height, 0.1, 100.0)
     camera.position.set(6.4, 4.6, 7.2) |> ignore
-    camera.lookAt(0.0, 1.2, 0.0)
+    camera.lookAt(0.0, 0.0, 0.0)
     let group = createGroup()
     scene.add(group)
     scene.add(createAmbientLight("#f0e6c8", 1.9))
@@ -238,23 +253,40 @@ let initializeView () =
     keyLight.position.set(4.0, 7.0, 5.0) |> ignore
     scene.add(keyLight)
 
+    let controls = createOrbitControls camera canvas
+    setControlsTarget controls 0.0 0.0 0.0
+    setControlsDamping controls true
+    setControlsAutoRotateSpeed controls 0.7
+
     let view =
         { Renderer = renderer
           Scene = scene
           Camera = camera
           Group = group
-          Canvas = canvas }
+          Canvas = canvas
+          Controls = controls }
 
     viewState <- Some view
+
     freezeRotation <- (queryParam "freeze") = "1"
-    exposeViewerDebug camera scene group canvas
+    setControlsAutoRotate controls (not freezeRotation)
+    exposeViewerDebug camera scene group canvas controls
     renderFrame selectedFrame
     window.addEventListener("resize", fun _ -> resizeView view)
 
-    let rec animate (_: float) =
+    canvas.addEventListener("pointerdown", fun _ -> lastInteractionMs <- JS.Constructors.Date.now ())
+    canvas.addEventListener("wheel", fun _ -> lastInteractionMs <- JS.Constructors.Date.now ())
+    canvas.addEventListener("touchstart", fun _ -> lastInteractionMs <- JS.Constructors.Date.now ())
+
+    let rec animate (nowMs: float) =
+        updateControls controls
+
         if not freezeRotation then
             group.rotation.y <- group.rotation.y + 0.003
 
+        let interacting = nowMs - lastInteractionMs < idleSpinDelayMs
+        setControlsAutoRotate controls (not freezeRotation && not interacting)
+
         renderer.render(scene, camera)
         requestAnimationFrame animate |> ignore