doc: update camera_manipulation example project and docs

docs/camera_manipulation.mdx

@@ -16,14 +16,48 @@ This will generally wrap a `ThermionWidget`, meaning the entire viewport will ac
         Positioned.fill(
             child: ThermionListenerWidget(
                 inputHandler:
-                    DelegateInputHandler.fixedOrbit(_thermionViewer!),
+                    DelegateInputHandler.fixedOrbit(_thermionViewer!)
+                    ..setActionForType(InputType.MMB_HOLD_AND_MOVE, InputAction.ROTATE)
+                    ..setActionForType(InputType.SCALE1, InputAction.ROTATE)
+                    ..setActionForType(InputType.SCALE2, InputAction.ZOOM)
+                    ..setActionForType(InputType.SCROLLWHEEL, InputAction.ZOOM),
                 child: ThermionWidget(
                   viewer: _thermionViewer!,
                 ))),
     ]);
 ```
 
-`ThermionListenerWidget` is a very simple widget; it simply forwards pointer, gesture and keyboard events to an instance of [InputHandler] that you provide.
+`ThermionListenerWidget` is a very simple widget; it simply forwards pointer, gesture and keyboard events to the provided [InputHandler], which must decide how to interpret those events.
+
+For example, one [InputHandler] implementation might interpret mouse pointer movement as "rotate the camera", whereas a separate implementation might interpret it as "translate this specific entity".
+
+Thermion provides two default InputHandler implementations for manipulating the camera: [DelegateInputHandler.fixedOrbit] and [DelegateInputHandler.flight].
+
+[DelegateInputHandler.fixedOrbit] will rotate the camera in a fixed orbit around a target point (the origin, by default), and also allow zooming in/out (subject to a minimum distance, which is configurable).
+
+By default, [DelegateInputHandler.fixedOrbit] will:
+- rotate the camera when the middle mouse button is held and the pointer is moved (on desktop), and when a single swipe left/right/up/down is detected (on mobile)
+- zoom the camera when the scroll wheel is scrolled up/down (on desktop), and when a pinch gesture is detected (on mobile)
+
+You can change the action for a specific input type by calling `setActionForType`; for example, if you wanted to rotate the camera by moving the mouse pointer while holding the left mouse button, you would call:
+
+```
+setActionForType(InputType.LMB_HOLD_AND_MOVE, InputAction.ROTATE)
+```
+
+See the [InputType] and [InputAction] enums for available input types and actions.
+
+[DelegateInputHandler.flight] will translate keyboard and mouse/touchscreen gestures to free flight camera manipulation. 
+
+By default:
+- holding the middle mouse button will control the pitch/roll/yaw of the camera
+- holding the left mouse button will pan the camera left/right/up/down
+- the middle mouse button will zoom/dolly the camera in/out
+- the WASD keys will pan the camera left/right/up/down and dolly the camera forward/backward
+
+If these don't exactly fit your use case, you can create your own [InputHandler] implementation. If you think it would be useful to other users, please feel free to submit a PR for your implementation to be included in the base Thermion package.
+
+
 
 
 

examples/flutter/camera_manipulation/lib/main.dart

@@ -36,6 +36,9 @@ class MyHomePage extends StatefulWidget {
 
 class _MyHomePageState extends State<MyHomePage> {
   
+  late DelegateInputHandler _fixedOrbitInputHandler;
+  late DelegateInputHandler _freeFlightInputHandler;
+  
   @override
   void initState() {
     super.initState();
@@ -48,27 +51,51 @@ class _MyHomePageState extends State<MyHomePage> {
       await _thermionViewer!.setPostProcessing(true);
       await _thermionViewer!.setRendering(true);
 
+      _fixedOrbitInputHandler =
+          DelegateInputHandler.fixedOrbit(_thermionViewer!)
+            ..setActionForType(InputType.MMB_HOLD_AND_MOVE, InputAction.ROTATE)
+            ..setActionForType(InputType.SCALE1, InputAction.ROTATE)
+            ..setActionForType(InputType.SCALE2, InputAction.ZOOM)
+            ..setActionForType(InputType.SCROLLWHEEL, InputAction.ZOOM);
+
+      _freeFlightInputHandler =
+          DelegateInputHandler.flight(_thermionViewer!)
+            ..setActionForType(InputType.MMB_HOLD_AND_MOVE, InputAction.ROTATE)
+            ..setActionForType(InputType.SCALE1, InputAction.ROTATE)
+            ..setActionForType(InputType.SCALE2, InputAction.ZOOM)
+            ..setActionForType(InputType.SCROLLWHEEL, InputAction.ZOOM);
+
       setState(() {});
     });
   }
 
   ThermionViewer? _thermionViewer;
 
+  bool isOrbit = true;
+
   @override
   Widget build(BuildContext context) {
     return Stack(children: [
-      if (_thermionViewer != null)
+      if (_thermionViewer != null) ...[
         Positioned.fill(
             child: ThermionListenerWidget(
-                inputHandler:
+                inputHandler: isOrbit
-                    DelegateInputHandler.fixedOrbit(_thermionViewer!)
+                    ? _fixedOrbitInputHandler : _freeFlightInputHandler,
-                      ..setActionForType(InputType.MMB_HOLD_AND_MOVE, InputAction.ROTATE)
+                    child:ThermionWidget(
-                      ..setActionForType(InputType.SCALE1, InputAction.ROTATE)
+                        viewer: _thermionViewer!,
-                      ..setActionForType(InputType.SCALE2, InputAction.ZOOM)
+                      ))),
-                      ..setActionForType(InputType.SCROLLWHEEL, InputAction.ZOOM)       ,
+        Column(
-                child: ThermionWidget(
+          mainAxisAlignment: MainAxisAlignment.end,
-                  viewer: _thermionViewer!,
+          children: [
-                ))),
+            ElevatedButton(
+                onPressed: () {
+                  isOrbit = !isOrbit;
+                  setState(() {});
+                },
+                child: Text("Switch to ${isOrbit ? "Free Flight" : "Orbit"}"))
+          ],
+        )
+      ],
     ]);
   }
 }