feat(sandbox): Added top menu with control buttons

sandbox/lib/main.dart

@@ -4,12 +4,28 @@ import 'presets.dart';
 import 'scene.dart';
 import 'widgets/left_menu.dart';
 import 'widgets/scene_widget.dart';
+import 'widgets/top_menu.dart';
 
 void main() {
   runApp(
     MaterialApp(
       title: 'Radiance sandbox',
-      theme: ThemeData.dark(),
+      theme: ThemeData(
+        brightness: Brightness.dark,
+        textButtonTheme: TextButtonThemeData(
+          style: ButtonStyle(
+            minimumSize: MaterialStateProperty.all(const Size(30, 30)),
+            padding: MaterialStateProperty.all(const EdgeInsets.all(5)),
+            foregroundColor: MaterialStateProperty.resolveWith<Color>(
+              (Set<MaterialState> states) =>
+                  states.contains(MaterialState.disabled)
+                      ? const Color(0xFF5F5F5F)
+                      : const Color(0xFFBBBBBB),
+            ),
+            overlayColor: MaterialStateProperty.all(const Color(0xFF555555)),
+          ),
+        ),
+      ),
       home: const _MyApp(),
     ),
   );
@@ -23,8 +39,28 @@ class _MyApp extends StatefulWidget {
 }
 
 class SandboxState extends State<_MyApp> {
+  SandboxState() {
+    currentScene = kPresets[currentPreset]();
+  }
+
   int currentPreset = 0;
-  Scene get currentScene => kPresets[currentPreset];
+  EngineState engineState = EngineState.running;
+  late Scene currentScene;
+
+  void startEngine() {
+    setState(() => engineState = EngineState.running);
+  }
+
+  void pauseEngine() {
+    setState(() => engineState = EngineState.paused);
+  }
+
+  void stopEngine() {
+    setState(() {
+      engineState = EngineState.stopped;
+      currentScene = kPresets[currentPreset]();
+    });
+  }
 
   @override
   Widget build(BuildContext context) {
@@ -49,6 +85,7 @@ class SandboxState extends State<_MyApp> {
                   Container(
                     constraints: const BoxConstraints.expand(height: 40),
                     color: Theme.of(context).cardColor,
+                    child: TopMenu(this),
                   ),
                   // Main canvas area
                   Expanded(
@@ -81,3 +118,9 @@ class SandboxState extends State<_MyApp> {
     );
   }
 }
+
+enum EngineState {
+  running,
+  paused,
+  stopped,
+}

sandbox/lib/presets.dart

@@ -5,8 +5,8 @@ import 'entities/max_acceleration_entity.dart';
 import 'entities/static_target_entity.dart';
 import 'scene.dart';
 
-final kPresets = <Scene>[
-  _seek(),
+final kPresets = [
+  _seek,
 ];
 
 Scene _seek() {

sandbox/lib/widgets/left_menu.dart

@@ -74,7 +74,7 @@ class _ListItemState extends State<_ListItem> {
           child: Padding(
             padding: const EdgeInsets.symmetric(vertical: 2, horizontal: 4),
             child: Text(
-              kPresets[widget.index].name,
+              widget.app.currentScene.name,
               style: isCurrent ? styleWhenCurrent : null,
             ),
           ),

sandbox/lib/widgets/scene_widget.dart

@@ -16,6 +16,7 @@ class SceneWidget extends StatefulWidget {
 class _SceneWidgetState extends State<SceneWidget> {
   Ticker? ticker;
   Duration currentTime = Duration.zero;
+  EngineState currentState = EngineState.running;
   double dt = 0.0;
 
   void _handleTick(Duration time) {
@@ -26,6 +27,16 @@ class _SceneWidgetState extends State<SceneWidget> {
     });
   }
 
+  void _handleStateChange() {
+    if (widget.app.engineState == EngineState.running) {
+      ticker?.start();
+    } else {
+      ticker?.stop();
+      currentTime = Duration.zero;
+    }
+    currentState = widget.app.engineState;
+  }
+
   @override
   void initState() {
     super.initState();
@@ -40,6 +51,9 @@ class _SceneWidgetState extends State<SceneWidget> {
 
   @override
   Widget build(BuildContext context) {
+    if (currentState != widget.app.engineState) {
+      _handleStateChange();
+    }
     return Align(
       child: AspectRatio(
         aspectRatio: 100 / 80,

sandbox/lib/widgets/top_menu.dart

@@ -0,0 +1,34 @@
+import 'package:flutter/material.dart';
+import '../main.dart';
+
+class TopMenu extends StatelessWidget {
+  const TopMenu(this.app);
+
+  final SandboxState app;
+
+  @override
+  Widget build(BuildContext context) {
+    final canPause = app.engineState == EngineState.running;
+    final canStop = app.engineState != EngineState.stopped;
+    return Padding(
+      padding: const EdgeInsets.symmetric(vertical: 3, horizontal: 10),
+      child: Row(
+        children: [
+          TextButton(
+            onPressed: canPause ? _handlePause : _handleStart,
+            child:
+                Icon(canPause ? Icons.pause_rounded : Icons.play_arrow_rounded),
+          ),
+          TextButton(
+            onPressed: canStop ? _handleStop : null,
+            child: const Icon(Icons.stop_rounded),
+          ),
+        ],
+      ),
+    );
+  }
+
+  void _handleStart() => app.startEngine();
+  void _handlePause() => app.pauseEngine();
+  void _handleStop() => app.stopEngine();
+}