Fri Feb 25 10:33:57 AM HKT 2022

example/pspad/README.md

@@ -1,16 +1,91 @@
 # pspad
 
-A new Flutter project.
+Playstation like control pad to control turtlesim using roslibdart
 
-## Getting Started
+## How to use it
+### Start rosbridge
+```
+ros2 launch rosbridge_server rosbridge_websocket_launch.xml
+```
+### Start turtlesim in another terminal
+```
+ros2 run turtlesim turtlesim_node
+```
+### Start flutter control pad
+```
+cd pspad
+flutter run -d linux
+```
 
-This project is a starting point for a Flutter application.
+### How to use the control pad
+```
+void initState() {
+    ros = Ros(url: host);
+    cmdVelTopic = Topic(
+        ros: ros,
+        name: '/turtle1/cmd_vel',
+        type: "geometry_msgs/msg/Twist",
+        reconnectOnClose: true,
+        queueLength: 10,
+        queueSize: 10);
 
-A few resources to get you started if this is your first Flutter project:
+    ros.connect();
+    super.initState();
+    Timer.periodic(const Duration(milliseconds: 200), directionFired);
+}
+void leftCallback(int event) {
+    leftButtonState = event;
+}
+void directionFired(Timer timer) {
+    var linear = {'x': 0.0, 'y': 0.0, 'z': 0.0};
+    var angular = {'x': 0.0, 'y': 0.0, 'z': 0.0};
+    if (leftButtonState == -1) {
+      linear = {'x': 0.0, 'y': 0.0, 'z': 0.0};
+      angular = {'x': 0.0, 'y': 0.0, 'z': turnAngularVelocity};
+    } else if (rightButtonState == -1) {
+      linear = {'x': 0.0, 'y': 0.0, 'z': 0.0};
+      angular = {'x': 0.0, 'y': 0.0, 'z': -turnAngularVelocity};
+    } else if (forwardButtonState == -1) {
+      linear = {'x': forwardVelocity, 'y': 0.0, 'z': 0.0};
+      angular = {'x': 0.0, 'y': 0.0, 'z': 0};
+    } else if (backwardButtonState == -1) {
+      linear = {'x': -forwardVelocity, 'y': 0.0, 'z': 0.0};
+      angular = {'x': 0.0, 'y': 0.0, 'z': 0};
+    }
+    var twist = {'linear': linear, 'angular': angular};
+    if (lastDirectionTwist == twist &&
+        twist['linear'] == {'x': 0.0, 'y': 0.0, 'z': 0.0} &&
+        twist['angular'] == {'x': 0.0, 'y': 0.0, 'z': 0.0}) {
+      return;
+    }
 
-- [Lab: Write your first Flutter app](https://flutter.dev/docs/get-started/codelab)
-- [Cookbook: Useful Flutter samples](https://flutter.dev/docs/cookbook)
-
-For help getting started with Flutter, view our
-[online documentation](https://flutter.dev/docs), which offers tutorials,
-samples, guidance on mobile development, and a full API reference.
+    cmdVelTopic.publish(twist);
+    lastDirectionTwist = twist;
+}
+Center(
+    // Center is a layout widget. It takes a single child and positions it
+    // in the middle of the parent.
+    child: Container(
+        margin: const EdgeInsets.all(50),
+        child: Row(
+            mainAxisAlignment: MainAxisAlignment.spaceBetween,
+            children: <Widget>[
+                DirectionPad(
+                    diameter: 200,
+                    leftCallback: leftCallback,
+                    rightCallback: rightCallback,
+                    forwardCallback: forwardCallback,
+                    backwardCallback: backwardCallback,
+                ),
+                KeyPad(
+                    diameter: 200,
+                    squareCallback: squareCallback,
+                    circleCallback: circleCallback,
+                    triangleCallback: triangleCallback,
+                    crossCallback: crossCallback,
+                ),
+            ],
+        ),
+    )
+),
+```