Add ESP32 Serial support to SwiftyCar

SwiftyCar/Sources/SwiftyCar/VehicleFactory.swift

@@ -8,16 +8,31 @@
 import Foundation
 import SwiftyGPIO
 import Swift2dCar
+import SwiftSerial
 
-func getVehicle2D() throws -> Vehicle2D {
+func getVehicle2D() throws -> Vehicle2D? {
+    // TODO: Clean up this factory, or see if we can get dependency injection working.
     if let value = ProcessInfo.processInfo.environment["CAR_VEHICLE"] {
         switch value{
-        case "CAR_2D":
+        case "VEHICLE_2D":
             // Get car for rpi.
             let pwms = SwiftyGPIO.hardwarePWMs(for:.RaspberryPi3)!
-            
-            // Read the feature database.
             return try RPiVehicle2D(withThrottlePin: PWMHardwareServo(forPin: (pwms[0]?[.P18])!)!, withSteeringPin:PWMHardwareServo(forPin: (pwms[1]?[.P19])!)!)
+        case "VEHICLE_SERIAL":
+            // TODO: Get from environment variable. tty won't work in macos anyway.
+            // We share the serialport object, as cu will block on macOS (required by SwiftSerial), so can't open 2 of the same port.
+            let serialPort = SerialPort(path: "/dev/ttyUSB0")
+            guard let throttlePin = Esp32ServoOutput(forChannel: 1, forPin: 14, onPort: serialPort) else {
+                print("Failed to create throttle pin.")
+                return nil
+            }
+
+            guard let steeringPin = Esp32ServoOutput(forChannel: 2, forPin: 12, onPort: serialPort) else {
+                print("Failed to create steering pin.")
+                return nil
+            }
+
+            return try RPiVehicle2D(withThrottlePin: PWMHardwareServo(forPin: throttlePin)!, withSteeringPin: PWMHardwareServo(forPin: steeringPin)!)
         default:
             return MockVehicle()
         }

SwiftyCar/Sources/SwiftyCar/main.swift

@@ -24,7 +24,7 @@ func doServer() throws {
         return false
     }
     // Create a provider using the features we read.
-    let provider = try MotorProvider(vehicle: getVehicle2D())
+    let provider = try MotorProvider(vehicle: getVehicle2D()!)
     let trackingProvider = LidarProvider(lidar: lidar)
 
     // Start the server and print its address once it has started.