[sim] Add joystick simulation support (#2595)

This adds joystick functions to DriverStationSim, and new GenericHIDSim,
JoystickSim, and XboxControllerSim classes.

wpilibc/src/main/native/include/frc/simulation/GenericHIDSim.h

@@ -0,0 +1,97 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2020 FIRST. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#pragma once
+
+#include "frc/GenericHID.h"
+#include "frc/simulation/DriverStationSim.h"
+
+namespace frc {
+namespace sim {
+
+/**
+ * Class to control a simulated generic joystick.
+ */
+class GenericHIDSim {
+ public:
+  /**
+   * Constructs from a GenericHID object.
+   *
+   * @param joystick joystick to simulate
+   */
+  explicit GenericHIDSim(const GenericHID& joystick)
+      : m_port{joystick.GetPort()} {}
+
+  /**
+   * Constructs from a joystick port number.
+   *
+   * @param port port number
+   */
+  explicit GenericHIDSim(int port) : m_port{port} {}
+
+  /**
+   * Updates joystick data so that new values are visible to the user program.
+   */
+  void NotifyNewData() { DriverStationSim::NotifyNewData(); }
+
+  void SetRawButton(int button, bool value) {
+    DriverStationSim::SetJoystickButton(m_port, button, value);
+  }
+
+  void SetRawAxis(int axis, double value) {
+    DriverStationSim::SetJoystickAxis(m_port, axis, value);
+  }
+
+  void SetPOV(int pov, int value) {
+    DriverStationSim::SetJoystickPOV(m_port, pov, value);
+  }
+
+  void SetPOV(int value) { SetPOV(0, value); }
+
+  void SetAxisCount(int count) {
+    DriverStationSim::SetJoystickAxisCount(m_port, count);
+  }
+
+  void SetPOVCount(int count) {
+    DriverStationSim::SetJoystickPOVCount(m_port, count);
+  }
+
+  void SetButtonCount(int count) {
+    DriverStationSim::SetJoystickButtonCount(m_port, count);
+  }
+
+  void SetType(GenericHID::HIDType type) {
+    DriverStationSim::SetJoystickType(m_port, type);
+  }
+
+  void SetName(const char* name) {
+    DriverStationSim::SetJoystickName(m_port, name);
+  }
+
+  void SetAxisType(int axis, int type) {
+    DriverStationSim::SetJoystickAxisType(m_port, axis, type);
+  }
+
+  bool GetOutput(int outputNumber) {
+    int64_t outputs = GetOutputs();
+    return (outputs & (static_cast<int64_t>(1) << (outputNumber - 1))) != 0;
+  }
+
+  int64_t GetOutputs() { return DriverStationSim::GetJoystickOutputs(m_port); }
+
+  double GetRumble(GenericHID::RumbleType type) {
+    int value = DriverStationSim::GetJoystickRumble(
+        m_port, type == GenericHID::kLeftRumble ? 0 : 1);
+    return value / 65535.0;
+  }
+
+ protected:
+  int m_port;
+};
+
+}  // namespace sim
+}  // namespace frc