text: //
  // Copyright (c) 2008-2018 the Urho3D project.
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall be included in
  // all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  // THE SOFTWARE.
  //
  
  #pragma once
  
  #include <Urho3D/Input/Controls.h>
  #include <Urho3D/Physics/PhysicsUtils.h>
  #include <Urho3D/Scene/LogicComponent.h>
  
  namespace Urho3D
  {
      class Constraint;
      class Node;
      class RigidBody;
  }
  
  using namespace Urho3D;
  
  const unsigned CTRL_FORWARD = (1u << 0u);
  const unsigned CTRL_BACK = (1u << 1u);
  const unsigned CTRL_LEFT = (1u << 2u);
  const unsigned CTRL_RIGHT = (1u << 3u);
  const unsigned CTRL_BRAKE = (1u << 4u);
  const float YAW_SENSITIVITY = 0.1f;
  const float ENGINE_POWER = 150.0f;
  const float MAX_WHEEL_ANGLE = 22.5f;
  
  // Vehicle component, responsible for physical movement according to controls.
  // Encapsulates RaycastVehicle
  class Vehicle : public LogicComponent
  {
      URHO3D_OBJECT(Vehicle, LogicComponent)
  
  public :
      /// Construct.
      explicit Vehicle(Context* context);
      /// Destruct.
      ~Vehicle() override;
  
      /// Register object factory and attributes.
      static void RegisterObject(Context* context);
  
      /// Perform post-load after deserialization. Acquire the components from the scene nodes.
      void ApplyAttributes() override;
  
      /// Initialize the vehicle. Create rendering and physics components. Called by the application.
      void Init();
  
      /// Handle physics world update. Called by LogicComponent base class.
      void FixedUpdate(float timeStep) override;
      /// Updating wheel effects here.
      void PostUpdate(float timeStep) override;
  
      /// Movement controls.
      Controls controls_;
  
      /// Get steering value.
      float GetSteering() { return steering_; }
  
      /// Set steering value.
      void SetSteering(float steering) { steering_ = steering; }
  
      /// Get wheel radius.
      float GetWheelRadius() { return wheelRadius_; }
  
      /// Get wheel width.
      float GetWheelWidth() { return wheelWidth_; }
  
  private:
      /// Creates particle emitter.
      void CreateEmitter(Vector3 place);
  
      /// Current left/right steering amount (-1 to 1.)
      float steering_;
      /// Tmp storage for steering
      float vehicleSteering_;
      /// Linear momentum supplied by engine to RigidBody
      float engineForce_;
      /// Rotational momentum preventing (dampening) wheels rotation
      float brakingForce_;
      /// Maximum linear momentum supplied by engine to RigidBody
      float maxEngineForce_;
      /// Stored wheel radius
      float wheelRadius_;
      /// Suspension rest length (in meters)
      float suspensionRestLength_;
      /// Width of wheel (used only in calculation of wheel placement)
      float wheelWidth_;
      /// Suspension stiffness
      float suspensionStiffness_;
      /// Suspension damping
      float suspensionDamping_;
      /// Suspension compression
      float suspensionCompression_;
      /// Wheel friction
      float wheelFriction_;
      /// Wheel roll influence (how much car will turn sidewise)
      float rollInfluence_;
      /// Emitter data for saving.
      Vector<Node*> particleEmitterNodeList_;
      /// Value to calculate acceleration.
      Vector3 prevVelocity_;
      /// Storing points for emitters
      Vector3 connectionPoints_[4];
      /// Do not recreate emitters if they are already created.
      bool emittersCreated;
  };
  