text: // Copyright (c) 2008-2022 the Urho3D project
  // License: MIT
  
  #include <Urho3D/Graphics/Graphics.h>
  #include <Urho3D/Graphics/Renderer.h>
  #include <Urho3D/Input/Controls.h>
  #include <Urho3D/Input/Input.h>
  
  #include "Character.h"
  #include "Touch.h"
  
  const float GYROSCOPE_THRESHOLD = 0.1f;
  
  Touch::Touch(Context* context, float touchSensitivity) :
      Object(context),
      touchSensitivity_(touchSensitivity),
      cameraDistance_(CAMERA_INITIAL_DIST),
      zoom_(false),
      useGyroscope_(false)
  {
  }
  
  Touch::~Touch() = default;
  
  void Touch::UpdateTouches(Controls& controls) // Called from HandleUpdate
  {
      zoom_ = false; // reset bool
  
      auto* input = GetSubsystem<Input>();
  
      // Zoom in/out
      if (input->GetNumTouches() == 2)
      {
          TouchState* touch1 = input->GetTouch(0);
          TouchState* touch2 = input->GetTouch(1);
  
          // Check for zoom pattern (touches moving in opposite directions and on empty space)
          if (!touch1->touchedElement_ && !touch2->touchedElement_ && ((touch1->delta_.y_ > 0 && touch2->delta_.y_ < 0) || (touch1->delta_.y_ < 0 && touch2->delta_.y_ > 0)))
              zoom_ = true;
          else
              zoom_ = false;
  
          if (zoom_)
          {
              int sens = 0;
              // Check for zoom direction (in/out)
              if (Abs(touch1->position_.y_ - touch2->position_.y_) > Abs(touch1->lastPosition_.y_ - touch2->lastPosition_.y_))
                  sens = -1;
              else
                  sens = 1;
              cameraDistance_ += Abs(touch1->delta_.y_ - touch2->delta_.y_) * sens * touchSensitivity_ / 50.0f;
              cameraDistance_ = Clamp(cameraDistance_, CAMERA_MIN_DIST, CAMERA_MAX_DIST); // Restrict zoom range to [1;20]
          }
      }
  
      // Gyroscope (emulated by SDL through a virtual joystick)
      if (useGyroscope_ && input->GetNumJoysticks() > 0)  // numJoysticks = 1 on iOS & Android
      {
          JoystickState* joystick = input->GetJoystickByIndex(0);
          if (joystick->GetNumAxes() >= 2)
          {
              if (joystick->GetAxisPosition(0) < -GYROSCOPE_THRESHOLD)
                  controls.Set(CTRL_LEFT, true);
              if (joystick->GetAxisPosition(0) > GYROSCOPE_THRESHOLD)
                  controls.Set(CTRL_RIGHT, true);
              if (joystick->GetAxisPosition(1) < -GYROSCOPE_THRESHOLD)
                  controls.Set(CTRL_FORWARD, true);
              if (joystick->GetAxisPosition(1) > GYROSCOPE_THRESHOLD)
                  controls.Set(CTRL_BACK, true);
          }
      }
  }
  