text: //
  // Copyright (c) 2008-2019 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 "Sample.h"
  
  namespace Urho3D
  {
  
  class Drawable;
  class Node;
  class Scene;
  
  }
  
  /// Decals example.
  /// This sample demonstrates:
  ///     - Performing a raycast to the octree and adding a decal to the hit location
  ///     - Defining a Cursor UI element which stays inside the window and can be shown/hidden
  ///     - Marking suitable (large) objects as occluders for occlusion culling
  ///     - Displaying renderer debug geometry to see the effect of occlusion
  class Decals : public Sample
  {
      URHO3D_OBJECT(Decals, Sample);
  
  public:
      /// Construct.
      explicit Decals(Context* context);
  
      /// Setup after engine initialization and before running the main loop.
      void Start() override;
  
  protected:
      /// Return XML patch instructions for screen joystick layout for a specific sample app, if any.
      String GetScreenJoystickPatchString() const override { return
          "<patch>"
          "    <remove sel=\"/element/element[./attribute[@name='Name' and @value='Button0']]/attribute[@name='Is Visible']\" />"
          "    <replace sel=\"/element/element[./attribute[@name='Name' and @value='Button0']]/element[./attribute[@name='Name' and @value='Label']]/attribute[@name='Text']/@value\">Paint</replace>"
          "    <add sel=\"/element/element[./attribute[@name='Name' and @value='Button0']]\">"
          "        <element type=\"Text\">"
          "            <attribute name=\"Name\" value=\"MouseButtonBinding\" />"
          "            <attribute name=\"Text\" value=\"LEFT\" />"
          "        </element>"
          "    </add>"
          "    <remove sel=\"/element/element[./attribute[@name='Name' and @value='Button1']]/attribute[@name='Is Visible']\" />"
          "    <replace sel=\"/element/element[./attribute[@name='Name' and @value='Button1']]/element[./attribute[@name='Name' and @value='Label']]/attribute[@name='Text']/@value\">Debug</replace>"
          "    <add sel=\"/element/element[./attribute[@name='Name' and @value='Button1']]\">"
          "        <element type=\"Text\">"
          "            <attribute name=\"Name\" value=\"KeyBinding\" />"
          "            <attribute name=\"Text\" value=\"SPACE\" />"
          "        </element>"
          "    </add>"
          "</patch>";
      }
  
  private:
      /// Construct the scene content.
      void CreateScene();
      /// Construct user interface elements.
      void CreateUI();
      /// Set up a viewport for displaying the scene.
      void SetupViewport();
      /// Subscribe to application-wide logic update and post-render update events.
      void SubscribeToEvents();
      /// Reads input and moves the camera.
      void MoveCamera(float timeStep);
      /// Paint a decal using a ray cast from the mouse cursor.
      void PaintDecal();
      /// Utility function to raycast to the cursor position. Return true if hit
      bool Raycast(float maxDistance, Vector3& hitPos, Drawable*& hitDrawable);
      /// Handle the logic update event.
      void HandleUpdate(StringHash eventType, VariantMap& eventData);
      /// Handle the post-render update event.
      void HandlePostRenderUpdate(StringHash eventType, VariantMap& eventData);
  
      /// Flag for drawing debug geometry.
      bool drawDebug_;
  };
  