Open Engine.h, add an include for our new class, declare an instance of the new HUD class, and also declare and initialize two new member variables that will keep track of how often we update the HUD. As we have learned in the two previous projects, we don't need to do this for every frame.

Add the highlighted code to Engine.h:

#pragma once 
#include <SFML/Graphics.hpp> 
#include "TextureHolder.h" 
#include "Thomas.h" 
#include "Bob.h" 
#include "LevelManager.h" 
#include "SoundManager.h" 
#include "HUD.h" 
 
using namespace sf; 
 
class Engine 
{ 
private: 
   // The texture holder 
   TextureHolder th; 
 
   // Thomas and his friend, Bob 
   Thomas m_Thomas; 
   Bob m_Bob; 
 
   // A class to manage all the levels 
   LevelManager m_LM; 
 
   // Create a SoundManager 
   SoundManager m_SM; 
 
   // The Hud   Hud m_Hud;
   int m_FramesSinceLastHUDUpdate = 0;
   int m_TargetFramesPerHUDUpdate = 500; 
 
   const int TILE_SIZE = 50; 

Next, we need to add some code to the update function of the Engine class. Open Update.cpp and add the highlighted code to update the HUD once every 500 frames:

   // Set the appropriate view around the appropriate character 
   if (m_SplitScreen) 
   { 
      m_LeftView.setCenter(m_Thomas.getCenter()); 
      m_RightView.setCenter(m_Bob.getCenter()); 
   } 
   else 
   { 
      // Centre full screen around appropriate character 
      if (m_Character1) 
      { 
         m_MainView.setCenter(m_Thomas.getCenter()); 
      } 
      else 
      { 
         m_MainView.setCenter(m_Bob.getCenter()); 
      } 
   } 
 
   // Time to update the HUD?
   // Increment the number of frames since the last HUD calculation
   m_FramesSinceLastHUDUpdate++;

   // Update the HUD every m_TargetFramesPerHUDUpdate frames
   if (m_FramesSinceLastHUDUpdate > m_TargetFramesPerHUDUpdate)
   {
     // Update game HUD text
     stringstream ssTime;
     stringstream ssLevel; 
     // Update the time text 
     ssTime << (int)m_TimeRemaining;
     m_Hud.setTime(ssTime.str());
     // Update the level text
     ssLevel << "Level:" << m_LM.getCurrentLevel();
     m_Hud.setLevel(ssLevel.str());
     m_FramesSinceLastHUDUpdate = 0;
   } 
}// End of update function 

In the previous code, m_FramesSinceLastUpdate is incremented each frame. When m_FramesSinceLastUpdate exceeds m_TargetFramesPerHUDUpdate, execution enters the if block. Inside the if block, we use stringstream objects to update our Text, as we have done in both previous projects. As you probably expected, however, in this project we are using the HUD class, so we call the setTime and setLevel functions, passing in the current values that the Text objects need to be set to.

The final step in the if block is to set m_FramesSinceLastUpdate back to zero so it can start counting toward the next update.

Finally, open the Draw.cpp file and add the highlighted code to draw the HUD, each frame:

   else 
   { 
      // Split-screen view is active 
 
      // First draw Thomas' side of the screen 
 
      // Switch to background view 
      m_Window.setView(m_BGLeftView); 
      // Draw the background 
      m_Window.draw(m_BackgroundSprite); 
      // Switch to m_LeftView 
      m_Window.setView(m_LeftView); 
 
      // Draw the Level 
      m_Window.draw(m_VALevel, &m_TextureTiles); 
          
      // Draw thomas 
      m_Window.draw(m_Bob.getSprite()); 
 
      // Draw thomas 
      m_Window.draw(m_Thomas.getSprite()); 
       
      // Now draw Bob's side of the screen 
 
      // Switch to background view 
      m_Window.setView(m_BGRightView); 
      // Draw the background 
      m_Window.draw(m_BackgroundSprite); 
      // Switch to m_RightView 
      m_Window.setView(m_RightView); 
 
      // Draw the Level 
      m_Window.draw(m_VALevel, &m_TextureTiles); 
 
      // Draw thomas 
      m_Window.draw(m_Thomas.getSprite()); 
 
      // Draw bob 
      m_Window.draw(m_Bob.getSprite()); 
             
   } 
 
   // Draw the HUD 
   // Switch to m_HudView 
   m_Window.setView(m_HudView); 
   m_Window.draw(m_Hud.getLevel());
   m_Window.draw(m_Hud.getTime());
   if (!m_Playing)
   {
     m_Window.draw(m_Hud.getMessage());
   } 
   // Show everything we have just drawn 
   m_Window.display(); 
}// End of draw 

The previous code draws the HUD by using the getter functions from the HUD class. Notice that the call to draw the message to that prompts the player to start is only used when the game is not currently playing (!m_Playing).

Run the game and play a few levels to see the time tick down and the levels tick up. When you get back to level one again, notice that you have 10% less time than before.