dinput.cpp

This tutorial will deal with getting input using Direct Input. All you will need to run and/or com

   hwnd = CreateWindowEx(NULL,// The extended window style.
                        "UltimateGameProgrammingClass",// window Class name.
                        "Direct Input tutorial - By the Programming Ace.",// window name.
                        WS_OVERLAPPEDWINDOW | WS_VISIBLE |// The window style.
                        WS_SYSMENU | WS_CLIPCHILDREN |// window style.
                        WS_CLIPSIBLINGS,// window style.
                        100, 100,// window x, y coordinate.
                        400,
                        400,// window width and height.
                        NULL,// handle to parent window.
                        NULL,// menu.
                        hInstance,// handle to app instance.
                        NULL);   // pointer to window creation data.

   // If there was an error with creating the window, then close the program.
   if(!hwnd)
      return 0;

   ShowWindow(hwnd, SW_SHOW); // This shows the window.
   UpdateWindow(hwnd);        // This forces a paint message.

   isFinished = false;        // False = running, True = not running.


   // If initialize fail (return false), then we don't want the program to run.
   if(!InitializeGL())
      isFinished = true;

   // Here is where we set up Direct Input so we can get user input from the mouse & Keyboard.
   if(!DirectInput.Initialize(hwnd, hInstance))
      return false;

   // This is the messsage loop.
   while(!isFinished)
      {
         PeekMessage(&msg, NULL, NULL, NULL, PM_REMOVE);

         if(msg.message == WM_QUIT)// If the application gets a quit message...
            {
               isFinished = true;  // Then quit the program.
            }
         else                      // else render the scene.
            {
               RenderScene();      // Render and display the next frame.

               // This will translate virtual key messages into character messages.
               TranslateMessage(&msg);
               // DispatchMessage will send a message to Windows to be processed.
               DispatchMessage(&msg);
            }
      }

   // Shutdown Direct Input.
   DirectInput.Shutdown();

   return msg.wParam;      // End the application.
}


bool InitializeGL()
{
   glClearColor(0.0f, 0.0f, 0.0f, 0.0f);  // Clear the screen to black.

   glShadeModel(GL_SMOOTH);               // Smooth shading in our scenes.
   glEnable(GL_DEPTH_TEST);               // Enable desth testing for hidden surface removal.
   glEnable(GL_LIGHTING);                 // Enable lighting.


   // Here we will set up a spotlight light source in our scene.  This light will shine on
   // the objects giving them a nicer look than a plain dull color.  This stuff has nothing
   // to do with the tutorial it self but only to make things look better.
   glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuseLight);
   glLightfv(GL_LIGHT0, GL_SPECULAR, specularLight);
   glLightfv(GL_LIGHT0, GL_POSITION, LightPosition);
   glLightf(GL_LIGHT0, GL_SPOT_CUTOFF, 10.0f);
   glLightf(GL_LIGHT0, GL_SPOT_EXPONENT, 75.0f);

   // Enable our light.
   glEnable(GL_LIGHT0);

   // Set up the material information for our objects.  Again this is just for show.
   glEnable(GL_COLOR_MATERIAL);
   glColorMaterial(GL_FRONT, GL_AMBIENT_AND_DIFFUSE);
   glMaterialfv(GL_FRONT, GL_SPECULAR, specularLight);
   glMateriali(GL_FRONT, GL_SHININESS, 128);

   // If all went well we return true.
   return true;
}


void RenderScene()
{
   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);   // Clears the screen.
   glLoadIdentity();                   //Reset modelview matrix for new frame.

   // First lets test our input objects and see if the user has pressed any key we care
   // about or has click any of the mouse buttons.
   GetInput();

   glTranslatef(0.0, 0.0, -5.0f);            // Move back 5 units.

   glRotatef(yRotation, 0.0f, 1.0f, 0.0f);   // Rotate the object along the y axis.
   glRotatef(xRotation, 1.0f, 0.0f, 0.0f);   // Rotate the object along the x axis.

   // Draw our object.  Depending on what ObjectChoice is will depend on what is drawn...
   switch(ObjectChoice)
      {
         case CUBE:
            auxSolidCube(2.0);               // Draw a solid cube.
            break;

         case SPHERE:
            auxSolidSphere(1.5);             // Draw a solid sphere.
            break;

         case TORUS:
            auxSolidTorus(0.5, 1.0);         // Draw a solid torus.
            break;

         case TEAPOT:                        // Draw a wireframe teapot.
            auxWireTeapot(1.5);
            break;

         default:                            // Reset in case neither is true.
            ObjectChoice = 0;
            break;
      }

   // Increase the rotation.
   xRotation += 0.1f;
   yRotation += 0.2f;

   // Error checking to make sure our values do not go over 360 degrees.
   if(xRotation >= 360.0f)
      xRotation = 0.0f;

   if(yRotation >= 360.0f)
      yRotation = 0.0f;

   SwapBuffers(g_HDC);                       // Display the new frame.
}


void GetInput()
{
   // First we will update all the devices our input system supports.  This will
   // check which keys are pressed and which mouse buttons are pressed.

   // We use CheckTime to only allow input to be processed only every 1/15ths of a second.
   // If .15 has passed then we allow the processing of input to continue.
   if(CheckTime(0.15))
      {
         // Update all devices.
         DirectInput.UpdateDevices();

         // Next we will check for the keys and buttons we care about.

         // Check if the user pressed the escape key.
         if(DirectInput.KeyDown(DIK_ESCAPE))
            PostQuitMessage(0);

         // Check if the user pressed the number 1 key.
         if(DirectInput.KeyDown(DIK_1))
            ObjectChoice = CUBE;

         // Check if the user pressed the number 2 key.
         if(DirectInput.KeyDown(DIK_2))
            ObjectChoice = SPHERE;

         // Check if the user pressed the number 3 key.
         if(DirectInput.KeyDown(DIK_3))
            ObjectChoice = TORUS;

         // Check if the user pressed the number 4 key.
         if(DirectInput.KeyDown(DIK_4))
            ObjectChoice = TEAPOT;

         // Check if the user pressed the left mouse button.  If so increase the ObjectChoice variable.
         if(DirectInput.MouseButtonDown(LEFT_BUTTON))
            ObjectChoice++;

         // Check if the user pressed the right mouse button.  If so decrease the ObjectChoice variable.
         if(DirectInput.MouseButtonDown(RIGHT_BUTTON))
            ObjectChoice--;
      }

   // Error checking.
   if(ObjectChoice >= 4)
      ObjectChoice = CUBE;

   if(ObjectChoice < 0)
      ObjectChoice = TEAPOT;
}


bool CheckTime(float amount)
{
   // This will be used to check if a second has passed.
   float nextSecond           = 0.0f;

   // This is the last second that occured.
   static float prevSecond	   = 0.0f;

   // Get the second in millisecond then multiply it by 0.001 to convert this to seconds.
   nextSecond = GetTickCount() * 0.001f;				

   // If amount in "amount" has passed we want to return true to the caller...
   if( nextSecond - prevSecond > amount )
      {
         // Make the second (time) we just got the previous second so we can used this the
         // next time the function is called.
	      prevSecond = nextSecond;

         return true;
      }

   // Else not enough time has passed...
   return false;
}


// Recap:

// Well there you have it.  Getting input through the keyboard and mouse using Direct Input.
// As you can see it is not that hard.  This is the better way to get input because using
// Direct Input you are accessing the hardware directly.  Another good thing about Direct Input
// is that you can easily add more devices, such as a joystick, without any complex code.
// When ever I do a tutorial dealing with input from now on I will use Direct Input.


// Copyright March 2003
// All Rights Reserved!
// Allen Sherrod
// [e-mail]
// www.UltimateGameProgramming.com