// NFC_06 [FrameWindow with OpenGL].nova



// Using namespace declarations.
using Library.NFC;
using Library.OpenGL;



// The application class.
class FrameWindowWithOpenGLApp
{
   // Application class's "main" function.
   public static void main( String[] args )
   {
      // Create a new OpenGL window.
      MyGLWindow window = new MyGLWindow( "NFC_06 [FrameWindow with OpenGL]", 640, 480 );

      // Show the window.
      window.show( true );

      // Process the window's events.
      window.processEvents( );
   }
}


// Custom OpenGL window class.
class MyGLWindow : FrameWindow
{
   // The window's OpenGL rendering context.
   private RenderingContext renderingContext;


   // Class constructor.
   public MyGLWindow( String name, int sizeX, int sizeY )
      : FrameWindow( name, sizeX, sizeY )
   {
      // Create an OpenGL rendering context.
      renderingContext = OpenGL.createContext( graphics );

      // Make the new rendering context the current one.
      OpenGL.makeCurrent( graphics, renderingContext );

      // Initialize OpenGL.
      OpenGL.glShadeModel( OpenGL.GL_SMOOTH );
      OpenGL.glClearColor( 0.0f, 0.0f, 0.0f, 0.5f );
      OpenGL.glClearDepth( 1.0 );
      OpenGL.glEnable( OpenGL.GL_DEPTH_TEST );
   }


   // On paint event handler.
   public virtual void onPaint( )
   {
      // Clear the buffers.
      OpenGL.glClear( OpenGL.GL_COLOR_BUFFER_BIT | OpenGL.GL_DEPTH_BUFFER_BIT );

      // Reset the current matrix.
      OpenGL.glLoadIdentity( );

      // Move into the scene.
      OpenGL.glTranslatef( 0.0f, 0.0f, -4.0f );

      // Draw the scene.
      OpenGL.glBegin( OpenGL.GL_TRIANGLES );
      OpenGL.glColor3f(   0.0f,  0.0f, 1.0f );  // Blue.
      OpenGL.glVertex3f(  0.0f,  1.0f, 0.0f );  // Top
      OpenGL.glColor3f(   1.0f,  0.0f, 0.0f );  // Red.
      OpenGL.glVertex3f( -1.0f, -1.0f, 0.0f );  // Bottom left.
      OpenGL.glColor3f(   0.0f,  1.0f, 0.0f );  // Green.
      OpenGL.glVertex3f(  1.0f, -1.0f, 0.0f );  // Bottom right.
      OpenGL.glEnd( );

      // Swap the front and back buffers.
      OpenGL.swapBuffers( graphics );
   }


   // On size event handler.
   public virtual void onSize( int sizeX, int sizeY )
   {
      // Prevent a divide by zero error.
      if ( sizeY == 0 )
      {
         // Set the height equal to one.
         sizeY = 1;
      }

      // Reset the current viewport.
      OpenGL.glViewport( 0, 0, sizeX, sizeY );

      // Select the projection matrix.
      OpenGL.glMatrixMode( OpenGL.GL_PROJECTION );
      // Reset the projection matrix.
      OpenGL.glLoadIdentity( );

      // Calculate the aspect ratio of the window.
      OpenGL.gluPerspective( 45.0, (double)sizeX / (double)sizeY, 0.1, 100.0 );

      // Select the modelview matrix.
      OpenGL.glMatrixMode( OpenGL.GL_MODELVIEW );
      // Reset the modelview matrix.
      OpenGL.glLoadIdentity( );
   }


   // On close event handler.
   public virtual void onClose( )
   {
      // Set the current OpenGL context to null.
      OpenGL.makeCurrent( null, null );

      // Delete the OpenGL context.
      OpenGL.deleteContext( renderingContext );
   }
}