Initialisation: set in the pixel format attributes when the rendering context is created

glClearColor(0.5f, 0.5f, 0.5f, 1);    // Set the background colour

Game::Render() method:

glClear (GL_COLOR_BUFFER_BIT);   // Clear the back colour buffer

// Draw the scene
SwapBuffers(m_gameWindow.Hdc());   // Swap buffers

High