On Windows, there are several APIs to process input from the user from the keyboard, mouse, and controllers.

To obtain input from the keyboard and mouse:

• Window Messages
• Win32 Functions
• Raw Input
• DirectInput

To obtain input from controllers:

• Raw Input
• DirectInput
• XInput

Keyboard Window Messages

When the user presses or releases a key when a window has keyboard focus, the window receives the WM_KEYDOWN and WM_KEYUP messages.

The wParam contains the virtual-key code of the key (VK constants).

We can handle each key with a switch statement.

case WM_KEYDOWN:
		switch (wParam)
		{
		    // Handle pressed keys
		    // ...		
		}
		return 0;

case WM_KEYUP:
		switch (wParam)
		{
		    // Handle released keys
		    // ...
    }
    return 0;

For example, we handle the Escape key and terminate the application.

case VK_ESCAPE:
		PostQuitMessage(0);
    break;

To be able to handle the event outside of the window procedure, we can:

• Invoke a callback with the key code.
• Push the event to a custom event queue.