Overview

Create a main window for a game

In the previous tutorial, we have create a main window for a standard Windows application.

Now, we will make some changes to create a main window that can be used for a game view.

Steps

• Specify a width and height for the window
• Adjust the the window size based on the desired game view size
• Process messages without blocking the main thread
• Handle additional messages

We define a structure called WindowDescriptor that contains the information needed to create the game window.

The structure contains:

• Title – The title of the window
• Width and Height – The size of the window
• MinWidth and MinHeight – The minimum size of the window (or 0 if unbounded)

Window Size

When we call the CreateWindowEx function, we can replace the window title and the CW_USEDEFAULT constant with values from the WindowDescriptor structure.

HWND hWnd = CreateWindowEx(
    WS_EX_OVERLAPPEDWINDOW,
    wc.lpszClassName,
    **WindowDescriptor.Title.c_str()**,
    WS_OVERLAPPEDWINDOW,
    CW_USEDEFAULT,
    CW_USEDEFAULT,
    **WindowDescriptor.Width**,
    **WindowDescriptor.Height**,
    nullptr,
    nullptr,
    hInstance,
    nullptr);

The previous sample code creates a window that matches the specified window size.

However, the window contains a title bar and a border that reduce the client size of the window.

The Windows API distinguishes the client area and the nonclient area of a window. The client area is the rectangle where the game will be presented, and the nonclient area is the rectangle that includes the title bar, border, and other elements such as a menu menu if any is present.