Beginning DirectX 11 Game Programming Error

Question

Here is the code that it gives me on page 33:

#include<Windows.h>

int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE prevInstance,
       LPWSTR cmdLine, int cmdShow)
{
    UNREFERENCED_PARAMETER( prevInstance );
    UNREFERENCED_PARAMETER( cmdLine );
    WNDCLASSEX wndClass = { 0 };
    wndClass.cbSize = sizeof( WNDCLASSEX ) ;
    wndClass.style = CS_HREDRAW | CS_VREDRAW;
    wndClass.lpfnWndProc = WndProc;
    wndClass.hInstance = hInstance;
    wndClass.hCursor = LoadCursor( NULL, IDC_ARROW );
    wndClass.hbrBackground = ( HBRUSH )( COLOR_WINDOW + 1 );
    wndClass.lpszMenuName = NULL;
    wndClass.lpszClassName = "DX11BookWindowClass";
    if( !RegisterClassEx( &wndClass ) )
    return -1;
    RECT rc = { 0, 0, 640, 480 };
    AdjustWindowRect( &rc, WS_OVERLAPPEDWINDOW, FALSE );
    HWND hwnd = CreateWindowA( "DX11BookWindowClass", "Blank Win32 Window",
    WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, rc.right - rc.
    left,
    rc.bottom - rc.top, NULL, NULL, hInstance, NULL );
    if( !hwnd )
    return -1;
    ShowWindow( hwnd, cmdShow );

    return 0;
}

This code gives me 2 errors-

1>------ Build started: Project: BlankWindow, Configuration: Debug Win32 ------ 1> main.cpp 1>c:\coding\c++\visual c++\directx\blankwindow\blankwindow\main.cpp(10): error C2065: 'WndProc' : undeclared identifier 1>c:\coding\c++\visual c++\directx\blankwindow\blankwindow\main.cpp(15): error C2440: '=' : cannot convert from 'const char [20]' to 'LPCWSTR' 1> Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

Basically

'WndProc' : undeclared identifier And '=' : cannot convert from 'const char [20]' to 'LPCWSTR'

What is wrong with this code?

I put the code into the question (rather than using an external link). Also, what is page 33 referring to? And where is your WndProc? Do you know what a windows procedure is? — Jesse Good
@GreyerSting: Well, since a DirectX application is by definition windowed, it would probably be a good idea to know how windows work ;) — Nicol Bolas
@GreyerSting: If you don't have a good understanding of the WinAPI and C++, you will have a very hard time with DirectX. DirectX is huge and complicated, just setting up the boilerplate code will take a few hundred lines. — Jesse Good

Jesse Good Jesse Good · Accepted Answer · 2012-07-30T23:34:27

Here is a basic working program of your code:

#include<Windows.h>

LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)
            {
                    case WM_CLOSE:
                            DestroyWindow(hwnd);
                            break;
                    case WM_DESTROY:
                            PostQuitMessage(0);
                            break;
                    default:
                            return DefWindowProc(hwnd,
                                                 message,
                                                 wParam,
                                                 lParam);
            }
    return 0;
}

int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE prevInstance,
       LPSTR cmdLine, int cmdShow)
{
    UNREFERENCED_PARAMETER( prevInstance );
    UNREFERENCED_PARAMETER( cmdLine );
    WNDCLASSEX wndClass = { 0 };
    wndClass.cbSize = sizeof( WNDCLASSEX ) ;
    wndClass.style = CS_HREDRAW | CS_VREDRAW;
    wndClass.lpfnWndProc = WndProc;
    wndClass.hInstance = hInstance;
    wndClass.hCursor = LoadCursor( NULL, IDC_ARROW );
    wndClass.hbrBackground = ( HBRUSH )( COLOR_WINDOW + 1 );
    wndClass.lpszMenuName = NULL;
    wndClass.lpszClassName = "DX11BookWindowClass";
    if( !RegisterClassEx( &wndClass ) )
    return -1;
    RECT rc = { 0, 0, 640, 480 };
    AdjustWindowRect( &rc, WS_OVERLAPPEDWINDOW, FALSE );
    HWND hwnd = CreateWindowA( L"DX11BookWindowClass", L"Blank Win32 Window",
    WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, rc.right - rc.
    left,
    rc.bottom - rc.top, NULL, NULL, hInstance, NULL );
    if( !hwnd )
    return -1;
    ShowWindow( hwnd, cmdShow );
    MSG msg;
    while (GetMessage (&msg, 0, 0, 0))
            {
                TranslateMessage (&msg);
                DispatchMessage (&msg);
            }
    return msg.wParam;
}

Points:

I added a WndProc which handles all messages sent to your program.
I added a message loop to your program. Otherwise, the window would close right away.
I added the L prefix as suggested by the_mandrill in the other answer.

This is pretty much your "Hello World" of WinAPI programming. However, I strongly suggest you learn the WinAPI first before jumping into DirectX programming.

Beginning DirectX 11 Game Programming Error

2 Answers