为什么对CreateWindow的调用失败,我该如何解决？

Question

我正在关注directx12的教程,甚至无法克服窗口D的创建:有一个实现的错误窗口,它告诉我在创建实际想要创建的窗口时出错.这应该意味着它"没有成功获得一个窗口句柄"......我没有任何东西可以说明这意味着什么,但我会非常感谢一些帮助.

#include "stdafx.h"

//Handle to the window
HWND hwnd = NULL;

//Name of the window
LPCTSTR WindowName = L"GameEngineApp";

//Title of the window
LPCTSTR WindowTitle = L"My Game Engine";

//Width and height of the window
int Width = 800;
int Height = 600;

//Toggle for fool screen
bool FullScreen = false;

//Toggle for window creation
bool InitializeWindow(HINSTANCE hInstance,
    int ShowWnd, int width, int height, bool fullscreen);

//Main application loop
void mainLoop()
{
    //The message var hold any windows message received through the 
    //PeekMessage function
    MSG msg;
    ZeroMemory(&msg, sizeof(MSG));

    while (true)
    {
        if (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
        {
            //If there is a message, it is translated
            //then dispatched so Windows 
            //knows the program hasn't stopped working
            if (msg.message = WM_QUIT) {
                break;

                TranslateMessage(&msg);
                DispatchMessage(&msg);
            }
            else {
                //If there is no message the game 
                //code will run and the loop will continue
            }
        }
    }
}

//Callback function for windows messages
LRESULT CALLBACK WndProc(HWND hWnd,
    UINT msg, WPARAM wParam, LPARAM lParam)
{
    switch (msg)
    {
    case WM_KEYDOWN:
        if (wParam == VK_ESCAPE) {
            if (MessageBox(0, L"Are you sure you want to exit?",
                L"Really?", MB_YESNO | MB_ICONQUESTION) == IDYES)
                DestroyWindow(hwnd);
        }
        return 0;

    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }
    return DefWindowProc(hwnd,
        msg, wParam, lParam);
}

//Main Windows function
int WINAPI WinMain(HINSTANCE hInstance,
    HINSTANCE hPrevInstance,
    LPSTR lpCmdLine,
    int nShowCmd)
{
    //Toggle window creation
    if (!InitializeWindow(hInstance, nShowCmd, Width, Height, FullScreen))
    {
        MessageBox(0, L"Window Initialization - Failed",
            L"Error", MB_OK);
        return 0;
    }

    mainLoop(); //Call main loop to start

    return 0;
}

bool InitializeWindow(HINSTANCE hInstance,
    int ShowWnd, int width, int height, bool fullscreen)
{
    //Check if fullscreen is needed and set to fullscreen if so
    if (fullscreen)
    {
        HMONITOR hmon = MonitorFromWindow(hwnd,
            MONITOR_DEFAULTTONEAREST);
        MONITORINFO mi = { sizeof(mi) };
        GetMonitorInfo(hmon, &mi);

        width = mi.rcMonitor.right - mi.rcMonitor.left;
        height = mi.rcMonitor.bottom - mi.rcMonitor.top;
    }

    //Window class structure
    WNDCLASSEX wc;
    wc.cbSize = sizeof(WNDCLASSEX);
    wc.style = CS_HREDRAW | CS_VREDRAW;
    wc.lpfnWndProc = WndProc;
    wc.cbClsExtra = NULL;
    wc.cbWndExtra = NULL;
    wc.hInstance = hInstance;
    wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);
    wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 2);
    wc.lpszMenuName = NULL;
    wc.lpszClassName = WindowName;
    wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);

    //Registering the window class
    if (!RegisterClassEx(&wc))
    {
        MessageBox(NULL, L"Error registering class",
            L"Error", MB_OK | MB_ICONERROR);
        return false;
    }

    //Create the window with the now registered window class
    hwnd = CreateWindowEx(NULL,
        WindowName,
        WindowTitle,
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT,
        width, height,
        NULL,
        NULL,
        hInstance,
        NULL);

    //Return error msg if unsuccessful in getting a window handle
    if (!hwnd)
    {
        MessageBox(NULL, L"Error creating window",
            L"Error", MB_OK | MB_ICONERROR);
        return false;
    }

    //Removing the style from the window when fullscreen
    if (fullscreen)
    {
        SetWindowLong(hwnd, GWL_STYLE, 0);
    }

    //Showing and updating the window
    ShowWindow(hwnd, ShowWnd);
    UpdateWindow(hwnd);

    return true;
}

我试图将CreateWIndowEx更改为CreateWindowA,这真的是唯一似乎可能产生影响但我没有看到任何结果的东西.我已经尝试打印错误,但没有错误.

使用C++代码在Windows中创建一个窗口,这样我就可以创建一个游戏引擎.

Answer 1

虽然不会滥用全局变量.

你正在调用DefWndProc你的WndProcwith hwnd作为句柄参数.但是直到返回时才会设置CreateWindowEx,并且在窗口站立期间有很多非常重要的消息被掠过WndProc.这些消息需要窗口句柄,而你不会传递它.相反,你只是传递NULL(启动值hwnd).

将全部 更改hwnd为hWnd(参数名称)WndProc

我留给您解决的评论中提到的其余问题.