使用 memoryDC WINAPI，仅在调整大小时更新窗口

我是WINAPI的新手，我正在尝试制作一个小游戏，我需要将图像作为一个整体显示在屏幕上，而不是依次显示每个块，我只能发现我首先需要将所有内容写入memoryDC，然后输出它，但我不明白如何完全实现它。

另外，由于某种原因，只有在调整窗口大小时才会重绘窗口，我该如何解决这个问题？

我尝试做某事：

#ifndef UNICODE
#define UNICODE
#endif 

#include <windows.h>

HBITMAP hBmp_red = (HBITMAP)LoadImage(NULL, L"C:\\Red.bmp", IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
HDC bmpdc = NULL;
HDC memdc = NULL;
HBITMAP membmp = NULL;
LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam);

int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE, PWSTR pCmdLine, int nCmdShow)
{
    // Register the window class.
    const wchar_t CLASS_NAME[] = L"Sample Window Class";

    WNDCLASS wc = { };

    wc.lpfnWndProc = WindowProc;
    wc.hInstance = hInstance;
    wc.lpszClassName = CLASS_NAME;

    RegisterClass(&wc);

    // Create the window.

    HWND hwnd = CreateWindowEx(
        0,                              // Optional window styles.
        CLASS_NAME,                     // Window class
        L"Learn to Program Windows",    // Window text
        WS_EX_APPWINDOW,            // Window style

        // Size and position
        CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,

        NULL,       // Parent window    
        NULL,       // Menu
        hInstance,  // Instance handle
        NULL        // Additional application data
    );

    if (hwnd == NULL)
    {
        return 0;
    }

    ShowWindow(hwnd, nCmdShow);

    // Run the message loop.

    MSG msg = { };
    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    return 0;
}

LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    switch (uMsg)
    {
    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;

    case WM_PAINT:
    {
        PAINTSTRUCT ps;

        HDC hdc = BeginPaint(hwnd, &ps);
        SelectObject(bmpdc, hBmp_red);
        StretchBlt(memdc, 0, 0, 100, 100, bmpdc, 0, 0, 10, 10, SRCCOPY);
        membmp = CreateCompatibleBitmap(hdc, 100, 100);
        SelectObject(memdc, membmp);
        BitBlt(hdc, 0, 0, 100, 100, memdc, 100, 100, SRCCOPY);

        EndPaint(hwnd, &ps);
    }
    return 0;

    }
    return DefWindowProc(hwnd, uMsg, wParam, lParam);
}