用vc++6.0编写一个单位立方体的正平行投影程序

好的，下面是一个简单的VC++6.0程序，可以实现单位立方体的正平行投影：

#include <windows.h>

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    WNDCLASS wc = {0};
    wc.lpfnWndProc = WndProc;
    wc.hInstance = hInstance;
    wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
    wc.lpszClassName = "Projection";

    if (!RegisterClass(&wc))
        return 1;

    HWND hWnd = CreateWindow("Projection", "Unit Cube Projection", WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 600, 600, NULL, NULL, hInstance, NULL);

    if (!hWnd)
        return 2;

    ShowWindow(hWnd, nCmdShow);
    UpdateWindow(hWnd);

    MSG msg = {0};

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

    return (int)msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)
    {
        case WM_PAINT:
        {
            PAINTSTRUCT ps;
            HDC hdc = BeginPaint(hWnd, &ps);

            // 设置投影参数
            int x0 = 100, y0 = 100;  // 投影平面的左上角坐标
            int w = 400, h = 400;    // 投影平面的宽度和高度

            // 绘制投影平面
            Rectangle(hdc, x0, y0, x0 + w, y0 + h);

            // 绘制单位立方体的六个面
            // front face
            MoveToEx(hdc, x0 + 100, y0 + 100, NULL);
            LineTo(hdc, x0 + 200, y0 + 100);
            LineTo(hdc, x0 + 200, y0 + 200);
            LineTo(hdc, x0 + 100, y0 + 200);
            LineTo(hdc, x0 + 100, y0 + 100);

            // back face
            MoveToEx(hdc, x0 + 150, y0 + 150, NULL);
            LineTo(hdc, x0 + 250, y0 + 150);
            LineTo(hdc, x0 + 250, y0 + 250);
            LineTo(hdc, x0 + 150, y0 + 250);
            LineTo(hdc, x0 + 150, y0 + 150);

            // top face
            MoveToEx(hdc, x0 + 100, y0 + 100, NULL);
            LineTo(hdc, x0 + 150, y0 + 150);
            MoveToEx(hdc, x0 + 200, y0 + 100, NULL);
            LineTo(hdc, x0 + 250, y0 + 150);
            MoveToEx(hdc, x0 + 200, y0 + 200, NULL);
            LineTo(hdc, x0 + 250, y0 + 250);
            MoveToEx(hdc, x0 + 100, y0 + 200, NULL);
            LineTo(hdc, x0 + 150, y0 + 250);

            EndPaint(hWnd, &ps);
        }
        break;

        case WM_DESTROY:
            PostQuitMessage(0);
            break;

        default:
            return DefWindowProc(hWnd, message, wParam, lParam);
    }

    return 0;
}

该程序使用Win32 API绘制单位立方体和投影平面。在窗口客户区绘制投影平面，并在投影平面上用线条绘制立方体的前、后、上、下、左、右六个面。您可以将代码复制到VC++6.0的工程中编译运行，看看效果。