c语言生成怎么生成两个图形窗口

在 C 语言中，可以使用不同的图形库来生成窗口。其中比较常用的是 Windows API 和 OpenGL。

使用 Windows API，可以使用 CreateWindow 函数创建一个新的窗口，例如：

#include <windows.h>

LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    // Register the window class.
    const char CLASS_NAME[]  = "My 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
        "Window 1",                     // Window title
        WS_OVERLAPPEDWINDOW,            // 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
        );

    // Show the window
    ShowWindow(hwnd, nCmdShow);

    // Create a second window.
    HWND hwnd2 = CreateWindowEx(
        0,                              // Optional window styles.
        CLASS_NAME,                     // Window class
        "Window 2",                     // Window title
        WS_OVERLAPPEDWINDOW,            // 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
        );

    // Show the second window
    ShowWindow(hwnd2, 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;

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

这个程序会创建两个窗口，分别显示 "Window 1" 和 "Window 2"。

使用 OpenGL，可以使用 glut 库，例如：

#include <GL/glut.h>

void display1()
{
    // Set the clear color to black
    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);

    // Clear the screen
    glClear(GL_COLOR_BUFFER_BIT);

    // Draw a red triangle
    glBegin(GL_TRIANGLES);
    glColor3f(1.0f, 0.0f, 0.0f);
    glVertex2f(-0.5f, -0.5f);
    glVertex2f( 0.5f, -0.5f);
    glVertex2f( 0.0f,  0.5f);
    glEnd();

    // Swap the buffers
    glutSwapBuffers();
}

void display2()
{
    // Set the clear color to blue
    glClearColor(0.0f, 0.0f, 1.0f, 1.0f);

    // Clear the screen
    glClear(GL_COLOR_BUFFER_BIT);

    // Draw a green rectangle
    glBegin(GL_QUADS);
    glColor3f(0.0f, 1.0f, 0.0f);
    glVertex2f(-0.5f, -0.5f);
    glVertex2f( 0.5f, -0.5f);
    glVertex2f( 0.5f,  0.5f);
    glVertex2f(-0.5f,  0.5f);
    glEnd();

    // Swap the buffers
    glutSwapBuffers();
}

int main(int argc, char** argv)
{
    glutInit(&argc, argv);

    // Create the first window
    glutInitWindowSize(400, 300);
    glutInitWindowPosition(100, 100);
    glutCreateWindow("Window 1");

    // Set the display function for the first window
    glutDisplayFunc(display1);

    // Create the second window
    glutInitWindowSize(400, 300);
    glutInitWindowPosition(500, 100);
    glutCreateWindow("Window 2");

    // Set the display function for the second window
    glutDisplayFunc(display2);

    // Start the main loop
    glutMainLoop();

    return 0;
}

这个程序会创建两个窗口，分别显示一个红色的三角形和一个绿色的矩形。