在openGL中用鼠标绘制

#include <GL/glut.h>

// 记录鼠标点击的位置
int x1 = 0, y1 = 0;
int x2 = 0, y2 = 0;

// 鼠标点击事件处理器
void mouse(int button, int state, int x, int y) {
    if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN) {
        x1 = x;
        y1 = y;
    }
}

// 鼠标移动事件处理器
void motion(int x, int y) {
    x2 = x;
    y2 = y;
    glClear(GL_COLOR_BUFFER_BIT);
    glBegin(GL_LINE_STRIP);
    glVertex2i(x1, y1);
    glVertex2i(x2, y2);
    glEnd();
    glFlush();
}

// 初始化OpenGL窗口和鼠标事件处理器
int main(int argc, char** argv) {
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
    glutInitWindowSize(800, 600);
    glutInitWindowPosition(100, 100);
    glutCreateWindow("OpenGL绘图");
    glClearColor(1.0, 1.0, 1.0, 0.0);
    glMatrixMode(GL_PROJECTION);
    gluOrtho2D(0, 800, 0, 600);
    glutMouseFunc(mouse);
    glutMotionFunc(motion);
    glutMainLoop();
    return 0;
}