#include
     
      #include 
      
       //旧版本 固定管线#include
       
        #include 
        
         using namespace std;const GLdouble twoPi = 6.283185;struct screenPt {    GLint x, y;};typedef enum{ limacon =1, cardioid, threeLeaf, fourLeaf, spiral} curveName;GLsizei winWidth = 600, winHeight = 500;void init(){    //窗口背景为白色    glClearColor(1, 1, 1, 1);    glMatrixMode(GL_PROJECTION);    gluOrtho2D(0.0, 200.0, 0.0, 150.0);}void lineSegment(screenPt pt1, screenPt pt2){    glBegin(GL_LINES);    glVertex2i(pt1.x, pt1.y);    glVertex2i(pt2.x, pt2.y);    glEnd();}void drawCurve(GLint curveNum){    const GLdouble twoPi = 6.283185;    const GLint a = 175, b = 60;    GLfloat r, theta, dtheta = 1.0 / float(a);    GLint x0 = 200, y0 = 250;    screenPt curvePt[2];    glColor3f(0.0, 0.0, 0.0);    curvePt[0].x = x0;    curvePt[0].y = y0;    switch (curveNum) {    case limacon:        curvePt[0].x += a + b;        break;    case cardioid:        curvePt[0].x += a + a;        break;    case threeLeaf:        curvePt[0].x += a;        break;    case fourLeaf:        curvePt[0].x += a;        break;    case spiral:        break;    default:        break;    }    theta = dtheta;    while (theta < twoPi) {        switch (curveNum) {        case limacon:            r = a * cos(theta) + b;            break;        case cardioid:            r = a * (1 + cos(theta));            break;        case threeLeaf:            r = a * cos(theta * 3);            break;        case fourLeaf:            r = a * cos(theta * 2);            break;        case spiral:            r = (a / 4.0) * theta;            break;        default:            break;        }        curvePt[1].x = x0 + r * cos(theta);        curvePt[1].y = y0 + r * sin(theta);        lineSegment(curvePt[0], curvePt[1]);                curvePt[0].x = curvePt[1].x;        curvePt[0].y = curvePt[1].y;        theta += dtheta;    }}void displayFcn(){        GLint curveNum;    glClear(GL_COLOR_BUFFER_BIT);    glColor3f(0.0, 0.0, 1.0);    cout << "选择下列任意图形进行绘制\n";    cout << "1-limacon, 2-cardioid, 3-threeLeaf, 4-fourLeaf, 5-spiral\n";        if (curveNum == 1 || curveNum == 2 || curveNum == 3 || curveNum == 4 || curveNum == 5) {        drawCurve(curveNum);    }    else {        exit(0);    }        glFlush();    }void winReshapeFcn(GLint newWidth, GLint newHeight){    glMatrixMode(GL_PROJECTION);    glLoadIdentity();    gluOrtho2D(0.0, GLdouble(newWidth), 0.0, GLdouble(newHeight));    glClear(GL_COLOR_BUFFER_BIT);    winWidth = newWidth;    winHeight = newHeight;}int main(int argc, char* argv[]){
        glutInit(&argc, argv);    glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);    glutInitWindowPosition(100, 100);    glutInitWindowSize(winWidth, winHeight);    glutCreateWindow("Curves");    init();       glutDisplayFunc(displayFcn);    glutReshapeFunc(winReshapeFcn);    glutMainLoop();    system("pause");    return 0;}