其实就是画球体的时候，把z值搞分化了。这个球就画凹了。
然后经过角度旋转，效果挺不错的。
看效果图

2. #include <stdlib.h>
3. #include <stdio.h>
4. #include <time.h>
5. #include <unistd.h>
6. #include <GL/glut.h>
7. #include <math.h>
9. #define xpix 400
10. #define ypix 400
12. int winid;
14. float Rtang=0.0,Ra=0.0,Rb=0.0;
15. int ArrSum;
17. float dot[140000][3];
18. float clr[140000][3];
20. void display(void)
21. {
22.    int i;
23.    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
24.    glEnableClientState(GL_VERTEX_ARRAY);
25.    glEnableClientState(GL_COLOR_ARRAY);
26.    glVertexPointer(3,GL_FLOAT,0,dot);
27.    glColorPointer(3,GL_FLOAT,0,clr);
29.    glPushMatrix();
30.      glRotatef(Rtang,1.0,0.0,0.0);
31.      glRotatef(Ra,0.0,1.0,0.0);
32.      glRotatef(Rb,1.0,0.0,0.0);
33.      glDrawArrays(GL_POINTS,0,ArrSum);
34.    glPopMatrix();
35.    glutSwapBuffers();
36. }
38. void next(void) {
39.   if (Rtang<=250.0) {
40.      usleep(1000);
41.      Rtang++;
42.      glutPostRedisplay();
43.   } else {
44.      glutIdleFunc(NULL);
45.   }
46. }
49. void init(void) {
50.     float ang,angb,len,deep,cx,cy;
51.     float add;
52.     int i=0;
53.     glClearColor(0.0,0.0,0.0,0.0);
54.     glEnable(GL_BLEND);
55.     glEnable(GL_DEPTH_TEST);
58.     for (ang=0.0;ang<3.1415/2.0;ang+=0.01) {
59.         len=100.0-cos(ang)*100.0;  //here ,100.0-cos... change to circle
60.         deep=sin(ang)*100.0;
61.           add=6.28/(2.0*3.14*len);
62.         for (angb=0.0;angb<6.28;angb+=add) {
63.             cx=cos(angb)*len;
64.             cy=sin(angb)*len;
65.             dot[i][0]=cx;   clr[i][0]=cx/100.0;
66.             dot[i][1]=cy;   clr[i][1]=cy/100.0;
67.             dot[i][2]=deep-10;  clr[i][2]=(100+deep)/200.0;
68.                i++;
69.             dot[i][0]=cx;  clr[i][0]=cx/100.0;
70.             dot[i][1]=cy;  clr[i][1]=cy/100.0;
71.             dot[i][2]=-deep+10;  clr[i][2]=(100-deep)/200.0;
72.                i++;
73.         }
74.     }
75.      ArrSum=i-1;
76.      printf("%d,\n",i);
77. }
79. void reshape(int winx,int winy) {
80.     float fa=500.0;
81.     glViewport(0,0,winx,winy);
82.     glMatrixMode(GL_PROJECTION);
83.       glLoadIdentity();
84.       gluPerspective(70.0,1.0,3.0,800.0);
85.       //glOrtho(0.0,xpix,0.0,ypix,0.0,600.0);
86.     glMatrixMode(GL_MODELVIEW);
87.       glLoadIdentity();
88.       gluLookAt(0.0,0.0,fa, 0.0,0.0,0.0, 0.0,1.0,fa);
89. }
91. void hitkey(unsigned char key,int mousex,int mousey) {
92.      static int stop=0;
93.      switch (key) {
94.        case 'q':
95.            glutDestroyWindow(winid);
96.            exit(0);
97.            break;
98.        case 'p':
99.            stop=1-stop;
100.            if (stop==1) {glutIdleFunc(NULL);} else {glutIdleFunc(next);}
101.       }
102. }
105. void mouse(int mousex,int mousey) {
106.    static int tx;
107.    static int ty;
108.    if (mousex>tx) Ra+=1;
109.    if (mousex<tx) Ra-=1;
110.    if (mousey>ty) Rb+=1;
111.    if (mousey<ty) Rb-=1;
112.    tx=mousex;
113.    ty=mousey;
114.    glutPostRedisplay();
115. }
117. int main(int argc,char *argv[])
118. {
119.      glutInit(&argc,argv);
120.      glutInitWindowSize(xpix,ypix);
121.      glutInitWindowPosition(0,0);
122.      glutInitDisplayMode(GLUT_DEPTH|GLUT_RGBA|GLUT_DOUBLE);
123.      winid=glutCreateWindow("PakTC");
124.      init();
125.      glutReshapeFunc(reshape);
126.      glutDisplayFunc(display);
127.      glutKeyboardFunc(hitkey);
128.      glutMotionFunc(mouse);
129.      glutIdleFunc(next);
130.      glutMainLoop();
131.      return 0;
132. }

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