《高效学习OpenGL》 之 显示列表实例 glCallList(),glGenLists(),glNewList(),glEndList()

#include <GL/glut.h>#include <stdio.h>#include <math.h>#include <stdlib.h>#define PI_ 3.14159265358979323846GLuint theTorus;/* Draw a torus */static void torus(int numc, int numt)//显示列表只能包含OpenGL函数{   int i, j, k;   double s, t, x, y, z, twopi;   twopi = 2 * PI_;   for (i = 0; i < numc; i++) {      glBegin(GL_QUAD_STRIP);      for (j = 0; j <= numt; j++) {         for (k = 1; k >= 0; k--) {            s = (i + k) % numc + 0.5;            t = j % numt;            x = (1+.1*cos(s*twopi/numc))*cos(t*twopi/numt);            y = (1+.1*cos(s*twopi/numc))*sin(t*twopi/numt);            z = .1 * sin(s * twopi / numc);            glVertex3f(x, y, z);         }      }      glEnd();   }}/* Create display list with Torus and initialize state */static void init(void)//创建了一个绘制圆环面的显示列表{   theTorus = glGenLists (1);//glGenLists()唯一的标识一个显示列表   glNewList(theTorus, GL_COMPILE);//用于对显示列表进行定界。第一个参数是一个整形索引值，由glGenLists()指定   torus(8, 25);   glEndList();   glShadeModel(GL_FLAT);   glClearColor(0.0, 0.0, 0.0, 0.0);}/* Clear window and draw torus */void display(void){   glClear(GL_COLOR_BUFFER_BIT);   glColor3f (1.0, 1.0, 1.0);   glCallList(theTorus);//执行显示列表所存储的函数   glFlush();}/* Handle window resize */void reshape(int w, int h){   glViewport(0, 0, (GLsizei) w, (GLsizei) h);   glMatrixMode(GL_PROJECTION);   glLoadIdentity();   gluPerspective(30, (GLfloat) w/(GLfloat) h, 1.0, 100.0);   glMatrixMode(GL_MODELVIEW);   glLoadIdentity();   gluLookAt(0, 0, 10, 0, 0, 0, 0, 1, 0);}/* Rotate about x-axis when "x" typed; rotate about y-axis   when "y" typed; "i" returns torus to original view */void keyboard(unsigned char key, int x, int y){   switch (key) {   case 'x':   case 'X':      glRotatef(30.,1.0,0.0,0.0);      glutPostRedisplay();//使glutMainLoop()函数调用display()函数      break;   case 'y':   case 'Y':      glRotatef(30.,0.0,1.0,0.0);      glutPostRedisplay();      break;   case 'i':   case 'I':      glLoadIdentity();//恢复初始模型矩阵      gluLookAt(0, 0, 10, 0, 0, 0, 0, 1, 0);      glutPostRedisplay();      break;   case 27:      exit(0);      break;   }}int main(int argc, char **argv){   glutInitWindowSize(200, 200);   glutInit(&argc, argv);   glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);   glutCreateWindow(argv[0]);   init();   glutReshapeFunc(reshape);   glutKeyboardFunc(keyboard);   glutDisplayFunc(display);   glutMainLoop();   return 0;}