《高效学习OpenGL》 之 创建机器人手臂源码讲解

#include <GL/glut.h>#include <stdlib.h>static int shoulder = 0, elbow = 0;void init(void) {   glClearColor (0.0, 0.0, 0.0, 0.0);   glShadeModel (GL_FLAT);}void display(void){   glClear (GL_COLOR_BUFFER_BIT);   glPushMatrix();   glTranslatef (-1.0, 0.0, 0.0);//转移局部坐标系中心-1   glRotatef ((GLfloat) shoulder, 0.0, 0.0, 1.0);//绕局部坐标系原点旋转   glTranslatef (1.0, 0.0, 0.0);//把局部坐标系转回立方体中心   glPushMatrix();   glScalef (2.0, 0.4, 1.0);   glutWireCube (1.0);   glPopMatrix();   glTranslatef (1.0, 0.0, 0.0);//转移局部坐标系到第一个立方体的右侧   glRotatef ((GLfloat) elbow, 0.0, 0.0, 1.0);//绕局部坐标系旋转   glTranslatef (1.0, 0.0, 0.0);//转移到第二个立方体中心   glPushMatrix();   glScalef (2.0, 0.4, 1.0);   glutWireCube (1.0);   glPopMatrix();   glPopMatrix();   glutSwapBuffers();}void reshape (int w, int h){   glViewport (0, 0, (GLsizei) w, (GLsizei) h);    glMatrixMode (GL_PROJECTION);   glLoadIdentity ();   gluPerspective(65.0, (GLfloat) w/(GLfloat) h, 1.0, 20.0);   glMatrixMode(GL_MODELVIEW);   glLoadIdentity();   glTranslatef (0.0, 0.0, -5.0);}void keyboard (unsigned char key, int x, int y){   switch (key) {      case 's':         shoulder = (shoulder + 5) % 360;         glutPostRedisplay();         break;      case 'S':         shoulder = (shoulder - 5) % 360;         glutPostRedisplay();         break;      case 'e':         elbow = (elbow + 5) % 360;         glutPostRedisplay();         break;      case 'E':         elbow = (elbow - 5) % 360;         glutPostRedisplay();         break;      case 27:         exit(0);         break;      default:         break;   }}int main(int argc, char** argv){   glutInit(&argc, argv);   glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB);   glutInitWindowSize (500, 500);    glutInitWindowPosition (100, 100);   glutCreateWindow (argv[0]);   init ();   glutDisplayFunc(display);    glutReshapeFunc(reshape);   glutKeyboardFunc(keyboard);   glutMainLoop();   return 0;}