如何在其他部件旋转时阻止对象旋转

我刚刚画了一个带有 3 个关节的 3 自由度机器人，这些机器人是旋转的，我画了一个 shere 用作障碍物，它应该是恒定的，没有任何移动，但随着机器人的抓手开始移动，我的障碍物也会移动，这不应该，第二个问题是：我想转身我的机器人，我通过箭头键做了这个没有错误，但它确实有效。

#include <GL/glut.h>
#include <stdio.h>
#include <stdlib.h>
#define VIEW_TURN_RATE  10
#define GLUT
#define GLUT_KEY
#define GLUT_SPEC
float t1=30;
float t2=45;
float t3=45;
float t4=0;
float t5=0;
float l=1.5;
float h=0.2*l;
double m=0.2;
double n=0.2;
double p=0.2;
float eyex,eyey=0;
float eyez=6;
float lx,ly,lz=0;
int turn = 0, turn1 = 0;
void TurnRight(void)
{
    turn = (turn - VIEW_TURN_RATE) % 360;
}
void TurnLeft(void)
{
    turn = (turn + VIEW_TURN_RATE) % 360;
}
void TurnForwards(void)
{
    turn1 = (turn1 - VIEW_TURN_RATE) % 360;
}
void TurnBackwards(void)
{
    turn1 = (turn1 + VIEW_TURN_RATE) % 360;
}
void myidlefunc()
{
    if(t1<100)
        t1+=2;
    else
    {   
        if(t2<150)
            t2+=2;
        else
        {
            if(t3<150)
                t3+=2;
            else
            {
                if(t4<150)
                    t4+=2;
                else
                {
                    if(t5<120)
                        t5+=2;
                    else
                    {
                        glutIdleFunc(0);
                    }
                }
            }
        }
    }
    glutPostRedisplay();
}
#ifdef GLUT
#ifdef GLUT_SPEC
void
    special(int key, int x, int y)
{
    int i = 0;
    printf("this is special keyboard: %d n",key);
    switch (key) {
        /* start of view position functions */
    case 'r':{
        TurnRight();
        i++;
             }
             break;
    case GLUT_KEY_LEFT:{
        TurnLeft();
        i++;
                       }
                       break;
    case GLUT_KEY_DOWN:{
        TurnForwards();
        i++;
                       }
                       break;
    case GLUT_KEY_UP:{
        TurnBackwards();
        i++;
                     }
                     break;
                     /* end of view postions functions */
    }
    if (i)
        glutPostRedisplay();
}
#endif
#ifdef GLUT_KEY
void keyboard(unsigned char c,int x,int y)
{
    switch(c)
    {
    case 27:
        exit(0);
        break;
    case 's':
        if (t1 < 50) {
            t1++;}
        break;
    case 'S':
        //if (t1 < 80) {
        t1--;
        //}
        break;
    case 'q':
        glutIdleFunc(myidlefunc);
        break;
    case 'f':
        if (t2 < 160) {
            t2++;}
        break;
    case 'F':
        t2--;
        break;
    case 'g':
        t3++;
        break;
    case 'h':
        t4++;
        break;
    case 'k':
        t5++;
        break;
    }
    glutPostRedisplay();
}
#endif
#endif
void drawFloor(void)
{
    glPushMatrix ();
    glBegin(GL_QUADS);
    glColor3f(0.0,0.8,0.8);
    glVertex3f(-20.0, 0.0, 100.0);
    glVertex3f(20.0, 0.0, 100.0);
    glVertex3f(20.0, 0.0, -100.0);
    glVertex3f(-20.0, 0.0, -100.0);
    glEnd();
    glPopMatrix ();
    glEnable(GL_LIGHTING);
}
void Base(float l)
{
    glPushMatrix();
    //glColor3f(0.4,0.6,0.5);
    glScaled(1.0*l,0.2*l,1.0*l);
    glutSolidCube(1);
    glPopMatrix();
}
void obst(float radius, int slices, int stacks)
{
    glTranslated (0,-0.5,0.0);
    glPushMatrix ();
    glutSolidSphere (radius,slices,stacks);
    glPopMatrix ();
}
void arm(float l,float r,int slices,int stacks,float rotat)
{
    float d;
    d=0.2*l;
    glTranslated (0,l/2+d/2,0);
    glPushMatrix ();
    glScaled (d/l,1,d/l);
    glutSolidCube (l);
    glPopMatrix ();
    glTranslated (0,l/2,0);
    glRotated (rotat,0,0,1);
    glPushMatrix ();
    glutSolidSphere (r,slices,stacks);
    glPopMatrix ();
}
void Base2(float l,float r,int slices,int stacks,float rotat)
{
    float d;
    d=0.2*l;
    glTranslated (d/2,d/2,d/2);
    glPushMatrix ();
    glScaled (d,d/2,d);
    glutSolidCube (2);
    glPopMatrix ();
}
void hand(float d,float x)
{
    glColor3f(0.0,0.4,0.3);
    glRotated(t5,0,1,0);
    glPushMatrix ();
    glTranslated(0,-d/2+x/2,0);
    glScaled(1,x/d,1);
    glutSolidCube (d);
    glPopMatrix();
    glPushMatrix ();
    glTranslated(-d/2+x/2,x/2,0);
    glScaled (x/(d-x),1,d/(d-x));
    glutSolidCube(d-x);
    glPopMatrix ();
    glPushMatrix ();
    glTranslated (d/2-x/2,x/2,0);
    glScaled (x/(d-x),1,d/(d-x));
    glutSolidCube(d-x);
    glPopMatrix ();
}
void display()
{
    float l,T,r,x,d;
    double radius,height;
    int slices, stacks;
    l=1.5;
    T=30;
    d=0.2*l;
    x=0.2*d;
    r=d/2;
    radius=1.0;
    height=3;
    slices=1000;
    stacks=202;
    glClearColor(1.0,1.0,1.0,1.0);
    glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
    glPushMatrix ();
    //lightning start here
    glEnable(GL_LIGHT0);
    GLfloat light0_pos []={lx,ly+1,lz+1,1};
    GLfloat light0_diffuse []={1,0,0,0};
    glLightfv(GL_LIGHT0,GL_DIFFUSE,light0_diffuse);
    GLfloat light0_Ambient []={0,1,1,0};
    glLightfv(GL_LIGHT0,GL_DIFFUSE,light0_Ambient);
    gluLookAt(0.2,0.8,0.0,5.0,3.0,5.0,0.0,0.1,0.0);
    glLightfv(GL_LIGHT0,GL_POSITION,light0_pos);
    glScaled(0.2,0.2,0.2);
    glRotated(90,0.0,1.0,0.0);

    /* Draw "bottom" of floor in blue. */
    glColor3f(0.0, 0.8, 0.8);
    drawFloor();
    //base
    glColor3f(0.0,0.0,0.0);
    Base(2);
    //base2
    glColor3f(1.0,0.0,0.0);
    Base2(l,r,60,60,t1);
    //arm1  
    glColor3f(1.0,0.0,0.8);
    arm(l,r,60,60,t1);
    glColor3f(0.0,1.0,0.0);
    arm(l,r,60,60,t2);
    glColor3f(1.0,0.8,0.5);
    arm(l,r,60,60,t3);

    //hand   
    glTranslated (0,d/2+r,0);
    hand(d,x);
    //obst
    glTranslated (-1,3,0);
    glColor3f(0.0,0.0,1.0);
    obst(radius,slices,stacks);
    //glRotated(0.0,0.0,1.0,0.0);
    glPopMatrix ();
    glFlush();
    glutSwapBuffers();  
}
void reshape(int width,int height)
{
    float aspect=(float)width/(float)height;
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glViewport(0,0,width,height);
    //glOrtho(-aspect,aspect,-1,+1,-1,+1);
    gluPerspective(60.0,0.0,0.0,8);
    glMatrixMode (GL_MODELVIEW);
    glLoadIdentity();
    //glTranslatef(0.0, 0.0, 0.0);  /* viewing transform  */
}
int main(int argc,char** argv)
{ 
    glutInit(&argc,argv);
    glutInitDisplayMode(GLUT_RGBA|GLUT_DOUBLE);
    glutInitWindowPosition(0,0);
    glutInitWindowSize(500,500);
    static int window=glutCreateWindow("OPenGL!");
    glutDisplayFunc(display);
    glutReshapeFunc(reshape);
    glutKeyboardFunc(keyboard);
#ifdef GLUT_SPEC
    glutSpecialFunc(special);
#endif
    glShadeModel(GL_FLAT);
    glEnable(GL_LIGHTING);
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_COLOR_MATERIAL);
    glutMainLoop();
    exit(0);
}