在OpenGL中圍繞自身旋轉對象

Question

我在旋轉周圍的房間時遇到問題。它的中心位於（5,5,0），所以我想如果我用glTranslatef（5,5,5）然後glRotatef（rotateroom，0,0,1）翻譯房間和房間中的物體，然後繪製物品並使用glTranslate（-5，-5,0）它會旋轉房間和其中的所有東西在5,5,0左右，但它似乎仍然在旋轉（0,0,0），我不確定是什麼我做錯了。我在這裏先向您的幫助表示感謝。

void drawside(){ 
    int i,j; 
    /*for (j = 0; j <= 8; j++) { 
     glBegin(GL_LINE_STRIP); 
     for (i = 0; i <= 30; i++) 
      glEvalCoord2f((GLfloat)i/30.0, (GLfloat)j/8.0); 
     glEnd(); 
     glBegin(GL_LINE_STRIP); 
     for (i = 0; i <= 30; i++) 
      glEvalCoord2f((GLfloat)j/8.0, (GLfloat)i/30.0); 
     glEnd(); 
    }*/ 
    glEvalMesh2(GL_FILL, 0, 20, 0, 20); 
} 
void drawRoom(){ 
    //floor 
    glBegin(GL_POLYGON); 
    glColor3f(1,1,1); 
    glNormal3f(0,0,0); 
    glVertex3f(0,0,0); 
    glNormal3f(0,10,0); 
    glVertex3f(0,10,0); 
    glNormal3f(10,10,0); 
    glVertex3f(10,10,0); 
    glNormal3f(10,0,0); 
    glVertex3f(10,0,0); 
    glEnd(
    ); 
    //wall 
    glBegin(GL_POLYGON); 
    glColor3f(0,0,1); 
    glNormal3f(0,10,0); 
    glVertex3f(0,10,0); 
    glNormal3f(0,10,10); 
    glVertex3f(0,10,10); 
    glNormal3f(10,10,10); 
    glVertex3f(10,10,10); 
    glNormal3f(10,10,0); 
    glVertex3f(10,10,0); 
    glEnd(); 
    //wall2 
    glBegin(GL_POLYGON); 
    glColor3f(0,1,0); 
    glNormal3f(10,10,0); 
    glVertex3f(10,10,0); 
    glNormal3f(10,10,0); 
    glVertex3f(10,10,10); 
    glNormal3f(10,0,10); 
    glVertex3f(10,0,10); 
    glNormal3f(10,0,0); 
    glVertex3f(10,0,0); 
    glEnd(); 
} 
void drawObjects(){ 
    glColor3f(1,0,1); 
    glTranslatef(2,2,0); 
    if(conefill == 1) 
     glShadeModel(GL_FLAT); 
    else 
     glShadeModel(GL_SMOOTH); 
    glutSolidCone(cone,5,10,2); 
    glTranslatef(5,5,0); 
    glColor3f(1,0,0); 
    if(spherefill == 1) 
     glShadeModel(GL_FLAT); 
    else 
     glShadeModel(GL_SMOOTH); 
    glutSolidSphere(sphere,20,20); 

} 

void display(){ 
    glMatrixMode(GL_MODELVIEW); 
    glLoadIdentity(); 
    gluLookAt(viewx,viewy, viewz,viewx +lx, 5, viewz + ly,0.0f, 0.0f, 1.0f); 
    //gluLookAt(viewx,viewy,viewz,headup,headright,5,0,0,1); 
    glClear(GL_COLOR_BUFFER_BIT); 
    GLfloat light_position[] = {-1.0,5.0,5.0,0.0}; 
    //GLfloat light_direction[] = {-5,-5,-5}; 
    //GLfloat amb[] = {0,0,0,1}; 
    glLightfv(GL_LIGHT0, GL_POSITION, light_position); 
    //glLightfv(GL_LIGHT0, GL_SPOT_DIRECTION,light_direction); 
    //glLightfv(GL_LIGHT0, GL_AMBIENT,amb); 
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 
    glPushMatrix(); 
    glTranslatef(5,5,0); 
    glRotatef(rotateroom,0,0,1); 
    glPushMatrix(); 
    drawRoom(); 
    glPopMatrix(); 
    glColor3f(0.0, 0.0, 1.0); 
    glPushMatrix(); 
    glTranslatef(6,3,1); 
    glPushMatrix(); 
    drawside(); 
    glPopMatrix(); 
    glPushMatrix(); 
    //glTranslatef(5,0,0); 
    glRotatef(90,1,0,0); 
    //glTranslatef(-5,0,0); 
    glTranslatef(0,.5,.5); 
    drawside(); 
    glPopMatrix(); 
    glPushMatrix(); 
    //glTranslatef(5,0,0); 
    glRotatef(180,1,0,0); 
    //glTranslatef(-5,0,0); 
    glTranslatef(0,1,0); 
    drawside(); 
    glPopMatrix(); 
    glPushMatrix(); 
    glRotatef(90,0,0,1); 
    glTranslatef(-.5,.5,0); 
    drawside(); 
    glPopMatrix(); 
    glPushMatrix(); 
    glRotatef(270,0,0,1); 
    glTranslatef(.5,.5,0); 
    drawside(); 
    glPopMatrix(); 
    glPopMatrix(); 
    drawObjects(); 
    glTranslatef(-5,-5,0); 
    glPopMatrix(); 
    glutSwapBuffers(); 
    glFlush(); 
} 

Answer 1

你只需要翻轉istruction的順序：

glRotatef(rotateroom,0,0,1); 
glTranslatef(5,5,0); 

每當你trasform點必須反轉要應用改造中的順序。這取決於變換矩陣的乘法方式。