OpenGL只有2个四边形显示

Question

我想在openGL中创建一个房间，然而我有以下四边形但是wall2和wall4不显示。我猜这是与视角有关，如果我走出房间，我可以看到他们已经被渲染。

glColor3f(0.1f, 0.9f, 0.9f); 
//Wall1 
glBegin(GL_QUADS); 
glNormal3f(0,0,1); 
glVertex3f(-10,0,-10); 
glVertex3f(10,0,-10); 
glVertex3f(10,5,-10); 
glVertex3f(-10,5,-10); 
glEnd(); 

//Wall2 
glColor3f(1.0f, 1.0f, 1.0f); 
glBegin(GL_QUADS); 
glNormal3f(0,0,1); 
glVertex3f(-10,0, 10); 
glVertex3f(10,0, 10); 
glVertex3f(10,5, 10); 
glVertex3f(-10,5, 10); 
glEnd(); 

//Wall3 
glColor3f(0.4f, 0.9f, 0.1f); 
glBegin(GL_QUADS); 
glNormal3f(-1,0, 0); 
glVertex3f(10,0,-10); 
glVertex3f(10,0,10); 
glVertex3f(10,5,10); 
glVertex3f(10,5,-10); 
glEnd(); 

//Wall4 
glColor3f(0.1f, 0.2f, 0.2f); 
glBegin(GL_QUADS); 
glNormal3f(1, 0, 0); 
glVertex3f(-10,0,-10); 
glVertex3f(-10,0,10); 
glVertex3f(-10,5,10); 
glVertex3f(-10,5,-10); 
glEnd(); 

Answer 1

尝试禁用脸部剔除！ :)