OpenGl:模板缓冲区问题(“墙+窗口")?

我想使用模板缓冲区创建一面带有窗口的墙. 我的代码如下:

I want to create a wall with a window inside, using stencil buffer. My code looks like this:

glEnable(GL_STENCIL_TEST);
glClearStencil(0);
glClear(GL_STENCIL_BUFFER_BIT);
glStencilMask(1);
glStencilFunc(GL_ALWAYS, 1, 1);

glStencilOp(GL_REPLACE, GL_REPLACE, GL_REPLACE);
glDisable(GL_DEPTH_TEST);   
glColor3f(1,1,1);

//Window
glBegin(GL_POLYGON);
glVertex3d(-5,0,-20);
glVertex3d(-5,0,40);
glVertex3d(-20,0,40);
glVertex3d(-20,0,-20);
glEnd();

glEnable(GL_DEPTH_TEST);
glStencilFunc(GL_NOTEQUAL, 1, 1);
glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);

glEnable(GL_CLIP_PLANE0);                       
glClipPlane(GL_CLIP_PLANE0, eqr);   
glBindTexture(GL_TEXTURE_2D,texture[1]);
glBegin(GL_POLYGON);
glNormal3f(0.0f,-1.0,0.0f);

//Wall
glTexCoord2f(0.0f, 0.0f);glVertex3d(20,0,-20);
glTexCoord2f(1.0f, 0.0f);glVertex3d(20,0,40);
glTexCoord2f(1.0f, 0.0f);glVertex3d(-20,0,40);
glTexCoord2f(1.0f, 0.0f);glVertex3d(-20,0,-20);

glEnd();
glDisable(GL_STENCIL_TEST);

但是那行不通，我得到了整个填充墙，没有窗户在里面，有什么建议吗?

But that doesn't work out, I got the whole fill wall without the window in it, any suggestions??