四赢不会在lwjgl中心绕中心旋转

Question

我的代码是：

GL11.glPushMatrix();

// rotate around center
GL11.glTranslatef(-200/2, -200/2, 0);      
GL11.glRotatef(30, 0.0f, 0.0f, 1);
GL11.glTranslatef(200/2, 200/2, 0);
// draw quad
GL11.glBegin(GL11.GL_QUADS);
GL11.glTexCoord2f(0f,0.5f);
GL11.glVertex3f(50,50,1);
GL11.glTexCoord2f(0.5f,0.5f);
GL11.glVertex3f(50+200,50,1);
GL11.glTexCoord2f(0.5f,0f);
GL11.glVertex3f(50+200,50+200,1);
GL11.glTexCoord2f(0f,0f);
GL11.glVertex3f(50,50+200,1);
GL11.glEnd();

GL11.glPopMatrix();

它并没有围绕中心旋转，我这样做是否正确？如果不是我怎么样？