如果想要很好的理解这个坐标系。写一段代码，测试下面的函数就可以了：

void DrawCube(float xPos, float yPos, float zPos)

{

glPushMatrix();

glTranslatef(xPos, yPos, zPos);

glBegin(GL_POLYGON);

glVertex3f(0.0f, 0.0f, 0.0f); // top face

glVertex3f(0.0f, 0.0f, -1.0f);

glVertex3f(-1.0f, 0.0f, -1.0f);

glVertex3f(-1.0f, 0.0f, 0.0f);

glVertex3f(0.0f, 0.0f, 0.0f); // front face

glVertex3f(-1.0f, 0.0f, 0.0f);

glVertex3f(-1.0f, -1.0f, 0.0f);

glVertex3f(0.0f, -1.0f, 0.0f);

glVertex3f(0.0f, 0.0f, 0.0f); // right face

glVertex3f(0.0f, -1.0f, 0.0f);

glVertex3f(0.0f, -1.0f, -1.0f);

glVertex3f(0.0f, 0.0f, -1.0f);

glVertex3f(-1.0f, 0.0f, 0.0f); // left face

glVertex3f(-1.0f, 0.0f, -1.0f);

glVertex3f(-1.0f, -1.0f, -1.0f);

glVertex3f(-1.0f, -1.0f, 0.0f);

glVertex3f(0.0f, 0.0f, 0.0f); // bottom face

glVertex3f(0.0f, -1.0f, -1.0f);

glVertex3f(-1.0f, -1.0f, -1.0f);

glVertex3f(-1.0f, -1.0f, 0.0f);

glVertex3f(0.0f, 0.0f, 0.0f); // back face

glVertex3f(-1.0f, 0.0f, -1.0f);

glVertex3f(-1.0f, -1.0f, -1.0f);

glVertex3f(0.0f, -1.0f, -1.0f);

glEnd();

glPopMatrix();

}