opengl通过设置纹理,映射到茶壶表面，实现两张纹理的叠合效果，现纹理和光照效果的混合，自己用代码产生一张纹理等-By setting opengl texture mapped onto the surface of the teapot to achieve the effect of two overlapping textures, mixing textures and lighting effects now, with their own code to produce a te