请教一个DirectX的纹理问题

oer33

加载后的纹理图片能不能经过裁剪后再显示?要用什么函数?
类似DirectX7.0中DirectDraw的Blt函数,通过设置RECT来裁剪

LPDIRECTDRAWSURFACE lpDDSBack;
LPDIRECTDRAWSURFACE lpDDSObj;
                Rect rt,rt2;
        rt->top = 0;
        rt->left = 0;
        rt->right = 800;
        rt->bottom = 600;
        rt2->top = 10;
        rt2->left = 10;
        rt2->right = 80;
        rt2->bottom = 80;

lpDDSBack->Blt(&rt,lpDDSObj,&rt2,DDBLT_WAIT|DDBLT_KEYSRC,NULL)