As I know the two parameters are used for initialiation of D3d Device, and their features are enable auto z-buffer control for the device. But I have the problem below. In D3d Tut 3 (Matrics), I add the code below when initial D3D deivce: d3dpp.EnableAutoDepthStencil = TRUE d3dpp.AutoDepthStencilFormat = D3DFMT_D16 it causes nothing display in the screen! Why?

P.S. It doesn''t occour error. The window can be created.
but the triangle cannot be rendered on the screen!