Smooth tile scrolling in Direct3D

Several people have asked me to tell them how to do smooth scrolling in Direct3D.

The problem is that you cannot use the per-pixel DOS algo because this requires locking and unlocking textures which is a big no no in a render loop.

So here is the solution with code for Direct3D 9.0.

Updated versions.

Last one had several bugs

Make sure that you shut off the ZBuffer as on some cards this will prevent anything from being displayed.


g_pDevice->SetRenderState(D3DRS_ZENABLE,false);