I'm trying to draw a triangle inside a Direct3D9 window that belongs to another program. Athough everything seems to be ok, and all of the functions return without errors, the triangle doesn't get drawn. I'm puzzled: what could be the reason it's not getting drawn? P.S. I do the drawing by intercepting Present, and the hook is called, as is evident inside the debugger, the triangle should not be clipped since it is inside the window boundaries. Everything works fine in my test application.

I've just checked MH's hooking example - it doesn't work either. Will check the PIX tool now :)

Currently I'm using this code (It's not really RHW anymore, since I'm transforming the vertices, but it's the same thing, AFAIK. I'm using an orthographic projection matrix for camera and identity matrices for world and view)

pDevice->GetTransform(D3DTS_VIEW,&mOldView);
pDevice->GetTransform(D3DTS_PROJECTION,&mOldProject);
pDevice->GetTransform(D3DTS_WORLD,&mOldWorld);

pDevice->SetTransform(D3DTS_VIEW,&mView);
pDevice->SetTransform(D3DTS_PROJECTION,&mProject);
pDevice->SetTransform(D3DTS_WORLD,&mWorld);

pDevice->SetRenderState(D3DRS_ZENABLE,D3DZB_FALSE);
if (pDevice->BeginScene()==0)
{
pDevice->SetStreamSource( 0, pVB, 0, sizeof(CUSTOMVERTEX) );
pDevice->SetFVF( D3DFVF_CUSTOMVERTEX );
pDevice->DrawPrimitive( D3DPT_TRIANGLELIST, 0, 1 );
}
pDevice->EndScene();
pDevice->SetRenderState(D3DRS_ZENABLE,D3DZB_TRUE);

pDevice->SetTransform(D3DTS_VIEW,&mOldView);
pDevice->SetTransform(D3DTS_PROJECTION,&mOldProject);
pDevice->SetTransform(D3DTS_WORLD,&mOldWorld);

Yeah, I noticed the problem with culling after posting. Culling is now disabled, the triangle is still not getting drawn.