OpenEuphoria

DirectDrawCreate/SetCooperativeMode problems

• Posted by animeshk at yahoo.com Apr 12, 2003
• 521 views

I tried using EuCOM & TBrowser to create a wrapper for
dx7vb.dll.  My first attempt to use this failed: I
used create_com_object to create the DirectX7 object,
but when I tried to use call_interface to call the
DirectX7 objects "DirectDrawCreate" method.  This
didn't work: the VB docs show that the
"DirectDrawCreate" method is supposed to return a
DirectDraw object, but call_interface only returns an
HResult.

Okay.  Next attempt!

This time, I followed what the EuCOM Direct3d demo
did.  I opened the "ddraw.dll" .dll.  I used the
following to define the DirectDrawCreate fcn:

ddrawc = define_c_func(ddrawdll, "DirectDrawCreate",
{C_POINTER, C_POINTER, C_POINTER}, C_UINT )

to define the fcn.  First param is a ptr to a GUID, in
my case null.  The second is where they will return
the pointer to the DirectDraw object.  The third is
that "unknown" param, also always set to null.

To call this, I defined a ddraw_ptr object, and I used
acquire_mem to initialize it.  I called the fcn with 

res = c_func( ddrawc, {NULL, ddraw_ptr, NULL})

Afterwards, I initialized the ddraw object by doing a
peek4u on the ddraw_ptr.  Finally, I called
ref_com_object:

ddraw = ref_com_object( DirectDraw7_clsid_ix, ddraw )

So far, so good.

Problem is when I call SetCooperativeLevel:

res = call_interface( ddraw, DirectDraw7_disp,
DirectDraw7_SetCooperativeLevel,  {
getHandle(MainWin), DDSCL_NORMAL } )

Now, I keep getting a return value of 2147500034,
which is the error code DIERR_NOAGGREGATION.  I think
this means that it thinks, in the call to
DirectDrawCreate, I didn't set the third param to null
. . . but I did.

Has anyone else seen this?  Does anyone have a
solution for this?  Thanks!
--Animesh