DgVoodoo creator discusses Swat 3

I would be happy with 24 bit colours

Going to read your post now.

Just reading the direct draw reference page for "DirectDrawCreate".

One of the return values is "DDERR_GENERIC". Sound familiar? 

The dreaded start up/movie crash.

Update:  I also see a reference to SetPixelFormat on these pages.  Loading up Ghidra to see if Swat 3 uses this.  Nope

Right now everything I am doing is stabbing in the dark out of ignorance.  The more logical approach would be to look for an old book about DirectDraw and start reading.

I think a lot of the window creation calls also involve USER32.dll such as:
CreateWindowExA
GetWindowRect
SetRec
SetWindowPos

Update 2:   Got 2 books.  "DirectDraw programming" by Bret Timmins and "Windows Graphics Programming: Win32 and DirectDraw" by Feng Yuan.
 

Wink wink.

I did a bit of quick reading last night of the first book.   Depending how they did things it probably is more difficult than a simple hack.

One command that may be of use to us is SetDisplayMode.   You can take an existing DirectDraw object and change it by height, width, and colour depth.   RestoreDisplayMode will change it back to what it was before you made the call.