   How to write in another game's window?
  Using DirectDraw, how can I draw in another game''s window?  The game could be in full-screen mode or windowed mode.  Would I need to grab the games hwnd and call SetCooperativeLevel, CreateSurface, GetAttachedSurface?  I could sure use some assistance.Thanks in advance. 
  First of all, why do you want to? Things like this can be used for cheating. ;  AFIAK I''m pretty sure that you can''t do this.  Unless the applications are specifically set up to talk to each other they won''t be able to because windows puts them all in protected memory space.-me ;  This can be done.  I even worked on a project before and did it, but it was using D3D9. Check out these threads, or search the forum for ''hook'':herehereWhat you have to do is, hook your self into the game, and replace it''s directDraw interface with your own (you can create your own easily, just make it inherited from the directDraw interface).  Your ddraw interface should contain the drawing code.Please note, this is no trivial task. 