In windows (gdi, gdi+, etc.) is there a way to make a raw a8r8g8b8 bitmap and display it on the screen from this raw data? (C++)

Yes, take a look at the GDI+ Bitmap object''s Lock function. It works basically the same way as a DirectDraw surface. You lock the surface to gain access to the data, treat it as an int array and set pixels, then unlock it. Take a look at LockBits and the Bitmap constructor. You can also use other image formats than 32-bit ARGB.