Trouble translating a C expression to Ada

["file13" <file13@qlippoth.zzn.com>]

Howdy all,

I've been going through "Programming Linux Games"
( http://www.nostarch.com/plg.htm )
and translating the SDL examples to Ada using AdaSDL
( https://sourceforge.net/projects/adasdl/ or
http://www.adapower.net/%7Eavargas/ )
and I've run into a snag.  How would one translate this expression into Ada:

raw_pixels[offset] = pixel_color;

where raw_pixels is a pointer to a SDL Uint16 type (i.e. Uint16
*raw_pixels;)
offset is an integer, and pixel_color is a SDL Uint16 type (not a pointer).

The original C is here:
http://www.qlippoth.com/direct-pixel-drawing-sdl.c

and what I've got so far on the Ada version is here:
http://www.qlippoth.com/direct_pixel_drawing_sdl.adb

I'm using Gnat-3.13p on Mandrake 8.1

Would SDL.Types.Increment be the correct way to do this and if so
would we require more Unchecked_Conversions?

one of it's prototypes is:
function Increment (
      Pointer : Uint16_Ptrs.Object_Pointer;
      Amount : Natural) return Uint16_Ptrs.Object_Pointer;
pragma Inline (Increment);

The gnathtml docs are here:
http://www.adapower.net/~avargas/SDL/AdaSDLhtml/index.htm

Also, if you find any other problems please let me know.  :)

Thank you!

--
file13
http://www.qlippoth.com/