[maemo-developers] [maemo-developers] Nokia SDL color format for pixels

[From: Michael Stepanov]

Found the problem. It's Big/Little Endian issue. It seems that SDL pixel
format doesn't take into account the byte order for *[RGBA]shift:

SDL_PixelFormat * PF = screen->format;

How can I modify the statement:

*PixelSrc = (ColorToReplace.R() << PF->Rshift) | (ColorToReplace.G() <<
PF->Gshift) | (ColorToReplace.B() << PF->Bshift);

To use correct shift for little endian?

On Fri, Aug 29, 2008 at 10:44 AM, Michael Stepanov <michael at stepanoff.org>wrote:

> Thanks a lot, guys, for your help. Finally I managed to get correct RGB
> from the 16bit pixel using SDL_GetRGB. First I get a pixel and then retrieve
> RGB from it:
>
>    Uint8 red, green, blue;
>    Uint32 pixel;
>
>    for(int y = 0; y < 480; y++)
>    {
>        for(int x = 0; x < 640; x++)
>        {
>            pixel = getpixel(surface, x, y);
>            SDL_GetRGB((Uint32)pixel, surface->format, &red, &green, &blue);
>        }
>    }
>
>    But now I have another problem. There is a transformation of color:
>
>    PixelSrc = (ColorToReplace.R() << PF->Rshift) | (ColorToReplace.G() <<
> PF->Gshift) | (ColorToReplace.B() << PF->Bshift);
>
> Where ColorToReplace is (255,102,155)
>
> But after that transformation it becomes (255, 252, 7). Could somebody tell
> me where is a mistake?
>
> TIA
>
> P. S. Sorry for not clever questions. I don't have a big C++ and SDL
> practice.
>
> --
> Cheers,
> Michael
>



-- 
Cheers,
Michael
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