[MiNT] XaAES: detect pixel-format-problem

["Helmut Karlowski" <hk10@gmx.de>]

What I found about the pixel-detection:

detect_pixel_format uses vs_color to set a certain rgb-value. According
to Reschke's Atari-Bible this works only if
CLUT(color-lookup-table)-support is present. But it is not, neither in
1.16.3 nor 1.17 (aranym, 16 bit). So it is understandable why the test
fails. I don't understand why it works in 1.16.3, but who wants to know
everything?

If I use e.g.:

    {
    RECT r = {0,0,v->screen.w,v->screen.h};
    (*v->api->f_color)(v, 6 );
    (*v->api->gbar)( v, 0, &r );
    }

to set and draw a yellow color, the test succeeds and reports
the correct motorola-format.

This is only reliable if the palette is set accordingly. I think the first  
16
colors are always defined, and no one changes the palette at this stage
in the bootup-process, so it may be a working solution.

Maybe the GEM-Gurus can tell more about this.

The bar may be smaller in a final version ..


-Helmut