hello
I’ve been having a hard time recently coming to understand the
functionality of surfaces with SDL or successfully utilizing them how I
want to.
so basically from what I’ve read combined with what I know about indexed
images, it SEEMs as though the sdl_color pointer in a surface’s
format’s palette (surface->format->palette->colors) should
point to some kind of information relative to the colors defined in an
image’s palette. All the references online point to the usage of the
pointer such that colors[n] refers to a color in an image’s palette with
the index of n. Which would inherit from it’s type the Uint8 members r,
g, b.(and unused). However my tests to see what values come out for r,
g, and b when I print them out respectively for their respective color
indexes are confusing me. And either I am doing it wrong, or I am not
understanding the functionality of palettes in sdl_surfaces.
so let’s assume I create a surface from a loaded 8 bit indexed bitmap of
256 colors.
img = loadbmp(etc);
now considering that upon testing how a Uint8 variable alone prints
out…
Uint8 jimbo;
.
.
.
.
jimbo = 111;
cout<<jimbo;//prints out weird character e.g. ?
so scratch that and
cout<<(int)jimbo;//prints out 111;
that if img->format->palette->colors[0].r is printed out it
would give me the red intensity of the color with that index for that
image
cout<<(int)img->format->palette->colors[0].r;//this color
in my bitmap equals 168, 0, 255 so I expect this line of code to print
168 but prints 0 instead.
not only that but more behavior follows that makes me question if this
even does what I think it does…
for(int i = 0;i<256;i++)
{
cout<<(int)img->format->palette->colors[i].r<<"
"<<(int)img->format->palette->colors[i].g<<"
"<<(int)img->format->palette->colors[i].b;
cout<<endl;
}
resulted with very unexpected results
r g b //starting with colors[0]
0 0 0
0 0 85
0 0 170
0 0 255
0 36 0
0 36 85
0 36 170
0 36 255
0 73 0
0 73 85
0 73 170
0 73 255
0 109 0
0 109 85
0 109 170
0 109 255
0 146 0
0 146 85
0 146 170
0 146 255
0 182 0
0 182 85
0 182 170
0 182 255
0 219 0
0 219 85
0 219 170
0 219 255
0 255 0
0 255 85
0 255 170
0 255 255
36 0 0
36 0 85
36 0 170
36 0 255
36 36 0
36 36 85
36 36 170
36 36 255
36 73 0
36 73 85
36 73 170
36 73 255
36 109 0
36 109 85
36 109 170
36 109 255
36 146 0
36 146 85
36 146 170
36 146 255
36 182 0
36 182 85
36 182 170
36 182 255
36 219 0
36 219 85
36 219 170
36 219 255
36 255 0
36 255 85
36 255 170
36 255 255
73 0 0
73 0 85
73 0 170
73 0 255
73 36 0
73 36 85
73 36 170
73 36 255
73 73 0
73 73 85
73 73 170
73 73 255
73 109 0
73 109 85
73 109 170
73 109 255
73 146 0
73 146 85
73 146 170
73 146 255
73 182 0
73 182 85
73 182 170
73 182 255
73 219 0
73 219 85
73 219 170
73 219 255
73 255 0
73 255 85
73 255 170
73 255 255
109 0 0
109 0 85
109 0 170
109 0 255
109 36 0
109 36 85
109 36 170
109 36 255
109 73 0
109 73 85
109 73 170
109 73 255
109 109 0
109 109 85
109 109 170
109 109 255
109 146 0
109 146 85
109 146 170
109 146 255
109 182 0
109 182 85
109 182 170
109 182 255
109 219 0
109 219 85
109 219 170
109 219 255
109 255 0
109 255 85
109 255 170
109 255 255
146 0 0
146 0 85
146 0 170
146 0 255
146 36 0
146 36 85
146 36 170
146 36 255
146 73 0
146 73 85
146 73 170
146 73 255
146 109 0
146 109 85
146 109 170
146 109 255
146 146 0
146 146 85
146 146 170
146 146 255
146 182 0
146 182 85
146 182 170
146 182 255
146 219 0
146 219 85
146 219 170
146 219 255
146 255 0
146 255 85
146 255 170
146 255 255
182 0 0
182 0 85
182 0 170
182 0 255
182 36 0
182 36 85
182 36 170
182 36 255
182 73 0
182 73 85
182 73 170
182 73 255
182 109 0
182 109 85
182 109 170
182 109 255
182 146 0
182 146 85
182 146 170
182 146 255
182 182 0
182 182 85
182 182 170
182 182 255
182 219 0
182 219 85
182 219 170
182 219 255
182 255 0
182 255 85
182 255 170
182 255 255
219 0 0
219 0 85
219 0 170
219 0 255
219 36 0
219 36 85
219 36 170
219 36 255
219 73 0
219 73 85
219 73 170
219 73 255
219 109 0
219 109 85
219 109 170
219 109 255
219 146 0
219 146 85
219 146 170
219 146 255
219 182 0
219 182 85
219 182 170
219 182 255
219 219 0
219 219 85
219 219 170
219 219 255
219 255 0
219 255 85
219 255 170
219 255 255
255 0 0
255 0 85
255 0 170
255 0 255
255 36 0
255 36 85
255 36 170
255 36 255
255 73 0
255 73 85
255 73 170
255 73 255
255 109 0
255 109 85
255 109 170
255 109 255
255 146 0
255 146 85
255 146 170
255 146 255
255 182 0
255 182 85
255 182 170
255 182 255
255 219 0
255 219 85
255 219 170
255 219 255
255 255 0
255 255 85
255 255 170
255 255 255
and these values don’t resemble the colors in my bitmap at all because
for one thing I specificaly remember having a bunch (like 50) of the
colors in the middle of the palette just be black, 0, 0, 0
and actually was similar when I tried doing it to a suface pointer I
call screen.
screen->format etc…
which points to my window I guess(screen = setvideomode(etc))
r g b
0 0 0
0 0 85
0 0 170
0 0 255
0 36 0
0 36 85
0 36 170
0 36 255
0 73 0
0 73 85
0 73 170
0 73 255
0 109 0
0 109 85
0 109 170
0 109 255
0 146 0
0 146 85
0 146 170
0 146 255
0 182 0
0 182 85
0 182 170
0 182 255
0 219 0
0 219 85
0 219 170
0 219 255
0 255 0
0 255 85
0 255 170
0 255 255
36 0 0
36 0 85
36 0 170
36 0 255
36 36 0
36 36 85
36 36 170
36 36 255
36 73 0
36 73 85
36 73 170
36 73 255
36 109 0
36 109 85
36 109 170
36 109 255
36 146 0
36 146 85
36 146 170
36 146 255
36 182 0
36 182 85
36 182 170
36 182 255
36 219 0
36 219 85
36 219 170
36 219 255
36 255 0
36 255 85
36 255 170
36 255 255
73 0 0
73 0 85
73 0 170
73 0 255
73 36 0
73 36 85
73 36 170
73 36 255
73 73 0
73 73 85
73 73 170
73 73 255
73 109 0
73 109 85
73 109 170
73 109 255
73 146 0
73 146 85
73 146 170
73 146 255
73 182 0
73 182 85
73 182 170
73 182 255
73 219 0
73 219 85
73 219 170
73 219 255
73 255 0
73 255 85
73 255 170
73 255 255
109 0 0
109 0 85
109 0 170
109 0 255
109 36 0
109 36 85
109 36 170
109 36 255
109 73 0
109 73 85
109 73 170
109 73 255
109 109 0
109 109 85
109 109 170
109 109 255
109 146 0
109 146 85
109 146 170
109 146 255
109 182 0
109 182 85
109 182 170
109 182 255
109 219 0
109 219 85
109 219 170
109 219 255
109 255 0
109 255 85
109 255 170
109 255 255
146 0 0
146 0 85
146 0 170
146 0 255
146 36 0
146 36 85
146 36 170
146 36 255
146 73 0
146 73 85
146 73 170
146 73 255
146 109 0
146 109 85
146 109 170
146 109 255
146 146 0
146 146 85
146 146 170
146 146 255
146 182 0
146 182 85
146 182 170
146 182 255
146 219 0
146 219 85
146 219 170
146 219 255
146 255 0
146 255 85
146 255 170
146 255 255
182 0 0
182 0 85
182 0 170
182 0 255
182 36 0
182 36 85
182 36 170
182 36 255
182 73 0
182 73 85
182 73 170
182 73 255
182 109 0
182 109 85
182 109 170
182 109 255
182 146 0
182 146 85
182 146 170
182 146 255
182 182 0
182 182 85
182 182 170
182 182 255
182 219 0
182 219 85
182 219 170
182 219 255
182 255 0
182 255 85
182 255 170
182 255 255
219 0 0
219 0 85
219 0 170
219 0 255
219 36 0
219 36 85
219 36 170
219 36 255
219 73 0
219 73 85
219 73 170
219 73 255
219 109 0
219 109 85
219 109 170
219 109 255
219 146 0
219 146 85
219 146 170
219 146 255
219 182 0
219 182 85
219 182 170
219 182 255
219 219 0
219 219 85
219 219 170
219 219 255
219 255 0
219 255 85
219 255 170
219 255 255
255 0 0
255 0 85
255 0 170
255 0 255
255 36 0
255 36 85
255 36 170
255 36 255
255 73 0
255 73 85
255 73 170
255 73 255
255 109 0
255 109 85
255 109 170
255 109 255
255 146 0
255 146 85
255 146 170
255 146 255
255 182 0
255 182 85
255 182 170
255 182 255
255 219 0
255 219 85
255 219 170
255 219 255
255 255 0
255 255 85
255 255 170
255 255 255
So now these results make me consider if I even accurately accessed my images palette, or if something is in the way of that, or if its not even supposed to do what it looks like it should do.
this feels like some sort of default palette where the color spectrum is represented as squarely as possible and I’m trying to get the palette of a specific image to show.
If there is more information I could reveal you think would be helpful in ascertaining the problem please let me know, thank you_________________________________________________________________
Hotmail has tools for the New Busy. Search, chat and e-mail from your inbox.
http://www.windowslive.com/campaign/thenewbusy?ocid=PID28326::T:WLMTAGL:ON:WL:en-US:WM_HMP:042010_1
