RE: [AD] Question about 256 colors modes

[Hugo Daniel Caro <hugo_caro@xxxxxxxxxx>]

Hi Vincent!

About this "puzzling" palette, this is the way we are
using them:

1- The graphics dude gets all the 54 * 2 images
generated in true color using his creativity.

2- He then create one single image of all of them, and
then he creates the "master" palette.

3- Once created, he then applies this "master palette"
to all the 54 * 2 BMPs to convert the true color
images to indexed colors.

4- We can have palette change on the gaming machine,
but because of a timing issue -it's not a PC, but I
use the same program created with allegro on PC to
test the sprites and graphics-, we prefer to set one
single palette at booting time, for all the 54 BMPs on
one monitor, and eventually a new "master palette" for
the 54 BMPs on the second monitor. 

This "index 0" issue make us add a new step before
applying this "master palette": checking it has the
transparent color (in our case BLACK) at index 0 and
in our proprietary hardware the low level drivers API
does not have this limitation, you can set which color
index is transparent (up to 4 "transparent" colors in
fact).

As you stated, the artist can do this checking and
correct the palette, but my question was to avoid this
specific step.

If the answer from allegro gurus is "too complicated"
or "doesn't worth it", it is ok for me, but when you
are working with a "graphics guru" -in fact he's a
talented illustrator, inbetweener cartoonist and a
large etc.- you try to simplify everybody's life hehe.

Thanks for your answers again!

Kind regards, 

Hugo Caro
Gaming Software Developer


 --- Vincent Penecherc'h
<Vincent.Penecherch@xxxxxxxxxx> escribió:

> > I guess Photoshop is popular enough to find that
> this
> > issue may arise to any other developer. May be a
> > "quick and dirty" solution would be to have a test
> > program that "reorders" the palette so it gets the
> > transparent color wanted (if it's not placed at
> index
> > 0).
> 
> That's what I don't get. You most probably are going
> to
> use more than one image on the screen, so (if your
> screen
> is also 8 bit, and you don't expand on blit) they
> will
> have to have the same palette if you want them to
> appear
> correctly. Therefore, you don't want to have a
> randomly
> generated palette at your gfx program's whim. If
> images
> are authored in 8 bit, then you already know your
> palette
> (the artist built it, or can easily change it). If
> they
> are authored in truecolor, then the quantization
> will
> generate a more or less matching palette, but this
> has
> no reason to be the same for different images, so
> you'll
> have to add some step to make palettes the same for
> all
> images. So I don't see how you end up with a
> generated
> palette. Unless you force all subsequent images to
> be
> quantized to whatever palette is generated by the
> first
> image, or something similar.
> 
> If you see what I mean, I'm thinking I'm not very
> clear
> here, but I'm not sure how to put it more clearly.
> In
> essence, you need to do that palette transform in
> the
> first place anyway, and you don't seem to be doing
> it,
> which is puzzling me.
> 
> 
>
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