Groups > comp.lang.java.programmer > #38979

Re: Game color question, with max 256 colors

Path	csiph.com!eternal-september.org!feeder.eternal-september.org!reader01.eternal-september.org!.POSTED!not-for-mail
From	Andreas Leitgeb <avl@logic.at>
Newsgroups	comp.lang.java.programmer
Subject	Re: Game color question, with max 256 colors
Date	Sun, 2 Jun 2019 14:16:06 -0000 (UTC)
Organization	A noiseless patient Spider
Lines	40
Message-ID	<slrnqf7mh6.cfl.avl@logic.at> (permalink)
References	<qcv1ae$1670$1@gioia.aioe.org>
Reply-To	avl@logic.at
Injection-Date	Sun, 2 Jun 2019 14:16:06 -0000 (UTC)
Injection-Info	reader02.eternal-september.org; posting-host="252c2dfa75f62a4d76b9073d1801dcf0"; logging-data="13464"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+xF04Mkwi87IyMfwYohE6i"
User-Agent	slrn/1.0.3 (Linux)
Cancel-Lock	sha1:ocyVl0g2J8sljYrlJ17tSNVT8Xg=
Xref	csiph.com comp.lang.java.programmer:38979

Show key headers only | View raw

Graeme Geldenhuys <graemeg@example.net> wrote:
> Is there anybody here that can figure this out?
> public class Color {
> 	public static int get(int a, int b, int c, int d) {
> 		return (get(d) << 24) + (get(c) << 16) + (get(b) << 8) + (get(a));
> 	}

This method encodes 4 unsigned 1-byte values in an int. Probably these
4 values are the 4 separate colors to be used for rendering the sprite.
Encoding 4 values into one means that the caller only needs to pass
one value for all four colors. In a serious application, one would use
a class to hold the four independent color attributes.

> 	public static int get(int d) {
> 		if (d < 0) return 255;
> 		int r = d / 100 % 10;
> 		int g = d / 10 % 10;
> 		int b = d % 10;
> 		return r * 36 + g * 6 + b;
> 	}
> }

This method converts values from a "fake base-6" representation
into a binary representation of a "6-shades of each red,green,blue
colorcube."

E.g.:
  555:  5 red, 5 green, 5 blue  - decimal value 5*36 + 5*6 + 5 = 215
  432:  4 red, 3 green, 2 blue  - decimal value 4*36 + 3*6 + 2 = 164

-1 is a special case here, and is encoded as 255, which likely
gets a special treatment lateron.  Maybe it means transparent,
but I don't know, without looking up the relevant part of the
source to see how  screen.render(...) unpacks and uses the
values. That the digits would mean red,green,blue in this order
is just a guess, based on how colors are usually specified.

> 			screen.render(... , Color.get(-1, 555, 555, 555), 0);
>   https://www.twitch.tv/videos/38122415

Thread

Game color question, with max 256 colors Graeme Geldenhuys <graemeg@example.net> - 2019-06-02 00:21 +0100
  Re: Game color question, with max 256 colors Andreas Leitgeb <avl@logic.at> - 2019-06-02 14:16 +0000
    Re: Game color question, with max 256 colors Graeme Geldenhuys <graemeg@example.net> - 2019-06-05 17:53 +0100

csiph-web