Java-Gaming.org    
Featured games (81)
games approved by the League of Dukes
Games in Showcase (497)
Games in Android Showcase (114)
games submitted by our members
Games in WIP (563)
games currently in development
News: Read the Java Gaming Resources, or peek at the official Java tutorials
 
    Home     Help   Search   Login   Register   
Pages: [1]
  ignore  |  Print  
  Java bytes -128...+127 vs. normal byte range issue  (Read 1234 times)
0 Members and 1 Guest are viewing this topic.
Offline ameano

Senior Newbie




abstract void


« Posted 2005-02-08 09:08:15 »

Hi All

Ok, say for example we use a tile map editor such as mappy (www.tilemap.co.uk) to create a map file for a game. The range of tiles we have can be anything from 0..255, i.e. a standard byte.

The standard byte in java has a range from -128..127. Can this cause any issues and is there anyway to deal with this?

Also I would like to know how an Image deals with RGB values for every pixel. maybe they are short or int values but that takes up too much space, (of course we can always use colour pallettes) so if we want to use a byte for each value and the max range is only 128 we will have some problems... what is the actual implementation?

unless of course we convert the negative numbers to their positive counterparts using some bit operations...

any thoughts / suggestions / solutions are most welcome. Also is this actually a problem you may have come accross in developing your games or is it really not a cause for concern?

Thanks

Ameano
rules are there to be broken... same goes for the rules of programming classes in j2me
Offline shmoove

Junior Member




Doh!


« Reply #1 - Posted 2005-02-08 11:39:47 »

Quote

The standard byte in java has a range from -128..127. Can this cause any issues and is there anyway to deal with this?

In memory 255 looks the same as -1, and 128 looks like -128. It all depends on how the value is interpreted. As long as you are aware of this you can deal with any issues that might arise.

Quote

Also I would like to know how an Image deals with RGB values for every pixel. maybe they are short or int values but that takes up too much space, (of course we can always use colour pallettes) so if we want to use a byte for each value and the max range is only 128 we will have some problems... what is the actual implementation?

This is device specific. It depends on the actual hardware and the decisions the implementors of the KVM took. The most common approach is having RGB values stored in the smallest amount of memory that can handle all the available colors. The maximum value of 128 is a non-issue since this stuff is implemented natively and not in Java.

Quote

unless of course we convert the negative numbers to their positive counterparts using some bit operations...

1  
2  
3  
4  
byte b = (byte)255;
System.out.println("b=" + b);
int i = (int)b & 0xff;
System.out.println("i=" + i);


Quote

any thoughts / suggestions / solutions are most welcome. Also is this actually a problem you may have come accross in developing your games or is it really not a cause for concern?

Thanks

If you understand what's going on behind the scenes (ie, in the memory), then no issue that this arises will become a showstopper. I hope this response helps you achieve that understanding.

shmoove
Pages: [1]
  ignore  |  Print  
 
 
You cannot reply to this message, because it is very, very old.

 

Add your game by posting it in the WIP section,
or publish it in Showcase.

The first screenshot will be displayed as a thumbnail.

BurntPizza (25 views)
2014-09-19 03:14:18

Dwinin (39 views)
2014-09-12 09:08:26

Norakomi (68 views)
2014-09-10 13:57:51

TehJavaDev (93 views)
2014-09-10 06:39:09

Tekkerue (47 views)
2014-09-09 02:24:56

mitcheeb (68 views)
2014-09-08 06:06:29

BurntPizza (51 views)
2014-09-07 01:13:42

Longarmx (38 views)
2014-09-07 01:12:14

Longarmx (44 views)
2014-09-07 01:11:22

Longarmx (40 views)
2014-09-07 01:10:19
List of Learning Resources
by Longor1996
2014-08-16 10:40:00

List of Learning Resources
by SilverTiger
2014-08-05 19:33:27

Resources for WIP games
by CogWheelz
2014-08-01 16:20:17

Resources for WIP games
by CogWheelz
2014-08-01 16:19:50

List of Learning Resources
by SilverTiger
2014-07-31 16:29:50

List of Learning Resources
by SilverTiger
2014-07-31 16:26:06

List of Learning Resources
by SilverTiger
2014-07-31 11:54:12

HotSpot Options
by dleskov
2014-07-08 01:59:08
java-gaming.org is not responsible for the content posted by its members, including references to external websites, and other references that may or may not have a relation with our primarily gaming and game production oriented community. inquiries and complaints can be sent via email to the info‑account of the company managing the website of java‑gaming.org
Powered by MySQL Powered by PHP Powered by SMF 1.1.18 | SMF © 2013, Simple Machines | Managed by Enhanced Four Valid XHTML 1.0! Valid CSS!