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Groups > comp.lang.forth > #19542

Re: 3D-graphics calculations using integers?

Date 2013-02-07 16:38 -1000
From "Elizabeth D. Rather" <erather@forth.com>
Organization FORTH, Inc.
Newsgroups comp.lang.forth
Subject Re: 3D-graphics calculations using integers?
References <slrnkh8c16.67i.zbigniew2011REMOVE@Tichy.myhome.org> <9e137ba3-0354-42bf-a992-98dd01c69458@googlegroups.com> <slrnkh8f7g.92c.zbigniew2011REMOVE@Tichy.myhome.org>
Message-ID <wdadnTKsmLLe-InMnZ2dnUVZ_vSdnZ2d@supernews.com> (permalink)

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On 2/7/13 12:46 PM, Zbiggy wrote:
> In comp.lang.forth, Pablo Hugo Reda wrote:
>
>> I use fixed point for 3d graphics, work very well.
>> I use 32 bits integer then use 16 bits por integer part and 16 bits for
>> fractional..one cell for number.
>
> But how do you represent the fraction? Not as "simple fraction"?
>
> The second problem is: I'm going to use DX-Forth for DOS. Therefore I won't
> have 32 bits cells.
>

What's a "fraction"? Your application has a certain intrinsic level of 
accuracy in its original data. For example, if your measurements are 
accurate to 1 mm then you can work in tenths of millimeters. Just don't 
think of them as "fractions of a meter", although you may represent them 
that way on the screen or page.

When you do an operation in floating point, you can represent the result 
with many decimal places. but that doesn't mean your numbers are actual 
accurate to all those decimal places. It behooves all of us to keep 
track of how much real resolution we have on our numbers.

And why can't you use a Forth that has the facilities you need?

Cheers,
Elizabeth

-- 
==================================================
Elizabeth D. Rather   (US & Canada)   800-55-FORTH
FORTH Inc.                         +1 310.999.6784
5959 West Century Blvd. Suite 700
Los Angeles, CA 90045
http://www.forth.com

"Forth-based products and Services for real-time
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Thread

3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-07 22:51 +0100
  Re: 3D-graphics calculations using integers? "Paul E. Bennett" <Paul_E.Bennett@topmail.co.uk> - 2013-02-07 22:08 +0000
  Re: 3D-graphics calculations using integers? AKE <assadebrahim2000@gmail.com> - 2013-02-07 14:32 -0800
    Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-07 23:40 +0100
      Re: 3D-graphics calculations using integers? AKE <assadebrahim2000@gmail.com> - 2013-02-07 17:06 -0800
      Re: 3D-graphics calculations using integers? AKE <assadebrahim2000@gmail.com> - 2013-02-07 17:07 -0800
  Re: 3D-graphics calculations using integers? Pablo Hugo Reda <pabloreda@gmail.com> - 2013-02-07 14:36 -0800
    Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-07 23:46 +0100
      Re: 3D-graphics calculations using integers? "Elizabeth D. Rather" <erather@forth.com> - 2013-02-07 16:38 -1000
        Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 10:22 +0100
      Re: 3D-graphics calculations using integers? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-08 10:26 +0000
  Re: 3D-graphics calculations using integers? "Elizabeth D. Rather" <erather@forth.com> - 2013-02-07 12:50 -1000
    Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 00:15 +0100
      Re: 3D-graphics calculations using integers? kenney@cix.compulink.co.uk - 2013-02-08 14:51 -0600
        Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 22:02 +0100
  Re: 3D-graphics calculations using integers? rickman <gnuarm@gmail.com> - 2013-02-07 18:21 -0500
    Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 00:30 +0100
      Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 00:39 +0100
        Re: 3D-graphics calculations using integers? rickman <gnuarm@gmail.com> - 2013-02-07 18:51 -0500
          Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 12:28 +0100
            Re: 3D-graphics calculations using integers? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-08 12:25 +0000
              Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 22:04 +0100
                Re: 3D-graphics calculations using integers? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-09 15:27 +0000
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-09 16:36 +0100
            Re: 3D-graphics calculations using integers? Mark Wills <forthfreak@gmail.com> - 2013-02-08 05:01 -0800
              Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 21:58 +0100
            Re: 3D-graphics calculations using integers? Roberto Waltman <usenet@rwaltman.com> - 2013-02-08 10:08 -0500
              Re: 3D-graphics calculations using integers? Roberto Waltman <usenet@rwaltman.com> - 2013-02-08 10:11 -0500
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 22:05 +0100
              Re: 3D-graphics calculations using integers? Pablo Hugo Reda <pabloreda@gmail.com> - 2013-02-08 08:29 -0800
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 18:48 +0100
            Re: 3D-graphics calculations using integers? rickman <gnuarm@gmail.com> - 2013-02-08 17:20 -0500
              Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-08 23:32 +0100
                Re: 3D-graphics calculations using integers? rickman <gnuarm@gmail.com> - 2013-02-09 23:57 -0500
              Re: 3D-graphics calculations using integers? "Elizabeth D. Rather" <erather@forth.com> - 2013-02-08 15:02 -1000
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-09 02:24 +0100
                Re: 3D-graphics calculations using integers? "Elizabeth D. Rather" <erather@forth.com> - 2013-02-08 15:58 -1000
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-09 16:43 +0100
                Re: 3D-graphics calculations using integers? "Elizabeth D. Rather" <erather@forth.com> - 2013-02-09 10:03 -1000
                Re: 3D-graphics calculations using integers? "Ed" <invalid@nospam.com> - 2013-02-10 11:35 +1100
                Re: 3D-graphics calculations using integers? humptydumpty <ouatubi@gmail.com> - 2013-02-08 23:48 -0800
                Re: 3D-graphics calculations using integers? Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-09 16:37 +0100
                OT: ANS Forth Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-09 17:27 +0100
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-09 10:06 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-09 12:26 -0800
                Re: OT: ANS Forth Elizabeth D Rather <erather@forth.com> - 2013-02-09 14:38 -1000
                Re: OT: ANS Forth "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2013-02-22 12:52 -0500
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-22 09:25 -1000
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-10 08:15 -0600
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-10 23:34 -0800
                Re: OT: ANS Forth Josh Grams <josh@qualdan.com> - 2013-02-11 22:14 +0000
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-11 13:34 -1000
                Re: OT: ANS Forth "Ed" <invalid@nospam.com> - 2013-02-11 11:52 +1100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-10 17:11 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-10 22:06 -1000
                Re: OT: ANS Forth "Charles Childers" <crc@retroforth.org> - 2013-02-11 17:17 -0500
                Re: OT: ANS Forth "Ed" <invalid@nospam.com> - 2013-02-13 11:42 +1100
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-12 16:07 -1000
                Re: OT: ANS Forth "Ed" <invalid@nospam.com> - 2013-02-15 09:42 +1100
                Re: OT: ANS Forth Zbiggy <zbigniew2011REMOVE@gmail.REMOVE.com> - 2013-02-15 00:16 +0100
                Re: OT: ANS Forth "Ed" <invalid@nospam.com> - 2013-02-17 16:05 +1100
                Re: OT: ANS Forth Howerd <howerdo@yahoo.co.uk> - 2013-02-17 04:16 -0800
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-17 13:12 +0000
                Re: OT: ANS Forth Howerd <howerdo@yahoo.co.uk> - 2013-02-17 09:15 -0800
                Re: OT: ANS Forth Brad Eckert <hwfwguy@gmail.com> - 2013-02-19 09:35 -0800
                Re: OT: ANS Forth Andy Valencia <user@vsta.org> - 2013-02-19 19:25 +0000
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-19 15:35 -0600
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 00:37 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-20 23:07 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 01:38 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-21 08:50 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 15:44 -0800
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-24 03:41 +0000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 20:00 -0800
                Re: OT: ANS Forth stephenXXX@mpeforth.com (Stephen Pelc) - 2013-02-24 13:49 +0000
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-24 15:04 +0000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-24 14:52 -0800
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-24 23:51 +0000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-24 16:23 -0800
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-21 03:55 -0600
                Re: OT: ANS Forth "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2013-02-22 13:01 -0500
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-22 12:26 -0600
                Re: OT: ANS Forth Andy Valencia <user@vsta.org> - 2013-02-19 21:54 +0000
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-19 18:21 -0600
                Re: OT: ANS Forth Brad Eckert <hwfwguy@gmail.com> - 2013-02-20 08:45 -0800
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-20 11:01 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-20 11:25 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 00:22 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-20 22:50 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 01:08 -0800
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-21 12:42 +0000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-21 13:50 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 09:36 -0800
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-22 01:32 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 00:50 -0800
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-24 03:03 +0100
                Re: OT: ANS Forth Brad Eckert <hwfwguy@gmail.com> - 2013-02-21 09:12 -0800
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 00:38 -0800
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-21 09:01 -1000
                Re: OT: ANS Forth mhx@iae.nl (Marcel Hendrix) - 2013-02-22 00:05 +0200
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-21 13:24 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-21 09:33 -0800
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-21 13:04 -0600
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-22 01:41 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 00:31 -0800
                Re: OT: ANS Forth "Paul E. Bennett" <Paul_E.Bennett@topmail.co.uk> - 2013-02-23 09:15 +0000
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-23 04:33 -0600
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-23 13:49 +0000
                Re: OT: ANS Forth Roberto Waltman <usenet@rwaltman.com> - 2013-02-23 13:35 -0500
                Re: OT: ANS Forth Roberto Waltman <usenet@rwaltman.com> - 2013-02-23 13:46 -0500
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 15:26 -0800
                Re: OT: ANS Forth Roberto Waltman <usenet@rwaltman.com> - 2013-02-24 09:41 -0500
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-21 09:09 -1000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 00:37 -0800
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-23 13:57 +0000
                Re: OT: ANS Forth "Elizabeth D. Rather" <erather@forth.com> - 2013-02-23 08:47 -1000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-22 01:27 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 00:16 -0800
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-23 04:36 -0600
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-23 16:52 +0000
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-23 12:39 -0800
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-25 16:27 +0000
                Re: OT: ANS Forth "Rod Pemberton" <do_not_have@notemailnotz.cnm> - 2013-02-23 18:08 -0500
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-24 02:20 +0100
                Re: OT: ANS Forth Paul Rubin <no.email@nospam.invalid> - 2013-02-24 20:16 -0800
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-25 16:04 +0100
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-25 17:12 +0000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-25 20:44 +0100
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-25 16:45 +0100
                Re: OT: ANS Forth Andy Valencia <user@vsta.org> - 2013-02-24 02:09 +0000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-24 04:03 +0100
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-25 17:58 +0000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-02-25 20:57 +0100
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-03-02 16:43 +0000
                Re: OT: ANS Forth Bernd Paysan <bernd.paysan@gmx.de> - 2013-03-02 18:14 +0100
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-03-03 13:56 +0000
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-24 03:45 -0600
                Re: OT: ANS Forth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-13 04:12 -0600
                Re: OT: ANS Forth stephenXXX@mpeforth.com (Stephen Pelc) - 2013-02-13 12:24 +0000
                Re: OT: ANS Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-02-11 14:41 +0000
                Re: OT: ANS Forth Andy Valencia <user@vsta.org> - 2013-02-11 19:44 +0000
                Re: OT: ANS Forth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-02-11 21:14 +0000
                Re: 3D-graphics calculations using integers? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-02-09 18:14 -0600
                Re: 3D-graphics calculations using integers? rickman <gnuarm@gmail.com> - 2013-02-10 00:06 -0500

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