Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.forth > #19561

Re: 3D-graphics calculations using integers?

From rickman <gnuarm@gmail.com>
Newsgroups comp.lang.forth
Subject Re: 3D-graphics calculations using integers?
Date 2013-02-08 17:20 -0500
Organization A noiseless patient Spider
Message-ID <kf3tmm$dpu$1@dont-email.me> (permalink)
References (1 earlier) <kf1cu9$359$2@dont-email.me> <slrnkh8hr0.bdj.zbigniew2011REMOVE@Tichy.myhome.org> <slrnkh8iat.br9.zbigniew2011REMOVE@Tichy.myhome.org> <kf1ela$m7h$3@dont-email.me> <slrnkh9rsm.7ia.zbigniew2011REMOVE@Tichy.myhome.org>

Show all headers | View raw

On 2/8/2013 6:28 AM, Zbiggy wrote:
> In comp.lang.forth, rickman wrote:
>
>> What exactly are you doing?  Usually the data is only transformed to be
>> displayed.  As long as your data is accurate, the transform can be "good
>> enough" for display.
>
> Yes, but when talking about compound calculation, pay attention, that
> rotation matrices use trigonometrical functions. How should I calculate
> sin, cos etc. without involving fractions?

There are many ways of calculating trig functions in fixed point.  None 
that I know of require the use of "fractions".  The main thing you need 
to realize is that your calculations will have a certain amount of 
precision that has to meet your needs.  But I think you are making 
certain assumptions about how these calculations will be done that are 
not the best way to do it.  For example one of your other posts are 
saying that every time you change the orientation of an object the 
object itself loses precision.  If you separate the definition of the 
object data from the transformation data you will never lose precision 
of the object.  How the transformation data retains precision is up to 
your application.

Are you aware that you can used fixed point arithmetic rather than 
integer?

How are you thinking the calculations will be done?

Please don't assume that using floating point will solve any problems 
you may or may not have.  Every floating point calculation involves a 
final rounding operation so that the result can be stored back into the 
limited precision of the format being used.  As I said before, floating 
point has *less* precision when using the same number of bits.

BTW, "pay attention" is a bit rude to say to someone who is trying to 
help you.  If you aren't interested in the help, just don't reply.  If 
you want the help, don't be rude.

-- 

Rick

Back to comp.lang.forth | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

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

csiph-web