Re: harder case for optimization

From	BartC <bc@freeuk.com>
Newsgroups	comp.lang.c
Subject	Re: harder case for optimization
References	(1 earlier) <cb55e90d-5aaa-4ca7-aeaa-b12e21f53877@googlegroups.com> <sIiew.50101$Au7.15036@fx28.am4> <0f03adc7-bf74-46e7-b4d0-1852b593676d@googlegroups.com> <gXmew.37078$bC1.32801@fx34.am4> <b83f7f73-1668-4561-b4df-1737de512ed0@googlegroups.com>
Message-ID	<3uqew.18552$MP5.1788@fx35.am4> (permalink)
Organization	virginmedia.com
Date	2014-11-29 21:00 +0000

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On 29/11/2014 18:55, Malcolm McLean wrote:
> On Saturday, November 29, 2014 4:59:01 PM UTC, Bart wrote:

>> In such a system, a
>> sphere is represented by a wireframe network of vertices and faces,
>> where you can reduce the number of faces to make it faster, at a cost of
>> reducing apparent roundness.
>>
>> But the advantage is that most of the work needed in rendering such
>> objects can be taken care of with libraries such as OpenGL (and
>> DirectX), which can also make use of special graphics hardware.
>>
> Whilst those are, in a sense, vector graphics, that's not how the
> term is usually used.

> 3D systems usually use polygon models which are transformed from
> 3D space to screen space at a late stage in rendering. Curves can't
> be represented, but there are various cheats to make polygonal
> approximations of curved surfaces look more continuous. You can
> however represent curves exactly and do the calculations properly,
> which seems to be fir's approach. They're both technically vector
> graphics,

I'm not sure if anyone knows exactly what fir is doing. From the 
snippets of code I've seen, and from the demo, he might have a model 
that stores the centres of spheres and their radii. But then it appears 
this is directly rendered into the pixels that have to represent the 
sphere, depending on the viewpoint and lighting model. (With the 
background being another task to do.)

If the application will only ever deal with spheres, then it might as 
well stay like this (and maybe there are libraries that work solely with 
spheres). (It's not clear if he's testing bounding boxes/spheres in his 
code. If not that's another speedup technique.)

By vector graphics I mean having an intermediate step where the spheres 
exist as some 3D surface in a format favoured by libraries such as 
OpenGL. The main advantage is being to offload most of the work. Also 
the library might be able to use any hardware acceleration that is 
available. The end result is that transformable 3D data is being 
processed this side of the library, not pixels apart from the ones in 
any texture maps that are used.

-- 
Bartc

Thread

harder case for optimization fir <profesor.fir@gmail.com> - 2014-11-27 00:42 -0800
  Re: harder case for optimization "BartC" <bc@freeuk.com> - 2014-11-27 11:34 +0000
    Re: harder case for optimization David Brown <david.brown@hesbynett.no> - 2014-11-27 13:29 +0100
    Re: harder case for optimization Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-11-27 05:58 -0800
      Re: harder case for optimization Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-11-27 06:36 -0800
    Re: harder case for optimization fir <profesor.fir@gmail.com> - 2014-11-27 12:26 -0800
  Re: harder case for optimization "BartC" <bc@freeuk.com> - 2014-11-27 22:07 +0000
    Re: harder case for optimization fir <profesor.fir@gmail.com> - 2014-11-27 14:49 -0800
      Re: harder case for optimization "BartC" <bc@freeuk.com> - 2014-11-28 00:05 +0000
    Re: harder case for optimization David Brown <david.brown@hesbynett.no> - 2014-11-28 00:46 +0100
      Re: harder case for optimization "BartC" <bc@freeuk.com> - 2014-11-28 00:55 +0000
        Re: harder case for optimization David Brown <david.brown@hesbynett.no> - 2014-11-28 07:20 +0100
          Re: harder case for optimization Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-11-28 00:41 -0800
            Re: harder case for optimization fir <profesor.fir@gmail.com> - 2014-11-28 01:54 -0800
              Re: harder case for optimization Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-11-28 02:19 -0800
                Re: harder case for optimization fir <profesor.fir@gmail.com> - 2014-11-28 04:05 -0800
                Closed captioning (Was: harder case for something or other) gazelle@shell.xmission.com (Kenny McCormack) - 2014-11-28 12:15 +0000
                Re: harder case for optimization fir <profesor.fir@gmail.com> - 2014-11-28 06:11 -0800
              Re: harder case for optimization gazelle@shell.xmission.com (Kenny McCormack) - 2014-11-28 12:18 +0000
                Re: harder case for optimization fir <profesor.fir@gmail.com> - 2014-11-28 04:42 -0800
                Re: harder case for optimization gazelle@shell.xmission.com (Kenny McCormack) - 2014-11-28 16:37 +0000
                Re: harder case for optimization fir <profesor.fir@gmail.com> - 2014-11-28 08:48 -0800
                Re: harder case for optimization Kaz Kylheku <kaz@kylheku.com> - 2014-11-28 16:51 +0000
                Re: harder case for optimization fir <profesor.fir@gmail.com> - 2014-11-28 10:38 -0800
            Re: harder case for optimization David Brown <david.brown@hesbynett.no> - 2014-11-28 11:34 +0100
          Re: harder case for optimization "BartC" <bc@freeuk.com> - 2014-11-28 11:21 +0000
            Re: harder case for optimization fir <profesor.fir@gmail.com> - 2014-11-28 04:23 -0800
            Re: harder case for optimization David Brown <david.brown@hesbynett.no> - 2014-11-28 13:58 +0100
              Re: harder case for optimization "BartC" <bc@freeuk.com> - 2014-11-28 13:46 +0000
                Re: harder case for optimization David Brown <david.brown@hesbynett.no> - 2014-11-28 16:25 +0100
                Re: harder case for optimization fir <profesor.fir@gmail.com> - 2014-11-28 08:18 -0800
                Re: harder case for optimization David Brown <david.brown@hesbynett.no> - 2014-11-28 20:17 +0100
                Re: harder case for optimization Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-11-28 08:54 -0800
                Re: harder case for optimization David Brown <david.brown@hesbynett.no> - 2014-11-28 20:22 +0100
                Re: harder case for optimization Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-11-28 11:29 -0800
                Re: harder case for optimization Kaz Kylheku <kaz@kylheku.com> - 2014-11-28 19:51 +0000
                Re: harder case for optimization David Brown <david.brown@hesbynett.no> - 2014-11-28 20:58 +0100
                Re: harder case for optimization Melzzzzz <mel@zzzzz.com> - 2014-11-28 21:03 +0100
                Re: harder case for optimization Kaz Kylheku <kaz@kylheku.com> - 2014-11-28 20:11 +0000
                Re: harder case for optimization Melzzzzz <mel@zzzzz.com> - 2014-11-28 21:31 +0100
                Re: harder case for optimization "BartC" <bc@freeuk.com> - 2014-11-28 20:06 +0000
                Re: harder case for optimization "BartC" <bc@freeuk.com> - 2014-11-28 17:14 +0000
                Re: harder case for optimization David Brown <david.brown@hesbynett.no> - 2014-11-28 20:54 +0100
                Re: harder case for optimization "BartC" <bc@freeuk.com> - 2014-11-28 20:16 +0000
                Re: harder case for optimization David Brown <david.brown@hesbynett.no> - 2014-11-28 21:56 +0100
        Re: harder case for optimization fir <profesor.fir@gmail.com> - 2014-11-27 23:37 -0800
          Re: harder case for optimization fir <profesor.fir@gmail.com> - 2014-11-27 23:54 -0800
          Re: harder case for optimization BartC <bc@freeuk.com> - 2014-11-28 11:01 +0000
            Re: harder case for optimization fir <profesor.fir@gmail.com> - 2014-11-28 23:52 -0800
              Re: harder case for optimization Morris Dovey <mrdovey@iedu.com> - 2014-11-29 02:03 -0600
                Re: harder case for optimization fir <profesor.fir@gmail.com> - 2014-11-29 00:38 -0800
  Re: harder case for optimization fir <profesor.fir@gmail.com> - 2014-11-29 03:12 -0800
    Re: harder case for optimization BartC <bc@freeuk.com> - 2014-11-29 12:09 +0000
      Re: harder case for optimization fir <profesor.fir@gmail.com> - 2014-11-29 04:18 -0800
      Re: harder case for optimization fir <profesor.fir@gmail.com> - 2014-11-29 05:22 -0800
        Re: harder case for optimization BartC <bc@freeuk.com> - 2014-11-29 16:58 +0000
          Re: harder case for optimization fir <profesor.fir@gmail.com> - 2014-11-29 09:35 -0800
          Re: harder case for optimization Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-11-29 10:55 -0800
            Re: harder case for optimization BartC <bc@freeuk.com> - 2014-11-29 21:00 +0000
              Re: harder case for optimization Ian Collins <ian-news@hotmail.com> - 2014-11-30 11:25 +1300
                Re: harder case for optimization BartC <bc@freeuk.com> - 2014-11-29 22:56 +0000
                Re: harder case for optimization Ian Collins <ian-news@hotmail.com> - 2014-11-30 12:00 +1300
                Re: harder case for optimization fir <profesor.fir@gmail.com> - 2014-11-29 16:01 -0800
                Re: harder case for optimization fir <profesor.fir@gmail.com> - 2014-11-29 16:21 -0800
                Re: harder case for optimization fir <profesor.fir@gmail.com> - 2014-11-29 16:52 -0800
                Re: harder case for optimization fir <profesor.fir@gmail.com> - 2014-11-29 17:14 -0800
            Re: harder case for optimization glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2014-11-30 00:20 +0000
              Re: harder case for optimization Malcolm McLean <malcolm.mclean5@btinternet.com> - 2014-11-29 16:43 -0800
        Re: harder case for optimization Kaz Kylheku <kaz@kylheku.com> - 2014-11-29 17:29 +0000
  Re: harder case for optimization fir <profesor.fir@gmail.com> - 2014-12-05 02:12 -0800

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