basic implementation for isosurface, isocolors, isonormals

[Daniel J Sebald]

David Bateman wrote:
> Thomas Treichl wrote:
> 
>> David Bateman schrieb:
>>
>>> Thomas Treichl wrote:
>>>
>>>> David Bateman schrieb:
>>>>
>>>>> I don't think the hiding of the axis is a really major issue though 
>>>>> I also see some other artifacts that seem to be due to some weird 
>>>>> issue in gnuplot with the depthorder, and I don't see the fix for 
>>>>> it at the moment. Also it appears that FaceVertexCdata is not 
>>>>> really implemented yet and so these values aren't respected at all. 
>>>>> In fact the patch properties have a number of derived properties 
>>>>> that should be treated specially, like the differences between the 
>>>>> [xyz]data and vertices and faces data.. The derivation of one of 
>>>>> these properties from another is currently handled in the patch 
>>>>> function itself.. However this doesn't make sense as then if the 
>>>>> user uses the "set" function to change one of these properties the 
>>>>> others won't be changed appropriately..
>>>>>
>>>>> The way to fix it is either to treat the issue in the set/get 
>>>>> methods of the patch type or to add callbacks in the patch 
>>>>> functions.. Callbacks are probably the easiest method as we can 
>>>>> stay in the scripting language.. I'll look at this as I'm 
>>>>> interested in getting the iso* functions into Octave..
>>>>
>>>>
>>>> Hi,
>>>>
>>>> I just wanted to know, what the final maintainers' decision about 
>>>> inclusion of the iso* into the core Octave sources is? I think that 
>>>> I can work on creating a changeset because I don't want these codes 
>>>> get forgotten...
>>>>
>>>> If you say you currently can't decide or you think it is better to 
>>>> not include the files right now or whatever then I think we should 
>>>> at least host Martin's functions at OF right now?
>>>
>>> I'm working on rewriting the __patch__ to add listeners such that 
>>> changes to the {x|y|z|c}data properties also changes the faces, 
>>> vertices and facevertexcdata properties appropriately. Without this 
>>> the previous code was buggy and so not of a quality to be included in 
>>> Octave.. In fact I have most of this going now and hopefully will 
>>> send something soon (tonight if I'm fast). I also in passing added 
>>> the trisurf function.
>>
>>
>> Ah, ok, thanks. And absolutely *don't stress* to make that happen ;)
>>
>>   Thomas
>>
> Ok, well it was a little bit harder than I thought for a few reasons
> 
> 1) gnuplot's depth order pm3d code only works for a single surface and 
> so a set of patches that need to be depth sorted need to be plotted with 
> a single splot command
> 2) The gnuplot binary file format doesn't support "index" for splot and 
> so constraint 1) means the data has to be written as ASCII

It's been a long time since I looked at the binary mode of gnuplot, but my memory is that I implemented almost all the same features and syntax as for ASCII.  There is a binary mode for which "index" doesn't work and that is the original gnuplot matrix format.  (If the data in the file is in a matrix format, "index" makes no sense.)  However, Petr reported some gnuplot problems with binary mode just recently, and he posted a code snippet change related to a matrix flag.  You may be getting an error message when you shouldn't.


> 3) As pm3d uses the color palette, any fixed color patches need to have 
> their color added to the colormap, and then the other things plotted 
> with the colormap need to be treated carefully..
> 
> In any  case I committed the attached patch that appears to work fine 
> for all the tests I ran with the gnuplot CVS version. One issue I have 
> is with gnuplot 4.2.4 I see the attached for the command 
> "demo('patch',6); colorbar" for the X11 terminal. This appears to be a 
> gnuplot bug as it works for other terminals like png, eps, etc and it 
> works for the CVS version of gnuplot.. Should I care about this bug?

No, but if you have a moment, please post a bug report at:

http://sourceforge.net/tracker/?func=add&group_id=2055&atid=102055

and attach the figure.

Dan