[Radiance-general] Re: falsecolor and textlabels question

[Greg Ward]

Rpict doesn't "remember" the setting from a previous run, if that's 
what you're thinking.  It only remembers it from previous appearances 
of the option.  For example:

% rpict -i

turns irradiance computation on, but

% rpict -i -i

turns it off again.

% rpict -i -i -i -i -i -i+

turns it  on.  (Had you counting, didn't I?)  If your intention is to 
switch the option "on", then -i+ (or equivalently, -iY -iy -iT -it -i1 
all mean the same) is probably better.

The reason rpict pays attention to multiple appearances of an option is 
in case you have aliased your version of rpict to something else, e.g. 
the following in your .cshrc file:

alias robpict 'rpict -ab 1 -ad 2048 -i+ \!*'

Then, every time you ran "robpict" instead of "rpict," you would get 
the set of starting options above.  If you ran "robpict -defaults", 
you'd get to see these options and how they affect the normal default 
values.

In other words, giving an option then overriding it later on the 
command line makes sense in terms of creating your own default sets, 
which you can incorporate into an alias as above or put into an options 
file and read with the @file.opt feature.  Using rad, the render= 
variable overrides whatever parameters rad has set for you.

Does this make sense?
-Greg

> From: Rob Guglielmetti <rpg at rumblestrip.org>
> Date: March 17, 2004 11:09:54 AM PST
>
> Greg Ward wrote:
>
>> % rpict [same options] -i+ octree > illum.pic
>
> You know, all this time, I've always used "-i" to compute irradiance, 
> thinking it was functionally equivalent to "-i+".  If the default is 
> for rpict to compute radiance, I'd expect "-i" to always cause an 
> irradiance calculation, the same as "-i+", and that's been my 
> experience.  In re-re-re-reading the manpage, I see:
>
> "Normally, the appearance of a boolean option causes a feature to be 
> 'toggled', that is switched from off to on or on to off depending on 
> its previous state."
>
> How does rpict "remember" what state it was placed into from one 
> instance to the next?  I suppose the safe thing to do is to always 
> call the option explicitly, but I'm curious now: can someone give me 
> an example of rpict "remembering" it was set to compute irradiance?
>
> ----
>
>      Rob Guglielmetti