[Radiance-general] Re: my real question

[Greg Ward]

Hi Qing,

I don't really have anything to add to what Dr. Peter and I have 
written, already.  You may use the -fac option of rtrace to get a 
Radiance RGBE image on the output, which you may then pass to any of 
the Radiance picture filters and converters provided (e.g., pfilt, 
pcomb, ra_ppm, etc.).  You have not given me enough specifics about 
your project for me to determine whether or not rpict could generate 
the views directly, but in most cases, it can.  Rpict has options for 
fore and aft clipping planes, parallel and fisheye views, and view 
camera features.  Anyway, if you need to use rtrace, we have given you 
at least three methods for doing so.

One other thing you might investigate is the code in 
ray/src/common/process.c, which provides routines for communicating 
with a separate rtrace process from a controlling program.  For an 
example of how you might do this, you can look at the code in 
ray/src/px/pinterp.c.

-Greg


> Hi Greg,
> Thank you for your suggestion at first!
>
> For this moment, I think I should tell you my real situation. From the 
> requirement
> of our project, I could not use the Radiance in the form of command 
> line and I
> must change some codes to form our own APIs (making use of static 
> library). Also,
> I couldn't use system calls. We can get the required image using API 
> altered from
> "rpict", and then our real problem is to specify a region (or even a 
> single pixel)
> on the image plane to get the radiance value and the picture of that 
> region. In my
> opinion, "rpict" can specify the exact position on an image plane. So, 
> I use the
> changed "rtrace" to render the region to obtain their radiance values 
> (r, g, b)
> and then I want to transform them into a suitable file form to obtain 
> the picture.
> I know I can get the answer through looking into the source codes, but 
> I do not
> have so much time for that. I have tried the method Dr. Peter told me. 
> However,
> that method sometimes works well and sometimes not. Now, I want to 
> take advantage
> the Radiance picture directly. Could you please tell me the 
> suggestion? From your
> opinion, what is the better solution for my problem?
>
> Thank you in advance!
>
> Qing