debugging WAS: [PD-dev] Inconsistency in behaviour using Gem... my fault?
hans at eds.org
Wed Nov 1 17:29:00 CET 2006
First off, its helpful to split off multiple questions into multiple
emails. Most people don't expect a new topic at the bottom of a long
email. If you write really long ones like this, then you're
questions will most likely be overlooked. I skimmed to the bottom
and saw the stuff about debugging.
Debugging is an area that could use some work. I know that Max/MSP
has a stepper but I have heard from some that its useless, while
others say they sometimes find it useful. Right now, the [print] is
the main debug mechanism. But you can make print much easier to
use. That's basically the most used functionality of gdb: live,
interactive printf() of variables.
Here's a super quick demo:
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On Nov 1, 2006, at 4:23 AM, Nick Bailey wrote:
> Hi pd community. I have a suspected bug but before I raise it with
> the Mac developers, I thought I'd ask some experts to make sure it
> isn't my fault.
> Using pd 0.39-2 on Linux (Debian Sid) to do my development, but
> wanting to deploy on my Mac Powerbook using "Pd-extended" 0.39-2
> beta4 from http://at.or.at/hans/pd/installers.html on the Mac
> (there's a 5th beta release on that site, but it won't even start
> for me).
> Problem involves a Gem patch. We want to divide a photograph up
> into tiles, so each can individually cross-fade between one photo
> and the next. I made a first rough cut of a UI to do this called
> imageMixer.pd on my Linux box (it's at http://
> markov.music.gla.ac.uk/boston.tar.bz2 - 465K). After playing with
> it for a while, I attemted to transfer it to my PowerBook, and it
> sort of worked, but when rendering was switched on, I got a
> continuous message:
> separator : state->numTexCoords 4 != m_state.numTexCoords 0
> repeated over and over again. The separator in question turns out
> to be in [pd tile] which is in [pd tile_array] (at the bottom right
> of the patch).
> Playing around a bit more, I came up with imageMixer-mac39.pd. This
> gets rid of the separator in [pd tile] and just has a gemhead
> feeding both pix_image. This works fine on the Mac (though I was
> led to believe you had to use a [separator] here... why not? Should
> it not work?) but on the linux box it doesn't fade between two
> different images, it fades between image and black.
> The final attempt (imageMixer-2.1.pd) simply moves the gemhead
> outside of [pd tile] and back into [pd tile_array]; this works on
> both machines.
> Now, this is my first ever pd patch (except for a very simple one I
> wrote to demonstrate writing an LPC pd plugin to my students), and
> certainly my first outing with Gem, so it's very likely I've just
> missed the plot with the semantics of gemheads, separators etc. It
> does look to me like there might be a bug in separator on Pd-
> extended for the Mac though. It is after all a test release.
> Consequently any comments directed to me regarding RPI (removal of
> pig-ignorance) or style criticisms would be very well received. If
> people think it's a bug, I'll file a report with the Mac packager
> (or maybe s/he's already reading this?)
> One last question. pd/Gem was certainly a rapid development tool
> for the concert which is going to be in Boston MA in a few days'
> time, but apart from the judicial use of [print] and numbers,
> staring at the code, and bleating for help from my postgraduates,
> are there any better ways of debugging patches? You'll have guessed
> from my email address that I'm from a different programming
> background, and use gdb and the like much more frequently. I've
> certainly learned to be very strict about versioning. Messing
> around for an hour or so with a patch, then not being able to use
> diff to see what one's ended up changing makes one take particular
> care in that direction!
> Thanks in advance for your helpful advice and comments,
> PD-dev mailing list
> PD-dev at iem.at
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