Re: gEDA-user: Building the PCB+GL branch [WAS: Re: Open GL survey (for PCB)]

[Peter Clifton <pcjc2@xxxxxxxxx>]

On Wed, 2009-01-28 at 23:53 +0000, Peter Clifton wrote:

> > > Give the works so far a try:
> > > 
> > > http://repo.or.cz/w/geda-pcb/pcjc2.git
> > > 
> > > git clone git://repo.or.cz/geda-pcb/pcjc2.git
> > > git checkout before_pours origin/before_pours
> > 
> > git checkout -b before_pours origin/before_pours
> >               ^_____ Tells git to create a (local) branch
> 
> [snip]
> 
> > > (Then build as usual).
> 
> Since the latest code pushed (which has begun a slight refactoring), you
> need to call configure with "--enable-gl" for it to look for and link
> against the required OpenGL libraries and GtkGLExt.
> 
> NB: If you don't pass --enable-gl, the build fails.. I didn't yet get to
> the point where the GL code in the GTK HID is conditionally compiled in.
> At the moment, its more a GL fork of the GTK HID.


Cautionary note:

Beware of accidentally relying on a anti-polygon behaviour I was playing
with, which is still in the "before_pours" branch.

Pressing "j" over a polygon turns it into an anti-polygon, which clears
away other polygons. (It doesn't work with the electrical connectivity
check though, which may catch you out, and the whole idea might never
make it into any official PCB release!)

(The original idea was that islands might be removed as a batch
operation by inserting computed anti-polygons).


If you fancy playing with some other experimental polygon stuff though
(again, not yet backwards compatible), try the "master" branch which
does full real-time island removal. The broken pieces of "pour" are
actually now separate "polygons" internally, so work correctly for
electrical connectivity checking.

This allows (for example) one big rectangle fill to work on a board, but
allows islanded sections of the fill either to be removed, or be
re-connected (not necessarily to the same net), in order that they are
kept.

I've still not figured out how to make this work in a backwards
compatible way. It much more closely matches PCB's _old_ semantics
before Harry introduced computational polygon support. That change broke
backwards compatibility with old layouts (which assumed all pieces of 
polygon were kept) - I don't want to break anyone's designs again!


Best wishes,

-- 
Peter Clifton

Electrical Engineering Division,
Engineering Department,
University of Cambridge,
9, JJ Thomson Avenue,
Cambridge
CB3 0FA

Tel: +44 (0)7729 980173 - (No signal in the lab!)



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