kicad-developers team mailing list archive

[Seth Hillbrand <seth@xxxxxxxxxxxxx>]

Am 2018-12-18 07:15, schrieb jp charras:
> Le 17/12/2018 à 22:26, Seth Hillbrand a écrit :
> > Hi JP-
> > Am 2018-12-17 08:47, schrieb jp charras:
> > > Note the incorrect rendering happens only when footprints are 
> > > flipped.
> >
> > Thank you for the samples.  I had coded the tesselation assuming the
> > copper layers, which always have the polygon in CW order for the 
> > outline
> > and CCW for the holes.  But flipped footprints put the line chain in 
> > the
> > reverse order, so they render incorrectly.
> >
> > I've added some checks for the winding order to the code and 
> > re-enabled
> > the polygon caching.  Let me know if you see any issues.
>
> Thanks Seth.
>
> Could you have a look into my commit 388397f97.
> I want to be sure I did not break your code.
>
> I modified Gerbview to use your tesselation.
> During my tests, I found a crash with degenerated polygons (having less
> than 3 corners).

Hi JP-

That should not cause any issues.  But I think it is degenerate with the 
test immediately following:
if( !firstVertex || firstVertex->prev == firstVertex->next )

I've adjusted the CacheTriangulation() routine to correctly handle the 
case when tessellation fails.  Specifically, it will set 
m_triangulationValid=false if any of the polygons fail triangulation.  
This should work because DrawPolygon() falls back to the built-in OpenGL 
triangulation if the triangulation is not cached.  The exception is in 
the 3dviewer, which does not draw polygons.  For this reason, we still 
attempt the remaining triangulation even after we set the failure flag.

Let me know if you see any issues.

Best-
Seth