Bug 2625 - quad strips are drawn in the wrong order on tcl-capable radeons
Summary: quad strips are drawn in the wrong order on tcl-capable radeons
Alias: None
Product: Mesa
Classification: Unclassified
Component: Drivers/DRI/R100 (show other bugs)
Version: git
Hardware: x86 (IA32) Linux (All)
: high normal
Assignee: Default DRI bug account
QA Contact:
Depends on:
Reported: 2005-02-27 16:21 UTC by Roland Scheidegger
Modified: 2009-08-24 12:23 UTC (History)
0 users

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Description Roland Scheidegger 2005-02-27 16:21:32 UTC
With tcl_mode!=0, Mesa/samples/prim exhibits a bug with quad strips (at the top
right), the colors are switched compared to indirect rendering / sw tcl. AFAIK
this is due to the quad strips (reduced to another primitive since the radeons
don't support quads nor quad strips) being drawn in the wrong order. This is
probably a bug somewhere in the tnl code, IIRC the r200 had the same bug before
it was switched to use the native hw quads.
Comment 1 Roland Scheidegger 2005-03-01 06:18:53 UTC
Turns out this probably isn't a bug. The interpolation for smooth shading is
different with hw quad strips and tri strips (which is what is used if hw quad
strips are not available). If I interpret the gl spec correctly, they actually
both seem to be correct (color interpolation with polygons which consist of more
than 3 vertices is surprisingly vague).
Comment 2 ajax at nwnk dot net 2009-08-24 12:23:05 UTC
Mass version move, cvs -> git

bug/show.html.tmpl processed on Jun 26, 2016 at 15:21:16.
(provided by the Example extension).