Bug 2625

Summary:	quad strips are drawn in the wrong order on tcl-capable radeons
Product:	Mesa	Reporter:	Roland Scheidegger <sroland>
Component:	Drivers/DRI/R100	Assignee:	Default DRI bug account <dri-devel>
Status:	RESOLVED INVALID	QA Contact:
Severity:	normal
Priority:	high
Version:	git
Hardware:	x86 (IA32)
OS:	Linux (All)
Whiteboard:
i915 platform:		i915 features:

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 Adam Jackson 2009-08-24 12:23:05 UTC

Mass version move, cvs -> git

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