Bug 60797

Summary:	1px lines in octave plot aliased to 0
Product:	Mesa	Reporter:	Cedric Sodhi <manday>
Component:	Drivers/DRI/i965	Assignee:	marius predut <marius.predut>
Status:	RESOLVED DUPLICATE	QA Contact:
Severity:	normal
Priority:	medium	CC:	siglesias
Version:	9.0
Hardware:	Other
OS:	All
Whiteboard:
i915 platform:		i915 features:
Attachments:	apitrace output

Description Cedric Sodhi 2013-02-13 15:13:40 UTC

With Octave 3.6.3

OpenGL renderer string: Mesa DRI Intel(R) Sandybridge Mobile
OpenGL version string: 3.0 Mesa 9.0.1
x11-drivers/xf86-video-intel-2.21.2
8086:0106 (rev 09) 

gt1

also on

gm45

Start octave, perform as shown here [1]:

graphics_toolkit( "fltk" )
tx = ty = linspace (-8, 8, 41)';
[xx, yy] = meshgrid (tx, ty);
r = sqrt (xx .^ 2 + yy .^ 2) + eps;
tz = sin (r) ./ r;
mesh (tx, ty, tz);

The resulting plot doesn't look like in [1] but instead the thin gridlines vanish due to aliasing. LIBGL_ALWAYS_SOFTWARE=1 does not show such behaviour.

[1] http://www.gnu.org/software/octave/doc/interpreter/Three_002dDimensional-Plots.html#Three_002dDimensional-Plots

Comment 1 Samuel Iglesias Gonsálvez 2014-03-12 13:27:17 UTC

Created attachment 95661 [details]
apitrace output

Comment 2 Samuel Iglesias Gonsálvez 2014-03-12 13:33:42 UTC

I can reproduce this bug with Octave 3.8.0 and latest version of mesa:

OpenGL vendor string: Intel Open Source Technology Center
OpenGL renderer string: Mesa DRI Intel(R) Sandybridge Mobile 
OpenGL core profile version string: 3.1 (Core Profile) Mesa 10.2.0-devel (git-952fda4)
OpenGL core profile shading language version string: 1.40
OpenGL core profile context flags: (none)


As Cedric says, if LIBGL_ALWAYS_SOFTWARE=1 is exported then the plot is rendered fine.

Comment 3 Samuel Iglesias Gonsálvez 2014-03-17 09:59:08 UTC

It is a duplicate of bug 28832 but, at this case, octave is showing the AA line width bug.

*** This bug has been marked as a duplicate of bug 28832 ***

Comment 4 marius predut 2015-05-06 19:05:45 UTC

The patches that fix this bug is up-streamed

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