DrawDots issue

1
Hi all,

A quick question: I am trying to set up a remote collaborator with a PTB script I wrote. The
basic issue is that all drawdots calls with shape parameters 1 or 2 are squares, not dots.
This is true in my script, but also in DotDemo (except for the middle dot, which seems to
be made by 'FillOval'). Adding

Screen('BlendFunction', w, GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

doesn't help.

She is using an intel MacBook with OS 10.5.4 and Matlab 7.6, plus PTB 3.0.8; the graphics
card on the laptop is an Intel GMA X3100. It looks like this graphics card supports a dot
size range from 1:64, based on

glGetIntegerv(GL.SMOOTH_POINT_SIZE_RANGE)

but dots at a range of sizes don't work.

Any thoughts would be much appreciated! I can work around via FillOval calls, but in
general it'd be nice to figure out what's going on. Thanks in advance,

tD: Mike.
2
Hi all,

A quick question: I am trying to set up a remote collaborator with a PTB script I wrote. The
basic issue is that all drawdots calls with shape parameters 1 or 2 are squares, not dots.
This is true in my script, but also in DotDemo (except for the middle dot, which seems to
be made by 'FillOval'). Adding

Screen('BlendFunction', w, GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

doesn't help.

She is using an intel MacBook with OS 10.5.4 and Matlab 7.6, plus PTB 3.0.8; the graphics
card on the laptop is an Intel GMA X3100. It looks like this graphics card supports a dot
size range from 1:64, based on

glGetIntegerv(GL.SMOOTH_POINT_SIZE_RANGE)

but dots at a range of sizes don't work.

Any thoughts would be much appreciated! I can work around via FillOval calls, but in
general it'd be nice to figure out what's going on. Thanks in advance,

tD: Mike.
3
Maybe your graphics chip does not support hardware anti-aliasing?
see http://homepage.mac.com/arekkusu/bugs/invariance/
We experienced the same problem with older Radeons, e.g. 7500, and it
is independent of psychtoolbox;

Regards, Jochen

On Sep 10, 2008, at 20:38, mcxfrank wrote:

> Hi all,
>
> A quick question: I am trying to set up a remote collaborator with a
> PTB script I wrote. The
> basic issue is that all drawdots calls with shape parameters 1 or 2
> are squares, not dots.
> This is true in my script, but also in DotDemo (except for the
> middle dot, which seems to
> be made by 'FillOval'). Adding
>
> Screen('BlendFunction', w, GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
>
> doesn't help.
>
> She is using an intel MacBook with OS 10.5.4 and Matlab 7.6, plus
> PTB 3.0.8; the graphics
> card on the laptop is an Intel GMA X3100. It looks like this
> graphics card supports a dot
> size range from 1:64, based on
>
> glGetIntegerv(GL.SMOOTH_POINT_SIZE_RANGE)
>
> but dots at a range of sizes don't work.
>
> Any thoughts would be much appreciated! I can work around via
> FillOval calls, but in
> general it'd be nice to figure out what's going on. Thanks in advance,
>
> tD: Mike.
>
>
> ------------------------------------
>
> Post your message to: psychtoolbox@yahoogroups.com
> Please indicate OS9, OSX, or WIN version, and include your full name.
> Denis Pelli, David Brainard, and Allen Ingling.
> http://psychtoolbox.org
> Yahoo! Groups Links
>
>
>
4
Nope. Maybe upgrade to OS/X 10.5.5 to see if it
has been fixed there. If not, one could file a
bugreport.

Other than that 'FillOval' is your best choice.
You'd use only one 'FillOval' statement though,
but submit all dots at once in a matrix, just as
you'd do with 'DrawDots'.

See 'DrawingSpeedTest.m' for demo and benchmark
on batch-drawing mode.

-mario

--- In psychtoolbox@yahoogroups.com, Michael C Frank <mcfrank@...> wrote:
>
> All dot sizes fail, strangely enough. It does sound like a driver bug.
> Do you have any thoughts for a workaround aside from lots of FillOval
> statements?
>
> best,
>
> tD: Mike.
>
> On Sep 11, 2008, at 1:34 PM, Mario Kleiner wrote:
>
> > Certainly a graphics driver bug. Either because it doesn't
> > work in the reported range 1-64, or because it reports
> > a wrong working range.
> >
> > Do all dot sizes fail, or only big ones?
> > -mario
> >
> > --- In psychtoolbox@yahoogroups.com, "mcxfrank" <mcxfrank@> wrote:
> > >
> > > Hi all,
> > >
> > > A quick question: I am trying to set up a remote collaborator with
> > a PTB script I wrote.
> > The
> > > basic issue is that all drawdots calls with shape parameters 1 or
> > 2 are squares, not dots.
> > > This is true in my script, but also in DotDemo (except for the
> > middle dot, which seems
> > to
> > > be made by 'FillOval'). Adding
> > >
> > > Screen('BlendFunction', w, GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
> > >
> > > doesn't help.
> > >
> > > She is using an intel MacBook with OS 10.5.4 and Matlab 7.6, plus
> > PTB 3.0.8; the
> > graphics
> > > card on the laptop is an Intel GMA X3100. It looks like this
> > graphics card supports a dot
> > > size range from 1:64, based on
> > >
> > > glGetIntegerv(GL.SMOOTH_POINT_SIZE_RANGE)
> > >
> > > but dots at a range of sizes don't work.
> > >
> > > Any thoughts would be much appreciated! I can work around via
> > FillOval calls, but in
> > > general it'd be nice to figure out what's going on. Thanks in
> > advance,
> > >
> > > tD: Mike.
> > >
> >
> >
> >
>