From: Benedikt Kessler (bjk++at++munich.sgi.com)
Date: 07/10/2000 06:09:41
Hi!
Antialiased lines will probably not fix the problem; the Octane has no
multisampling capabilities and therefor you need alphablending to draw
your antialiased lines. You may get the colors of the lines mixed when
using antialiased lines (do you want this to happen?). But as your lines
are partly be overlapping, I think you may get similar problems as
before (due to different depth values of the overlapped lines when they
do not start and end at the same coordinates).
Take a look at the glPolygonOffset manpage. A small offset to your lines
(different offsets for different colors) may help the lines from mixing
up.
Bye! Benedikt
Brian Furtaw wrote:
>
> You are seeing the the results of rendering on a machine with
> anti-aliasing (the IR) and rendering on a machine without(the Octane).
> The Octane does have the ability to render anti-aliased lines. I can't
> find any direct support for line smooth in Performer although some one
> else might. To enable this feature in OpenGL use
> glEnable(GL_LINE_SMOOTH), read the glLineWidth man page for details
> about anti-aliased lines on the Octane. You could enable and disable
> line smooth in a pre and post draw callback. You can use glGetString
> GL_RENDERER to identify when you are running on the Octane and install
> callback.
>
> I don't know if you have enabled blending or not. As an experiment set
> the pfTransparency() to PFTR_HIGH_QUALITY this may enable the linesmooth
> on the Octane. This will also slow things down so use it only when you
> need it.
>
> Brian
>
> christopher.g.dorosky++at++lmco.com wrote:
> >
> > Hello,
> >
> > I have an application that draws thin lines (about 5 pixels wide or so),
> > around areas of interest. These lines can be different colors. In one
> > instance, there can be yellow and red lines which overlap in places. The
> > problem is, I am seeing different results on different machines.
> >
> > On an Onyx2 IR2: Overlapping yellow and red lines blend to create an orange
> > segment in the overlap region.
> > On an Octane: Overlapping yellow and red lines flash back and forth
> > depending on how I look at them. Sometimes, they even stripe between yellow
> > and red.
> >
> > The octane effect is annoying. Does anybody know how I can either assert
> > one color as dominant, or allow them to blend like the Onyx2 does? The lines
> > are created with pfGeosets.
> >
> > Thanks!
-- +---------------------------------+----------------------------------+ |Benedikt J. Kessler | Silicon Graphics GmbH | |Professional Services | Am Hochacker 3 - Technopark | |SGI | 85630 Grasbrunn-Neukeferloh, FRG | | --- __o ,__o | | | ------_ \<,_ _-\_<, | Phone: (+49) 89 46108-366 or -0 | |----- (*)/ (*) (*)/'(*) | Fax: (+49) 89 46107-366 | +---------------------------------+----------------------------------+ |E-Mail: bjk++at++sgi.com Web (private): http://reality.sgi.com/bjk | | Web: http://www.sgi.de/dienstleistungen/ | +--------------------------------------------------------------------+
This archive was generated by hypermail 2b29 : Mon Jul 10 2000 - 06:09:54 PDT