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- Path: sparky!uunet!olivea!sgigate!odin!sgihub!zola!jellotrees!joel
- From: joel@jellotrees.esd.sgi.com (Joel Tesler)
- Newsgroups: comp.sys.sgi.graphics
- Subject: Re: using Overlay planes with the GlxMDraw Widget
- Message-ID: <vathtok@zola.esd.sgi.com>
- Date: 25 Jan 93 17:40:11 GMT
- References: <C1By8u.JFv@news2.cis.umn.edu>
- Sender: news@zola.esd.sgi.com (Net News)
- Organization: Silicon Graphics, Inc. Mountain View, CA
- Lines: 26
-
-
- In article <C1By8u.JFv@news2.cis.umn.edu>, moses@i5.arc.umn.edu writes:
- > I am using the GL Widget in combination with motif. I want to use the
- > overlay plane for rubber-banding.
-
- A couple of things:
-
- First, are you installing the colormaps? You need to use
- XSetWMColormapWindows to install the colormaps of both the normal and
- overlay GL colormaps. If they aren't installed, you won't get the
- correct colors.
-
- Second, and this is probably the problem, you are trying to use RGB
- for the overlay planes. Some of our very high end hardware may
- support this (I don't know for sure), but most of the hardware
- doesn't; and none of it does with overlays with a depth of 2. With a
- depth of 2 you have exactly 3 colors + transparent; and the best way
- to allocate those three colors is to use X color allocation
- mechanisms (It is often a good idea to get a new X colormap for the
- overlay planes so you don't need to share the 3 colors between
- multiple applications). Then use color (not c3i) to allocate the colors.
-
-
- Joel Tesler
- joel@sgi.com
- 415-390-3048
-