Hi,
you could look at osgSim::OverlayNode for a start.
jp
James Adkison ARA/CFD wrote:
Jason,
I’m going to try the ‘project textures onto the terrain via UV mapping’
solution today. I searching how to do this right now and I’m not sure
if I finding relevant information. Can you provide a brief/high-level
description of the steps I would need to go through to perform the UV
mapping, specifically what classes and/or API calls would be involved,
or a tutorial? I found some information on a RTT camera but I’m not
sure if this is what I’m looking for.
James
*From:* [email protected]
[mailto:[email protected]] *On Behalf Of *Jason
Jerald
*Sent:* Wednesday, October 21, 2009 9:09 PM
*To:* 'OpenSceneGraph Users'
*Subject:* Re: [osg-users] z-fighting issue with coplanar polygons
I don’t see much for performance implications as long as you are not
dynamically changing the texture every frame.
Jason
*From:* [email protected]
[mailto:[email protected]] *On Behalf Of *James
Adkison ARA/CFD
*Sent:* Wednesday, October 21, 2009 11:56 AM
*To:* OpenSceneGraph Users
*Subject:* Re: [osg-users] z-fighting issue with coplanar polygons
I’m not very experienced in OSG and I spoke to a co-worker about this
approach. The thought is that there might be some performance
implications with this approach. This is because there may be multiple
surface feature types and they can be enabled/disabled separately. For
example, if there are lakes and forests they will be created in the
texture but each time one of them is enabled disabled this process has
to be repeated and each texture would be approx 1k x 1k. I’m going to
give it a shot and see how it performs. Any other thoughts in the mean
time?
James
*From:* [email protected]
[mailto:[email protected]] *On Behalf Of *Jason
Jerald
*Sent:* Wednesday, October 21, 2009 2:16 PM
*To:* 'OpenSceneGraph Users'
*Subject:* Re: [osg-users] z-fighting issue with coplanar polygons
Can you project onto a texture and then apply the texture to the
geometry? Either in a modeling package or algorithmically by rendering
to a texture and then project that texture onto the terrain by planar uv
mapping?
Jason
*From:* [email protected]
[mailto:[email protected]] *On Behalf Of *James
Adkison ARA/CFD
*Sent:* Wednesday, October 21, 2009 10:25 AM
*To:* [email protected]
*Subject:* [osg-users] z-fighting issue with coplanar polygons
I’m using an Heightfield to represent my terrain and parts of the
terrain could have a surface feature (e.g. a lake). The lake is being
drawn as a polygon directly on the surface of the terrain. This, of
course, is causing z-fighting to occur between the terrain and the
surface feature. I have been trying to solve this problem and have run
across a couple solutions but they aren’t working for me.
I have tried using polygon offset with the GL_OFFSET_POLYGON_FILL mode,
which works when zoomed out far but up close z-fighting still occurs.
I have tried using a stencil buffer approach but I can’t get it to work
properly. I can get the surface feature to stencil out the area of
terrain but if you rotate the scene so that the surface feature is
behind a mountain the stencil is still in place and the feature is
rendered through the mountain. Hopefully, I am doing something wrong
and someone can explain how I can make this work.
James
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