The problem with dynamically switching statesets using visitors is that you
need to be able to build them on the fly. This may be doable for simple
statesets, but will very difficult/messy for complicated statesets, especially
if shaders are involved.
I've been using the switch node approach - basically inserting switch nodes and
adding the different statesets to the appropriate child. This is done as a
preprocess, configuring the models before they are loaded. I like Colins points
about node masks being more flexible for rendering multiple views and will go
back to see what it will take to try it out.
It would be nice to have a higher level stateset/shader managment capability. I
know what the response will be (develop and contribute it), which I agree
with...
Brian
> From: gor...@gordon-tomlinson.com
> To: osg-users@lists.openscenegraph.org
> Date: Fri, 13 Feb 2009 06:47:07 -0500
> Subject: Re: [osg-users] Swapping Textures for Thermal Signatures
>
> Another approach might be
>
> , If the geom is the same for both or multi spectral states, it would be
> cheaper just to swap the textures and all you need is to create 2 sets of
> osg::State sets one with your normal out the window images and the other with
> your thermal etc, then simply swap the states sets on the relevant nodes ,
> saves duplicating all the geometry. And if your textures have naming scheme
> etc then you can write a straight forward visitor to build these state sets
> for you
>
> ______________________________________________________________________________
> Gordon Tomlinson
>
> gor...@gordontomlinson.com
> IM: gordon3db...@3dscenegraph.com
> www.vis-sim.com www.gordontomlinson.com
> ______________________________________________________________________________
>
> -----Original Message-----
> From: osg-users-boun...@lists.openscenegraph.org
> [mailto:osg-users-boun...@lists.openscenegraph.org] On Behalf Of Colin Rayment
> Sent: Friday, February 13, 2009 5:12 AM
> To: osg-users@lists.openscenegraph.org
> Subject: Re: [osg-users] Swapping Textutes for Thermal Signatures
>
> We are currently doing something similar. We've considered two approaches:-
>
> One involves providing a switch node for each node/geometry that applies a
> different texture. One path applies the normal texture and the other applies
> the thermal texture, both branches then reference the same geode containing
> the geometry. By changing the status of each switch node it is then possible
> to select either the normal or thermal views.
>
> The other approach adopts a similar structure but with a group node replacing
> the switch node and each branch having a different node mask e.g. 1 for
> normal, 2 for thermal. The relevant view is then obtained by setting the
> appropriate mask settings when doing the cull traversal.
>
> Our view is that the former has the benefit of explicitly setting the viewing
> mode within the structure of the model and could be considered more
> appropriate for situations where the viewing mode doesn't change that often,
> but has issues if dynamically switching between viewing modes in that all the
> associated switch nodes will need to be changed. It also doesn't allow
> support for multiple views with differing viewing modes. The latter provides
> the benefit of a single setting changing the viewing mode and thus providing
> an easier method to switch between modes and also allows multiple views to be
> rendered simultaneously with different viewing modes. However it does require
> your viewer to explicitly set the mask settings as the default setting
> 0xffffffff would render both views simultaneously.
>
> Hope this helps
>
> Colin
>
> -----Original Message-----
> From: osg-users-boun...@lists.openscenegraph.org
> [mailto:osg-users-boun...@lists.openscenegraph.org] On Behalf Of Guy Volckaert
> Sent: 13 February 2009 00:50
> To: osg-users@lists.openscenegraph.org
> Subject: [osg-users] Swapping Textutes for Thermal Signatures
>
> Hi,
>
> I was wondering what’s the best way to simulate thermal signatures for
> targets and the terrain (i.e heat vision).
>
> One simple and easy way is to load 2 models - one for day view and another
> for thermal view. However, this poses a big problem for the terrain. I really
> don't want to load the geometry of 2 terrains since that would require too
> much memory. BTW, I use the term "model" to refer to an OpenFlight (FLT) file
> that I load.
>
> Since the geometry of both day and thermal models are identical (at least in
> my case), I should be able to load the day model and then load the textures
> of the thermal model (without loading the geometry of the thermal model).
> This can easily be done by using a filename convention such as adding the
> suffix "_tml" at the end of every thermal texture filename.
>
> This is all well in theory, but how do I implement it (I am still a rookie).
> Can anyone help me on this?
>
> BTW: I know that there are several techniques to produce good looking thermal
> signatures using shaders, but that's too fancy for me right now. I just need
> something simple that won't consume all my memory.
>
> ------------------
> Read this topic online here:
> http://osgforum.tevs.eu/viewtopic.php?p=6732#6732
>
>
>
>
>
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