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[elFer]

Hi, I want to create an interface 3d to visualize gis Data. In the first state of the project, I want to place images (satellite images) into a flat surface dinamicaly. I download the textures from a Geoserver service (via http), and I want to load this textures (256*256pixels) to visualize over the flat terrain. When the user move the camera, the program must unload/load this textures (the images download from the server are save on hh.dd, in order to download only one time).
But, where I apply this textures???. Can I create an 2d object (plane) and put over this all the textures dinamicaly?, or I have to create many 3d quad object (a box without thickness) and apply the textures over single objects?.

Thanks in advanced...
..and apologize for my english....

['n ddrylliog]

Hi elFer, welcome to Xith3D !

I guess the best would be to have several quads : it's more fexible, you can also do culling like that. Multi-texturing a single plane would be also possible but more difficult, and some cards only have 2-4 texture units so you would have to create a HUGE texture and *paint* the images you downloaded from the http servers directly on it : that would be really slow. So I advise you the first solution : several quads.

[Marvin Fröhlich]

I agree. Several Quads is certainly the simplest and the fastest solution (of the simple ones).

Creating a huge Texture would not even work because of maximum Texture size of OpenGL.

Marvin

[Mathias 'cylab' Henze]

Maybe you are interested in the current terrain development. Texture LOD is the next thing on my todo-list...

[elFer]

I made some test with the terrain clases (1year ago). But the terrain that I have it's too large, 300km*150km with 10m*10m of DEM resolution (we need to download terrain data in real-time too). I start my project without DEM representation, but in future I would like to view the terrain. The first steep is see a plain map with textures that load (and unload) dinamicaly.

Thanks....

[Mathias 'cylab' Henze]

the new implementation (has nothing to do with the old one) will support this requirement. If you are interested to help out, maybe we could both benefit.

[Marvin Fröhlich]

What is DEM (except for the short form for D-Mark )?

Marvin

PS: It's dynamically not dinamically

[Mathias 'cylab' Henze]

digital elevation model

[elFer]

DEM is Digital Elevation Model. It's a bitmap where every pixel represent the height of the terrain in this point. I access to the DEM through http: I request to the server with two corner coordinates, and the server response is a gif where the height is codified as a color (I use WMS server).
Can I dinamicaly change the LOD of terrain with Xith?. I start using plane quads for texturing, but the next step is apply the DEM to this quads. But the problem is the 'streaming' of the textures and bitmaps of terrain model. As the user move the camera, textures and terrain will load/unload from memory....
Thanks...

[Mathias 'cylab' Henze]

Can I dinamicaly change the LOD of terrain with Xith?. I start using plane quads for texturing, but the next step is apply the DEM to this quads. But the problem is the 'streaming' of the textures and bitmaps of terrain model. As the user move the camera, textures and terrain will load/unload from memory....

The terrain implementation is not finished (here is an overview of planned features), but the plan is to provide multiple detail levels for height data and textures. It's basically an implementation of the Chunked LOD algorithm by Thatcher Ulrich (linked in the overview) with the triangulation borrowed from SOAR. Maybe helping out in the terrain implementation will result in exact the application you are trying to create.