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PostPosted: Fri Mar 28, 2008 6:37 pm
by JohnJ
Huge, efficiently rendered, fully detailed, dynamically shaded planets with real-time planetary gravity simulation:
Image Image

Engine technology is an expansion of the Ogre graphics engine.

Just thought I'd post these nice looking "terrains" here in case anyone's interested. Planets are basically "spherized" cubes, where each cube face can have it's own heightmap / textures / etc. This works really well because it's still just a heightmap based system, just that there are 6 heightmaps for each planet.

Unfortunately L3DT doesn't adapt well to planetary terrain generation (due to seams at the corners of the "cube" layout, so I may have to make my own terrain generator if I can't work out the problems with L3DT :(.

PostPosted: Mon Mar 31, 2008 3:19 pm
by Peter
Looks good, I'm a big fan of Ogre, very efficient rendering. Any chance you could post a wireframe screenshot of your planets?

PostPosted: Mon Mar 31, 2008 4:09 pm
by JohnJ
Here's an (old) screenshot showing how the LOD system works:

And here's a really old video with wireframe demonstrating the LOD system:
WMV Video (5.5 mb)

PostPosted: Mon Mar 31, 2008 5:08 pm
by Peter
Ah cool, that's really neat =] good work.

Re: Planets!

PostPosted: Tue Apr 01, 2008 10:21 am
by Aaron
Hi JohnJ,

Awesome work, as always. I think we're all still a little giddy after your foray into fast foliage rendering, but I'm glad to see you're keeping yourself busy with interesting new projects.

JohnJ wrote:Unfortunately L3DT doesn't adapt well to planetary terrain generation (due to seams at the corners of the "cube" layout, so I may have to make my own terrain generator if I can't work out the problems with L3DT :(.

Hmm...I've had a thinker about this in the past. I've pretty-much discounted the possibility of generating the whole terrain as a spherical mesh, since I'd basically have to start from scratch. My erosion and other mapping routines would not translate to non-Cartesian grids without, effectively, a total re-write. As much as I relish a challenge, this would have to be a very long way down on the priority list (much other cool stuff planned for the next few releases.)

The other alternative was to generate the terrain as a regular heightmap, and then apply all the requisite distortions to stitch the map into the 6 or more heightmaps. Tillot and I made a sort of quick-n-nasty spherical distortion plugin, but this only worked on the heightmap cube facets individually, and didn't attempt to merge the seams. However, I'm quite sure a better plugin could be written to do smooth spherical distortion with facet stitching, given an arbitrarily clever programmer with suitable motivation and time.

Of course, it then becomes an issue to generate attributes/land type maps for the distorted heightmaps, as L3DT's attributes map algorithms won't work on tilted terrain without modification. Without looking at the code in detail I can't say whether it could be suitably modified without a rewrite either.

Anyway, I'm very interested to see where you go with this. Please keep us posted.

Best regards,

PostPosted: Tue Apr 01, 2008 3:34 pm
by JohnJ
Yeah, this is really just a progression of where I was going before - huge, vast worlds with lots of detail. I plan to integrate my tree / grass engine into my planet system as well. This technology will be going into an actual game too, so it's not just a prototype either.

Regarding terrain generation: Actually, the system works quite well with standard flat heightmaps - they're mapped onto a sphere using a special formula that eliminates distortion around the seams. The only problem is that the edges need to be "stitched" or made seamless, which I hope won't be a problem - just that I haven't gotten to that yet.

PostPosted: Wed Apr 02, 2008 1:31 pm
by monks
Very exciting stuff JohnJ, and the foliage was exceptional. :)

Been planning...and meaning to get back to looking into the whole rt engine situation for ME-DEM Project, amd post on the Ogre boards some terrain screenies. This looks just the ticket.
It'd be great so see a more developed workflow between modeller and (planetary) renderer. Aaron has been instrumental in forging a direct path between Global Mapper (GIS) and L3DT (terrain modelling) via the hf2/z file format. That format's going to be adopted/ implemented shortly by another well known terrain app. Others will follow! :)
With hf2 having the option of including projection/georeferencing info, the whole projected terrains thing is at least one step closer.