Subsurface?

Has anyone done any work on what it would take in Paging Scene manager to put a cave into a mountain that lead to a BSP level or similar type of level ?

I have been doing some thinking on this. Would it be possible to put a polygon where you wanted a cave entrance and then render the inside of the cave as a renedered texture, then shift the player into the cave once the cave was at the near culling point ?

I guess the question that follows is if you can have another scene manager besides the one you are using do the render to texture?

Kiolakin, hi

I´m quite new to Ogre and PLSM2 in particular. AFAIK PLSM2 does exactly
what its name says; it renders landscape.

Unlike room-based engines (like Quake or Tomb Raider, which I know best)
in PLSM2 there are no Portals or rooms in a classical way.

I´m sure that w/ some modifications... err.. a lot of modifications ... OGRE
would be able to do such things but it´s not an easy task. That´s not only
for us OGRE people, lots of "commercial" Game companies fear the effort.

Take Beth Soft´s Morrowind, for example; even their Next Gen RPG Oblivion
does reloading when the cam changes from exteriour to intriour cells.

only thing I can propose would be a way not to load a Tile or a Page and you just put there the cave instead.
Tricky, as you should make a LODed version of the borders to suits lod stitching (check wireframe mode to understand how stitching works.)

Otherwise you should go for a portal multi-scene manager system.

Looks like someone in the addons group has been working on a multiscene manager which is basically a portal implementation for ogre. Has anyone checked this out with PLSM ? It seems that PLSM would be greatly benifited by this. If anyone has any information on this please post, I haven't run through the wiki yet, but looking at the project there seems to be a great bit missing including any documentation.

there's a "multiscenemanager" folder in ogreadons cvs folder.
btw plsm2 documentation IS the Wiki.

My apologies, I meant no documentation for multiscenemanager.

I'd suggest using as many tricks as possible if you wanted to get it down without major work.

For example, are you willing to have the character walk into an area and then pause while a new area loads?

In that case you could do what Guild Wars and Morrowind do and create an outcropping of cave entrance which is in fact a mesh that juts out from the mountain. When the user walks into the cave entrance you load a new area.

The new area could be completely mesh based for the cave interior, as Morrowind does, or better yet, you could use the terrain system for the ground and have a mesh ceiling that slopes down to meet the ground, like Guild Wars does. It works very well in Guild Wars' underground areas.

Another possibility depends on how deep your caves need to be. For example, if you just need small caves you could place a mesh over the terrain for hill top and cave roof and have the terrain continue as the ground of the cave and come out the other end, as the snowboarding game SSX does for it's small caves that the user snowboards through.

I've given some thought to this since I'd like to do caves in my game and I'm going to go with the Guild Wars method

hmmm its scary that everyone thinks that implementing portals would be that difficult. Why is it more difficult than having a mesh entrance but on the polygon that covers the entrance RTT the inside of the cave? When the user crosses a certain line you could actually place them inside the cave that you have designed. The same could be done for the exit...


I worked with Crystal Space so long before I came to Ogre it is difficult for me to think in terms of anything other than portals. Its too bad Ogre has PLSM but crystal space has everything else...

From my investigation into CystalSpace, it is built around using CSG map editing tools such as Quark, Q3Radiant, Hammer, and perhaps a few others such as a Blender to cs map tool, and then converting from the .map format to a custom cs format. It is restrictive in the fact that you must use those tools, and have to build your game around portal based rendering. How about a flight sim? An outdoor expansive game? CS uses portals, but an engine built entirely around portals is no longer a good thing with todays 3d cards because of geometry batching and such. Modern engines such as the Unreal 3 engine, Half Life 2 / Source engine, etc. are using portals less and less, even though they're technically supported by the engines. Unreal uses a lot of hardware occlusion queries and meshes instead of CSG maps. The source engine uses the CSG maps for just the basic layout, and the rest is placed meshes.

Implementing portals is the rendering engine is pretty difficult, but not impossible. It would just take someone with a lot of free time on their hands to implement. There are a lot of caveats though - because of all the things that come up when you deal with portals. Lights through portals, shadows, collision detection, etc. Complex portals that recurse back onto themselves. Things that have to exist in two cells at the same time, etc. add up to a lot of technical issues.

Sinbad is coming up with a new automatic portal generator that can generate portals from polygon soup, and a renderer that knows how to use the output of the generator to cull the scene properly, however I don't believe even this is a full portal implementation where you can be looking through a doorway into a completely different part of the world.

For whoever suggested using a render to texture, the only obvious problem with that is the resolution. I'd like to see it though because that's a pretty cool idea.