2 rendering changes I'd love to see in Xonotic

2 rendering changes I'd love to see in Xonotic - Printable Version

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2 rendering changes I'd love to see in Xonotic - MirceaKitsune - 08-25-2012

So there's this open-source project I'm interested in called GRIT. It's planned to be an engine for games like GTA (you play as various characters, drive cars, etc) and uses OGRE for rendering. A few days ago there were some updates to materials and the lighting system, so I updated SVN and checked them out. I saw some highly impressive graphics which I haven't seen in any open-source engine so far, but have in most modern games (3 years or more recent). I decided to make a comparison with it, about two render features I'd love to see in Xonotic and wish to know if they are possible.

The biggest feature that impressed me is how GRIT handles lighting on normal mapped surfaces. Light is culled by the texture's norm-map to a very visible extent, whereas in Xonotic this is only noticeable if you look very close at some surfaces (regardless of the angle of the light). What Xonotic might need is a cvar to adjust how much the deform of normal maps culls angled lighting, but this should also affect lightmaps.

IMO that looks amazing, do want! I already looked for a cvar, but the only one I know of is a setting to adjust the intensity of parallax maps, not how they affect light.

Second effect I noticed in GRIT (and a lot of nice games) is metallic cubemap reflections. Xonotic has an issue here: It does support cubemaps (as well as the _reflect texture to mask them) but not a way to adjust their deformation so they give that bent metal feel. Yes, the normal map deform of a surface does affect cubemap reflections as well, but such cubemaps also need a separate deformation. In those engines, rotating the camera causes cubemaps to deform to a very large extent, giving the feeling that the surface is crushed / undulated metal, although the norm-map only deforms a few details on the surface (and does not necessarily contribute to that). In my opinion, Xonotic needs a way to optionally deform cubemaps using a different texture. Or maybe it can be done with the texture's normal map, but it needs to be much more visible.

That's a screenshot from GRIT of the cubemap testing. If you look close at the leftmost two spheres, you can see the reflection gives an oil like feeling, because it's deformed despite the round surface. The second ball also uses a better blending technique... while in Xonotic they're usually additive which is rather unrealistic (might change that myself if possible). Also note that I already created cubemap reflections for the exX set, but the branch is awaiting merge for many months (as usual lol).

So... any way to achieve such graphics in Xonotic? That lighting at least would be killer, but I also keep my aim to cubemap all metal surfaces to look similar to the balls in that screenshot. Where would an engine change be needed, and would the lights on maps need to be changed as well?

RE: 2 rendering changes I'd love to see in Xonotic - rocknroll237 - 08-25-2012

Wow, checking out that engine now... Looks great! Big Grin

(Talk to div or someone about this, I have no idea whether it can work or not..)

RE: 2 rendering changes I'd love to see in Xonotic - MirceaKitsune - 08-25-2012

(08-25-2012, 07:33 AM)rocknroll237 Wrote: Wow, checking out that engine now... Looks great!

(Talk to div or someone about this, I have no idea whether it can work or not..)

Yes, it's a really awesome engine. If you're interested in it, feel free to join #gritengine on the gtanet IRC server, and see http://gritengine.com/ too. But yeah, I'd love to see features like this for us as well.

RE: 2 rendering changes I'd love to see in Xonotic - Mr. Bougo - 08-25-2012

Please stop using pics.nn, it's down right now and I can't see the shots :X

RE: 2 rendering changes I'd love to see in Xonotic - hutty - 08-30-2012

hmm ... looks interesting ...

however ... I would also like to see working refraction without reflection (cause all I get is a flickering mess)

RE: 2 rendering changes I'd love to see in Xonotic - MirceaKitsune - 08-30-2012

(08-30-2012, 04:16 PM)hutty Wrote: hmm ... looks interesting ...

however ... I would also like to see working refraction without reflection (cause all I get is a flickering mess)

Already possible to have refractions without reflections. I forgot the code, I think it was dprefract or something. I already tried it out in the past and it worked fine.

Anyway, I spoke with divVerent about this. He doesn't see the cubemap deformation ever happening (not sure why). As for the self-illuminated bump maps, he mentioned they would require cone mapping (or something like that) in the engine, instead of the current system. Which would be very hard to do, and it's in doubt if anyone ever will code this in the engine Sad

RE: 2 rendering changes I'd love to see in Xonotic - frostwyrm333 - 08-31-2012

MirceaKitsune, you mean something like self-shadowing for normal maps?
To tell the truth these dynamic lighting/shadow tricks are quite rare anyway, you see them only with some guns and only for a fraction of second. Is there even a map that uses lights that switch on/off or rotate? Probably not because this would be seen only by people with real time world etc etc.

RE: 2 rendering changes I'd love to see in Xonotic - hutty - 09-01-2012

the mapper can force individual real time lights to work even if the setting is turned off (glowplant near strength has a shadow one ... redplanet has a blinking one ... and techassault too)

to make a rlight "turn off" you would have to move a invisible shadow casting box in front of it ... (there is not way of telling them to just "turn off")
the issue is rlights that cast shadows usually lower fps alot ... especially if they are big ones ///

RE: 2 rendering changes I'd love to see in Xonotic - frostwyrm333 - 09-02-2012

So is it possible to make something alien-like, like a dark room with red light that "turns off" sometimes? Shadows would not matter because it would be pitch black anyway.

RE: 2 rendering changes I'd love to see in Xonotic - hutty - 09-02-2012

the shadow casting is needed for the lights to "turn off" ... otherwise they will shine through the thing you move in front of them ...

flickering lights are diffrent though ... there is a setting for the rlights to set them up with a bunch of flicker patterns ... those don't need shadows ...