Gouraud shading for models?

YouTube · Post by **Nash** » Tue Jan 17, 2006 2:37

The 3-d models look a little flat in GZDoom at the moment. Do you have any plans to add gouraud shading for them?

Post by **Graf Zahl** » Tue Jan 17, 2006 9:50

That would need illmination by dynamic lights - which hasn't been implemented yet.

YouTube · Post by **Nash** » Wed Jan 18, 2006 22:25

Come again? Aren't the models already illuminated by the dynamic lights? Or am I misundertsanding what you said?

The lighting seems correct for me...

Post by **Graf Zahl** » Wed Jan 18, 2006 23:29

The models are illuminated as a whole. In a perfect system they should be lit per vertex. To get Gouraud shading to work I need different light levels at different vertices. Unless that isn't the case there won't be any difference.

YouTube · Post by **Nash** » Thu Jan 19, 2006 0:02

I see... hope you implement it someday.

jaquboss · Post by **jaquboss** » Thu Feb 02, 2006 15:48

rather old topic but...
I think you can load model normals and use glLight() as it looks perfect and you won't have much problems

unless you need Q3 shader system

then you must do custom lighting code

SlayeR · Post by **SlayeR** » Fri Feb 03, 2006 2:49

Well as long as they don't have shading when they aren't lit by a dynamic light. Doomsday does that and it's one of the factors that makes them look less like the sprites. IMO the old old ZDoomGL models looked more like the originals because they didn't have the 'shiny' effect the Doomsday ones have.

DaniJ · Post by **DaniJ** » Fri Feb 03, 2006 3:46

Well as long as they don't have shading when they aren't lit by a dynamic light. Doomsday does that and it's one of the factors that makes them look less like the sprites. IMO the old old ZDoomGL models looked more like the originals because they didn't have the 'shiny' effect the Doomsday ones have.

Care to explain that further?

SlayeR · Post by **SlayeR** » Sat Feb 04, 2006 6:41

I don't have the doomsday models to test with at the moment but from what I can remember they were always lit by some ambient light, most noticable on spinning items/weapons etc.

DaniJ · Post by **DaniJ** » Sat Feb 04, 2006 13:30

What you are describing sounds like the "world light". In 3D, models should ALWAYS be lit as without that there is no definition of shape and form (like GZDoom currently).

When there are no dynamic lights in the vicinity, and neither the floor or ceiling are dominate sources of ligth - then models are lit using "world light". This is one of those instances where 3D graphics breaks the "real-life rules" on purpose due to the simplistic lighting model used in DOOM.

However, in 1.9.0 we have the new BIAS lighting model. This means that models will be lit by all light sources as they are "infinite sources of light" using line-of-sight calculations (in the current beta this is done per mobj but it will be replaced with a per-vertex system). This will allow lights behind bars to cast "approximated shadows" onto everything in the scene (including the models themselves)

Sector light levels are converted into a 3D ambient lighting grid. However there is a mechanism in place that "preserves" very bright sectors so that they still have a definite shape. As the algorithm developes, I suspect these sectors will be extracted and enhanced using another algorithm (similar to Fakeradio) that will blend the edges of these sectors too.

Post by **Graf Zahl** » Sat Feb 04, 2006 13:40

Welcome to an engine that is no longer Doom. I know precisely why I'll never add such features.

DaniJ · Post by **DaniJ** » Sat Feb 04, 2006 14:24

Welcome to an engine that is no longer Doom

Oh come on. Sure the renderer is "no longer Doom" (it is definetly not Quake either, it has its own very distinctive look that isn't a million miles away from Doom) but the same can be said about GZDoom. The game logic, AI and all the other stuff is exactly the same in jDoom as that in DOOM.exe

As with ALL the eye-candy in Doomsday - you can always disable it and revert to a renderer that looks pretty close to DOOM.exe (minus some crazy rendering hacks that arn't supported yet).

Both ports have changed so much about different aspects of the original engine that it is pointless to try to say which one is more like Doom. The fact that GZDoom looks like Doomsday (with most of the eye-candy disabled) makes your statement rather bewildering.

Post by **Graf Zahl** » Sat Feb 04, 2006 15:16

DaniJ wrote: As with ALL the eye-candy in Doomsday - you can always disable it and revert to a renderer that looks pretty close to DOOM.exe (minus some crazy rendering hacks that arn't supported yet).

Thank god!

All that eye candy makes my eyes hurt.

But for me the GL renderer has always been a means to an end (i.e. make it easier to add some gameplay features like 3D floors) than the end to all means. I wouldn't have a problem with playing Doom in software mode if it wasn't so much slower at higher resolutions. True color is also nice (...but I still have to get that goddamn fog right. That one annoys me most.

)

DaniJ · Post by **DaniJ** » Sat Feb 04, 2006 15:28

Graf Zahl wrote:I still have to get that goddamn fog right.

I can sympathise.

Unfortunetly, OpenGL's lighting equation does not lend itself well to recreating the "DOOM-look" when it comes to fog. In Doomsday we haven't really bothered with fog yet at all because of this and just stuck to using the duck-simple OpenGL fog extension (now that we have full per-vertex lighting going on, I'm sure skyjake will be able to generate some far better (per-sector or even volumetric) fog effects, without using "funky" additional pass solutions requiring extra polys on twosided lines).

Post by **Graf Zahl** » Sat Feb 04, 2006 16:03

It would be sufficient if one could specify custom depth equations to get Doom fog right. The default linear and exponential fog equations are far too limited IMO.