TDM Fresnel Mod

[nbohr1more]

8 hours ago, peter_spy said:

I'm for specular behaving like typical specular and being relatively inexpensive, instead of faking specularity with cubemaps because... reasons?

So not a fan of HL2 specular eh?

https://developer.valvesoftware.com/wiki/$envmap

This is what @J.C.Denton was probably aiming towards which is not too out of the ballpark for a 2010 design.

[peter_spy]

This is not a specular hotspot, this is a cubemap reflection. I don't like mixing those up. I like how this is done automatically in PBR setups, where one gradually turns into another with respective roughness values. In non-pbr workflow, I prefer to control both separately. Besides, they don't even react to light in the same way.

Edited March 20, 2021 by peter_spy

[nbohr1more]

I went back to the old GLSL thread and tested my modifications in the ambient_light test map for further calibration.

I then tried to run this map in 1.07 but apparently it's assets are too new.

I then installed 2.05 for comparison. While goofing around I compared Caduceus of St Alban between 2.05 and 1.07 and noted that the fresnel effect is stronger in 1.07 and the faked reflections in the gold statues is gone as well as other reflective ambient behaviors. Either that part of the ambient shader was removed between 1.07 and 2.05 or the darker env/gen cubemap in standalone has made the effect less prominent. Since my goal was to get the 2.05 ARB look back, it is not too urgent to add this cubemap back but it might be a nice stretch goal to have a true 1.07 legacy mode. On comparing Caduceus between 1.07 and my shader, I would humbly accept victory so anything further is just a bonus.

[nbohr1more]

I am uploading this here for safe keeping:

interaction.ambient.fs.glsl

I have mostly ported the entirety of the fresnel shader design from our own standard lights to the ambient light.

The specular response is significantly improved. Metals look like metal under ambient lighting again!

This was created using the SVN build so it will probably only work for Dev builds. I will evaluate how difficult it will be to back-port to 2.09 ( probably not too much work ).

To test it out, either unzip the tdm_base01.pk4 and overwrite the same file under /glprogs/stages/interaction or create a /glprogs/stages/interaction/ folder in your darkmod directory and save this file there. ( basically use any valid Doom 3 shader mod install process ).

[nbohr1more]

tdm_base01.pk4

Here is a package ported to 2.09.

I reconciled the fresnel and SSAO by having the fresnel effect set to "min" between the darkest fresnel pixel

and the darkest SSAO pixel. While I am sure there are cases where fresnel is brighter than AO in a realistic simulation,

TDM has so many textures and assets with baked AO or shadows do letting SSAO "win" the darkest pixels

seems to better match the art style better.

[nbohr1more]

A few screens:

Spoiler

 

 

 

 

 

 

 

 

 

 

[nbohr1more]

I tried to incorporate the old sky color \ ground color paradigm from the 1.03 shader but it seems that the code support

for "world up" direction may have been dropped?

Oh well, here is a new version. Color matched and specular tuned to even further have the same specular response as regular lights so everything is now uniform. Also, I trimmed off at least 4 operations including a sample so this should be more optimized.

tdm_base01.pk4

[nbohr1more]

New screens:

 

Spoiler

 

 

 

 

Here is a direct comparison:

Default ambient:

 

Fresnel Mod:

You can see that the new specular behavior preserves the subtle specular texture work on the hands.

 

 

 

[nbohr1more]

Somewhat disappointingly, the advantages of this mod are rarely seen in the best looking missions.

 

This is because many mappers have approximated this look by augmenting their maps with "bounce lights" since

the release of "Sir Talbot's Collatoral" so you almost always see the same specular effect in ambient lighting as with

real lighting because most maps "always use real lighting" for ambient locations anyway.

 

Having this new ambient behavior should reduce the need to place bounce lights around

and thus should save a little performance as well as mapping efforts.

[nbohr1more]

A small bug crept into the last build. Here is a new one.

The latest one is as trim as I think I can get without utterly replacing all original specular code.

Enjoy!

tdm_base01.pk4

[nbohr1more]

I got sick of messing around with the ported code, and instead tuned the specular in the current design and added fresnel.

The result is smaller cleaner code and it looks better as wellinteraction.ambient.fs.glsl

[nbohr1more]

Here is the shader back-ported to 2.09b tdm_base01.pk4

And here is a final tweak ( also included above ) for the 2.10 dev build interaction.ambient.fs.glsl

[nbohr1more]

One of my long term wishlist items has always been that the ambient have a little distance based darkening so that background items are darker than foreground. I have finally achieved this effect via my own efforts:

 

[nbohr1more]

 

[nbohr1more]

Here are some comparisons:

Default:

New:

Default:

New:

Default:

 

[nbohr1more]

Default:

 

 

[nbohr1more]

New:

[nbohr1more]

The new 2.09b build :

tdm_base01.pk4

2.10 dev:

interaction.ambient.fs.glsl

Other features?

Improved darkening for the underside of normals to restore some detail lost by fresnel brightening

Fresenel now responds much better to specular variation

Specular is clamped to 96% of ambient brightness rather than using lots of complicated clamp factors ( more optimized)

 

 

[nbohr1more]

Default:

New:

[nbohr1more]

Default:

New:

[vozka]

Are there any plans to integrate this into master? I love how it looks.

[nbohr1more]

This is my personal quest to make an ambient that is equal or better than the one from TDM 1.03 to 2.05.

The plan is to eventually add something like this as a legacy mode or default mode.

Ideally this work would be superseded by a move to true PBR that would incorporate similar features but would be

more "physically correct". My work is mostly artistic in nature so it is not quite good enough yet though I am trying

to make it more rational and mathematically sound.

[Oktokolo]

Looks good, but the whole scene seems to get naticably brightened too.
Not sure, whether just playing on slightly less gamma would fix that.

[nbohr1more]

The grass has a decent amount of specular so the brighter specular hightlight causes the scene to look brighter overall.

I have worked to modulate against that effect a little.

[duzenko]

What about lightgem? I remember that being major drama trigger. It breaks missions!11