TDM Fresnel Mod

[nbohr1more]

It is my understanding that view dependent effects like fresnel and specular do not influence

the interior of the lightgem octahedron very much so it's doubtful that the effect will alter playability in missions.

 

That said, it may make some players feel that the immersion is lower since they see a brighter world but the

effect is not correlated to the lightgem level.

 

All that said, I am still working on better tuning of the brightness.

[nbohr1more]

This one is a little less dramatic but also has removed almost all crazy fudge numbers in favor of doubles , quarter, halves.

Not quite sure about how it dries up fresnel a little too much on bright stone but it is still pretty charming.

interaction.ambient.fs.glsl

[nbohr1more]

Here is a 2.10 build:

https://www.moddb.com/mods/the-dark-mod/addons/fresnel-mod-210-beta

The instruction count has been further reduced.

Comparisons:

Default:

Just the fresnel and Specular effect:

Fresnel and Distance darkening:

Fresnel + Distance Dark + SSAO

 

Default + SSAO

 

[HMart]

IMO the fourth one is the best, SSAO and distance darkening really make the scene depth popup, fantastic work. 

[nbohr1more]

A little preview of the ongoing work:

Since 2.11 has some major changes to shader architecture, I had to rebuild my design.

In addition to restoring all my basic features, I gave considerable thought about how finicky and full of

fudge factors my last design was.

For the longest time, I have been unhappy about what I call the "velvet effect" on diffuse surfaces. This seems to happen

because the original design has the fresnel multiplied by the diffuse. I went to great lengths to achieve the following conditions:

1) Set a dry looking default fresnel for diffuse textures

2) Make specular fresnel match the look of the specular reflections from above

3) Don't make everything shiny ( an issue that was caused by fresnel in 1.03 due to a default minimum boost in specular to everything )

4) Avoid the velvet effect

Happily, I have achieved all the goals and then some.

How did it do it?

Like some of my earlier designs, there are two different fresnel equations for specular vs diffuse.

Diffuse has a hard-coded low power constant which spreads the effect wide over surfaces rather than being a rim effect

The specular fresnel power value is initially high but is multiplied by the specular texture causing shinier values to have tighter fresnel that looks more like specular

How did I apply the fresnel effect to diffuse without multiplying it or causing the velvet effect?

I multiplied the diffuse fresnel by 1.0 minus the specular texture ( inversion ).

This caused all the shiny areas to remain dark but brightened low or no specular areas.

This still was too foggy when added to the top of surfaces so I then also multiplied the results from

the inverted specular pass with an inverted diffuse map. This cause the effect to retain most of the diffuse features without

becoming too high contrast or causing neutral textures to glow.

Finally, probably the biggest change was that I was able to adapt one of stgatilov's changes to make the entire underside of structures darker the way it used to be in 1.03. This has a dramatic improvement to scenes like the one above.

Here are the 2.11 files ( currently requires building from SVN source ). I will attempt to back-port my improvements to the 2.10 shader a little later.

 

 

tdm_interaction.glsl

interaction.ambient.fs.glsl

Since the new dev build is out ( dev16617-10107 ) here is a pack file to place in your darkmod dev build folder:

https://www.moddb.com/mods/the-dark-mod/addons/211-alpha-dev-build-fresnel-mod

 

Edit:

Woo! I got the down-shading to work in 2.10:

        vec4 worldN2 = normalize( params[var_DrawId].modelMatrix * vec4(N, 0) ) ;
        vec3 worldL2 = vec3(0, 0, 1);
        float NdotL2 = dot(worldN2.xyz, worldL2);
        float downshading2 = min (( NdotL2 + 1.38 ), 1.0 ) ;

gotta cleanup the rest of the shader design and I'll post a new version.

 

[nbohr1more]

Here is a backported verion for 2.10

https://www.moddb.com/mods/the-dark-mod/addons/fresnel-mod-210

EDIT:

I finally figured out how to fully divorce the diffuse and specular in 2.10.

Attaching here for safe keeping:

interaction.ambient.fs.glsl

I'll upload a new pack file to moddb once I am done testing and tuning.

[nbohr1more]

As promised, a new 2.10 build is up:

https://www.moddb.com/mods/the-dark-mod/addons/fresnel-mod-210

[nbohr1more]

Here are some new comparisons:

Default:

New Fresnel with underside darkening:

New Fresnel with SSAO:

[nbohr1more]

Default :

New Fresnel :

New Fresnel with SSAO:

 

[nbohr1more]

A few beauty shots:

 

[snatcher]

Posts like this makes me appreciate TDM and the people behind it even more. We are in good hands. Respect.

Dear @nbohr1more,

I don't know a thing about the fine detail being discussed here but I am thrilled by the passion you put into this mod(ification). Since we can have several instances of TDM running in parallel, will you kindly suggest a mission (TDM 2.11), and perhaps a precise location or locations, for me to check with and without Fresnel and form an opinion?

Thanks in advance.

[nbohr1more]

Make sure to use the version here:

https://www.moddb.com/mods/the-dark-mod/addons/fresnel-mod-211-unofficial

The most dramatic place to check this out is in the start area of the mission "Caduceus of St Alban".

That said, any mission with large amounts of flat ambient lit surfaces that have the same texture over vast swaths of the scene will see dramatic improvement.

The Vengeance for a Thief ( really, any Sir Taffsalot ) missions are particularly improved by this one.

[wesp5]

May I ask why this is not a part of the core game? I'm pretty sure that you are one of the main developers, are you not?

[peter_spy]

Because it's a visual tweak based on a personal preference that would actually make it harder to create maps and content for TDM.

Once TDM has PBR support, such tweaks won't be necessary, as fresnel response will be calculated correctly at material level.

[snatcher]

I see.

Fresnel changes the frame in many different ways. With Fresnel ON everything is a tad brighter but I get to see more refined shadows in the stone structure. In addition, and as promised, brightness gets reduced at long distances.

I will let experts decide what's best because I am unable to tell (a few minutes into the mission) if the experience is improved with Fresnel on or off. My brain isn't trained for this kind of processing.

(I suggest to download the images and compare them side by side locally)

Fresnel OFF:

Fresnel ON:

Fresnel OFF (White Point Adjusted):

Fresnel ON (White Point Adjusted):

[MirceaKitsune]

Was going to ask why in the world such a nice effect isn't included in vanilla but PeterSpy answered that. Can't wait for TDM to finally have PBR with this effect and more! Let us dream for 2.12