AgX - New alternative SDR tone mapper

[another_commander]

Following up on the discussion regarding SDR tone mappers here, I just wanted to let you know that a new and improved over ACES tone mapper is undergoing testsing and has been included in the latest pre-release build 033832b. It is the AgX tone mapper and, more specifically, its Punchy variant, designed for higher contrast and saturation over the default standard AgX, which sometimes feels somewhat washed out, especially when compared to the typical filmic tone mappers we have been exposed to until now.

AgX is more recent than ACES and although not as contrasty, it has better color accuracy representation. ACES tends to shift red hues to orange and yellow at high intensities, but AgX maintains hues regardless. It also has a gentler ramp-up to highlights color desaturation for a more pleasing aesthetic. Right now AgX is present but dormant in the Oolite shaders. To activate it for your own testing, open oolite-final.fragment in the Shaders folder and change the line #define OO_TONEMAPPER_AgX 0 to #define OO_TONEMAPPER_AgX 1.

And since we can't possibly talk tone mappers without images, here are some comparison shots. First is ACES followed by AgX Punchy.

Test Pattern:



In-game:





















In the last shot you can see ACES shifting hue to yellow when very bright reds are shown. This is not the case with AgX.

This tone mapper is available for both Windows and Linux, as it is SDR-only.

[Redspear]

Subtle but significant. Good work and thanks!

[Cholmondely]

Just to say, a_c, I'm utterly convinced that your incessant plugging away, improving the graphics over the past few years, is the main reason why there are now some several thousand people who have watched Phkb's new film on Reddit.

It will be interesting to see how many downloads are generated! There has already been one who confessed (the chap who discovered that Oolite works with SteamDeck).

I've still a few more to do - posting on Reddit is pretty laborious.

[another_commander]

Thank you both guys. I am still not entirely happy with the excessive saturation AgX Punchy generates. It is evident in the images posted and much more so during gameplay. The parameters of the tone mapper are exactly as its spec states, but the result seems "just too much color, bro".

The variable controlling this is sat inside the agxLook function. For Punchy it is set to 1.4, but personally I like it a lot better with a lower value, like 1.1, which approaches the ACES saturation. I would be interested to hear opinions on this from those who had a chance to test it.

Also, I will confess that I am very fond of the higher contrast ACES generates, which I find very fitting for a space game. AgX is more neutral in this regard - not a problem in any way, it is just differences between tone mappers and at the end of the day you pick what your eyes enjoy the most. There is also the consideration of HDR on Windows, where ACES is also used. Switching over to AgX for SDR would create some distance between the looks of SDR vs HDR.

Because of all the above, I think we'll just keep the AgX option available but not default for the time being. It is there for anyone wishing to use it and it is very good. Maybe in the future we could turn this into a user selectable option too, who knows. But I for one, am glad that we have it since it is presently considered as one of the top - if not the top - color management systems out there.

[Redspear]

I am still not entirely happy with the excessive saturation AgX Punchy generates. It is evident in the images posted and much more so during gameplay. The parameters of the tone mapper are exactly as its spec states, but the result seems "just too much color, bro".

I think (which is often the start of things going wrong...) that it's easy to forget that we typically compare still images rather than the more dynamic in-game experience, so it's interesting that you mention gameplay in particular.

I say forget because I think we all know this and yet there's such aparent utility in comparing stills in order to get a 'proper look' that we can fixate on things that we might experience differently in game. Oolite's a space game however, so when you're viewing a slowly rotating planet texture or a background nebula and you're just cruising along then the dynamism of the game is relatively low compared to a thargoid ambush for example.

Maybe 'too much colour' isn't just your perception, rather it's what boosts the experience and seems much less of an issue the more you play. It's almost like memory vs reality in that colour in particular can convey emotion or intensify an experience in a way that might not necessarily be entirely realistic. To compensate for not really being there we're fed a heightened experience to some of our senses to diminish the fact that others are barely involved or even feeding us contrary information.

It could be an interesting (but time consuming) experiment to play for a week with a tad 'too much' colour and then turn it down to 'realistic' and see if you missed it. We're very much in the realm of subjectivity here of course just as I myself find that as TVs get better and better it's becomes harder and harder to get a picture that consistently feels 'just right'.