Add a project setting to use nearest-neighbor filtering for shadow maps

[BecketTocci]

Describe the project you are working on

A pixel art 3D game.

Describe the problem or limitation you are having in your project

The shadows in 3D are currently always soft. In my game, I would like pixelated shadows. I have tried several settings, and none of them work correctly for my use case.

Describe the feature / enhancement and how it helps to overcome the problem or limitation

Add an option in Rendering/Lights and Shadows/Directional (and Positional) Shadows/ Soft Shadow Filter Quality
to disable shadow filtering altogether.

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

This will only take a few lines of code in whatever function samples the shadows. I have never contributed to Godot, so I don't know exactly what to say here.

If this enhancement will not be used often, can it be worked around with a few lines of script?

No. I have tried several times and this is either impossible without modifications to the engine itself or very hard.

Is there a reason why this should be core and not an add-on in the asset library?

There are a lot of games with stylized art direction these days, particularly pixel art.

[clayjohn]

This is already supported in the project settings. Just set the filter quality to "hard" to disable shadow filtering

[Zireael07]

That isn't clear at all. If it totally disables, it should say "Off" not "Hard" (IMO, I'm not a native English speaker)

[Calinou]

• Related to Add a project setting to use hard cutoffs for shadow map rendering #9445.

This can be done easily, but the issue is that pixelated shadow maps generally only look good if you snap them to texel coordinates that match world textures. Minecraft shader packs that have real-time shadows typically have an option for this, which makes the pixelated shadows seem a lot more grounded with the rest of the world. However, this is nontrivial to implement in games where texel density is not known in advance and isn't the same on all materials (which is what nearly all games do).

You can see an example of this on the screenshots in #8671 (comment).

That isn't clear at all. If it totally disables, it should say "Off" not "Hard" (IMO, I'm not a native English speaker)

Hard shadow filtering still uses bilinear filtering, which means shadow edges don't actually appear perfectly sharp. It's a good choice to emulate shadow maps seen in early 2000s games, but it won't give you the chunky shadow appearance OP is looking for.

Hard shadow filter + Bilinear filtering	Hard shadow filter + Nearest-neighbor filtering

[BecketTocci]

This can be done easily, but the issue is that pixelated shadow maps generally only look good if you snap them to texel coordinates that match world textures. Minecraft shader packs that have real-time shadows typically have an option for this, which makes the pixelated shadows seem a lot more grounded with the rest of the world. However, this is nontrivial to implement in games where texel density is not known in advance and isn't the same on all materials (which is what nearly all games do).

You can see an example of this on the screenshots in #8671 (comment).

Okay. We could also add a setting to use texels at all, but make sure to say it's best to turn it on if you're using low resolution shadow maps and such in the shadow filter settings documentation comment.