Creating Standalone Shadowmask Node separate from Lightmap GI

[Kekitopu]

The new ShadowMask feature in Godot 4.4 allows you to bake distant shadows, preventing them from disappearing when the camera is far away. Currently, the only way to bake ShadowMasks is through the Lightmap GI node, which also bakes indirect lighting into an EXR texture.

If you check the files generated after baking, you'll notice that the EXR lightmap texture takes up significantly more disk space than the ShadowMask texture. In one of my levels, for example, the lightmap texture was 90MB, while the ShadowMask was only 8MB.

I think having the option to bake only the ShadowMask would be a great addition. It would help create more lightweight games if you don't need to use GI. and allow developers to use other GI solutions, like SDFGI, alongside ShadowMasks.

[Calinou]

I think godotengine/godot#102483 will address this by letting you use a lower-resolution lightmap texture compared to the shadowmask. You could set the texture resolution factor to something like 0.01 so that the lightmap texture is 100 times smaller on each axis (therefore using up 10,000 times less space than previously).

See also #7590, which can give you a shadowmask-like effect without needing to bake lightmaps at all.

and allow developers to use other GI solutions, like SDFGI, alongside ShadowMasks.

For this particular case, it would be best to use the SDFGI data to draw SDF-based shadows in the distance. However, since SDFGI is getting replaced at some point in the future, this is on hold.

[Kekitopu]

The way trackmania does it is nice but shadowmasks can also be overlayed with the dynamic shadows making them appear smoother, this is something that can already be done with lightmap GI, If I remember correctly this is also how shadows work on CSGO because dynamic shadows on that version of source engine are always sharp.

I mentioned SDGI just as an example, but another would be VoxelGI, the baked data for Voxel GI is very small in comparision to the EXR, and it would be nice to be able to use VoxelGI alongside ShadowMasks.