2D Light Occlusion appears broken in 3.5.2 and also 4.1

[Bat-Computer]

Godot version

3.5.2 and also 4.1

System information

Windows 11, GLES3 (3.5.2) & Mobile (4.1)

Issue description

2D Light Occlusion doesn't work as intended in both 3.5.2 and also 4.1.

Creating a simple scene with a tilemap, tiles set to occlude
(This also happens when using a Light Occluder2D on sprites)
Adding a PointLight2D with texture and shadows enabled.

In Godot 3.5.2 when you enable Shadow the texture turns to a block:

In Godot 4.1 shadows work until the Light2D moves over the occluded tile or sprite, then the object becomes lit, when it should stay dark.

Steps to reproduce

Creating a simple scene with a tilemap, tiles set to occlude
(This also happens when using a Light Occluder2D on sprites)
Adding a PointLight2D with texture and shadows enabled.

In 3.5.2 move enable shadow, the texture turns into a block.
In 4.1 shadows work until you move the 2D light over the sprite/tile, then it becomes illuminated when it should stay dark.

Minimal reproduction project

Test Occlusion Tilemap Shadow 3.5.2.zip
Test Occlusion Tilemap Shadow 4.1.zip

[kleonc]

In Godot 3.5.2 when you enable Shadow the texture turns to a block:

In 3.5.2 it works as in 4.1, you just have an occluder on both tiles:

After removing it from one tile, saving, and somehow triggering a redraw (seems like this doesn't happen automatically on removing an occluder), e.g. by drawing another tile or reloading the scene, then it looks like this:

---

In Godot 4.1 shadows work until the Light2D moves over the occluded tile or sprite, then the object becomes lit, when it should stay dark.

Not sure whether this is expected/intended or that's indeed a bug (hence marking as both bug/discussion 🙃).

[Bat-Computer]

In previous versions the light would not illuminate the occluded tile/sprite when the 2D light overlaps, at least it seems this way in this tutorial from 4 years ago (Godot 3.1). In the tutorial it is quite straight-forward to get it to work, nothing extra is done.

https://www.youtube.com/watch?v=QsCfx-jjS0U (edit: fixed the link)

[kleonc]

In previous versions the light would not illuminate the occluded tile/sprite when the 2D light overlaps, at least it seems this way in this tutorial from 4 years ago (Godot 3.1). In the tutorial it is quite straight-forward to get it to work, nothing extra is done.

https://www.youtube.com/watch?v=QsCfx-jjS0U

Skimmed through that video, I haven't seen the light ovelapping an occluder at anytime.

Tested MRP in 3.1.stable.official, behaves the same as 3.5.2 but buggier on the edges:

And with the occluder removed from one tile:

So I'd assume the claim that in the previous versions lights were not affecting the overlapped occluders is false.

[Bat-Computer]

Maybe something was lost in translation here?

The reason I 'claimed' that this worked as intended in 3.1 (4 years ago) was because the YouTube video was posted at that time and it says Godot v3.1 in the title. It obviously worked when the tutorial was created, you can see if you watch the video or look at the screenshot I provided from the tutorial (It looks like it was created in Ubuntu Linux).

Here's a time stamp on the video (5:38), when the shadow is enabled you can clearly see the tile is not illuminated by the light.

In my humble test with v3.1 I wasn't able to get the light texture to appear once the shadow was enabled - it just turned into a block and didn't cast shadows, so I couldn't varify it working at all.

[Calinou]

• Related to Unexpected behaviour of overlapping occluders  #72983 and Light2D inside Light Occluder lights it up #44236.

There's a known issue in Godot 4 where you have less control over light/shadow display compared to 3.x, but I can't find the link to that issue right now.

[ZigZaggh]

Would love to see a fix for lights inside occlude shapes, I have scenes casting shadows, but as soon they move in front of a light hanging on the wall behind, the scene is lit up instead of the light just being completely blocked.

[Bat-Computer]

I have a simple workaround for the light going through the tilemap occlusion, it might not me ideal for everyone, but you can just duplicate the tilemap and add it on top of the original tilemap - sort of like a mask. You'll should put it on a different collison layer, but it works well.

[ZigZaggh]

Thank you, that works perfectly 👍