Repository: godot
Issue: PointLight2D shadow_filter = SHADOW_FILTER_NONE still applies a filter in Forward+ and Mobile rendering when it shouldn't
Labels: bug,topic:rendering,needs testing

### Tested versions

Doesn't work in 4.3-stable (Didn't work in previous versions of v4 at least as early as 4.2-stable either)

Works as intended in 3.6-stable

### System information

Godot v4.3.stable - openSUSE Tumbleweed 20241216 - X11 - Vulkan (Forward+) - dedicated AMD Radeon RX 6600 XT (RADV NAVI23) - AMD Ryzen 7 5700X 8-Core Processor (16 Threads)

### Issue description

In v3.6, 2D lights don't have any shadow acne. In v4.3, there are unwanted artefacts when a light casts a shadow, which as @arkology has pointed out is `shadow_filter = SHADOW_FILTER_NONE` still applying a filter.

The issue is present with Forward+ and Mobile renderer, but mostly cleared up in Compatibility.

It shows up more obviously when the game is running

Here is a picture from the most recent MRP I've uploaded
![Image](https://github.com/user-attachments/assets/c83816c5-6d75-4348-8a31-fa33cbaed697)
The shadows are cast from Light 2

![Image](https://github.com/user-attachments/assets/2441e84a-c557-4726-8a73-23792c04b999)
The image above is taken from v3.6 ^
This shows the pixel perfect shadow casting with no acne from a Light2D
This is the effect I would like to achieve again

 ![Image](https://github.com/user-attachments/assets/1bbdbcba-5dd2-4809-b384-30fe6b25c90a)
This image is from v4.3 ^
This shows the acne forming a gradient on the edge of the shadows cast from a PointLight2D

![Image](https://github.com/user-attachments/assets/c6df014d-98a6-486d-b2d5-207d85860445)
Another image from v4.3 ^
This shows the same artefacts (the gradient is a different colour as I've been fiddling to try lower it as much as possible)

Increasing the Shadow Atlas Size to maximum helps a little bit, but does not fix the problem.

I've included images from both MRPs showing the issue in a comment below


### Steps to reproduce

Works in both v4.3-stable and v3.6-stable 

1. Set up the project by setting:

> Viewport width/height = 480/270 (Low res is important)
> Window override width/height = 1920/1080
> Stretch Mode = Viewport
> Stretch Aspect = Keep

3. Create a 2D scene
4. Add a ColorRect and set it to a colour darker than white (eg grey, 707070)
5. Add a PointLight2D in v4.x, or Light2D in v3.6, enable shadows
6. Set Texture to this [Image](https://github.com/user-attachments/assets/27dd7763-5318-4233-8278-107a8227f08c)
Or a similar sized sprite, where White is Light, and Transparent is no light.
7. Add a LightOccluder2D and an occluder polygon of whatever shape.
8. Make sure the Light is overlapping the occluder so there are shadows being cast,
9. Launch the game

Additional steps to get a better showing of the issue:
10. Add an extra PointLight2D, with a script to follow the mouse
11. Add a CanvasModulate with a dark colour
12. Launch the game and you'll see artefacts like the first image in this post


### Minimal reproduction project (MRP)

NEW MRP version for 4.x is here -
[NEWShadowAcneGD4-3MRP.zip](https://github.com/user-attachments/files/18362758/NEWShadowAcneGD4-3MRP.zip)

OLD version:
This contains both the 4.3 and 3.6 versions. The 3.6 version needs to be opened with 3.6-stable and not a 4.x version
[ShadowAcneGitUpload.zip](https://github.com/user-attachments/files/18352893/ShadowAcneGitUpload.zip)