Broken Behavior for WorldScape3D world_background NONE/NOISE

[cas380]

Tested versions

v26.3.beta.1.official [335d159]

System information

Redot v26.3.beta.1 - Windows 10 (build 19045) - Multi-window, 2 monitors - Vulkan (Forward+) - dedicated NVIDIA GeForce RTX 3060 (NVIDIA; 32.0.15.6094) - AMD Ryzen 9 7900X 12-Core Processor (24 threads) - 30.95 GiB memory

Issue description

I saw #1329 make it into Redot 26.3-beta.1 and went to try it out. I'm seeing unexpected and inconsistent behavior when world_background is set to NONE or NOISE.

NONE should remove all regions that have not been added; instead, different patterns are produced among the excluded regions:

NOISE should randomize the regions that have not been added as if to surround the world with mountains; instead, only patterns of regions have noise:

There's also a clear cutoff at the edge here, even though none of these regions have been or were ever included:

Results will vary as you add and remove regions.

Steps to reproduce

1. Create a scene with WorldScape3D as the root (or Node3D as the root and add WorldScape3D to it)
   • You will have to select a terrain data directory
2. Save the scene
3. Set the WorldScape's material.world_background to Noise or None
4. Add and remove regions to see odd behavior

Minimal reproduction project (MRP)

MRP: world_scape_mrp.zip

Interestingly, on first load, the NOISE terrain looked correct. Then I added a region.

[OldDev78]

There are a number of issues related to the region size, which culminates in this weird behavior. Also, very telling, the world_noise shader has an interesting comment //TODO: Offset/scale UVs are semi-dependent upon region size 1024. Base on v_vertex.xz instead