[Bug, 1.16.5] Severe Visual Oddities (with and without shaders) and Odd Performance

[ThisNekoGuy]

Description of Issue

After an amount of time, the world reloads all textures and doesn't reload properly, leaving the world semi-transparent.

I expect that this wasn't intended at all? It's also present in the two prior builds for 1.16.5 with their corresponding Forge versions.

Details: Some objects and mobs are seen through other objects; textures turn to different colors or go transparent; and, seemingly only when a shader is active (tested with Sildurs and BSL), the world will decide to refresh itself (example of this is the last Debug screenshot below, where the world looks like it's on drugs).

Performance is also unexpectedly bad sometimes (depending on the area) for my hardware with no shaders on and only the default resource pack active.

Increasing the available RAM used (even at 16GBs) doesn't alleviate the problem.

Steps to Reproduce

1. Launch the game with Optifine; mods are optional and don't affect the result
2. Load a world (I loaded an online server for testing)
3. Depending on the area the world may seem normal but specific objects such as signs, chests, beacons, mobs underground, etc may already appear through other objects
4. Depending on whether or not you have a shader active, if you don't: this state will persist basically indefinitely; if a shader is active, after a set amount of (rather unpredictable but short) time, the world will refresh and leave you staring at partially loaded chunks, mobs, and the void.

OptiFine Version(s)

• OptiFine HD U G8
• OptiFine HD U G7
• OptiFine HD U G6

Installation Method

1. Downloaded the jar(s)
2. Ran ATLauncher
3. Selected Edit Mods button for the 1.16.5 instance I was using
4. Selected Add Mod button and added it as a mod (that goes into the mods folder)

Fabric/Forge Version

-For G8: Forge 36.1.0 -For G7: Forge 36.0.42 -For G6: Forge 36.0.0

Other Installed Mods

Log Files/Crash Reports

Log file example Debug Log File

F3 Debug Screenshot

Prior Testing

• Does this happen in Vanilla without OptiFine? No

If you've installed using Forge/Fabric:

• Does this happen without other mods installed?
  • Only OptiFine and Forge Yes
• Does this happen without any mods at all?
  • Only Forge/Fabric by itself. No
• Does this happen in OptiFine standalone? ?
• Does this happen in Vanilla without OptiFine? No
• Have you tried using a binary search to find which mods cause this issue? Yes
  • To find conflicting mods, split your mods into 2 groups (not including OptiFine/OptiFabric, obviously). Remove one group, and test in-game. Keep the group that has the problem, and repeat until no more mods can be removed without the issue disappearing.
  • Does the issue still happen with only the remaining mods installed? Yes
    • Forge/Fabric and remaining mods, without OptiFine No

Additional Information

OS: (Arch) Linux Linux Kernel: 5.11.22-159-tkg-upds CPU: Ryzen 3700X RAM: 32 GBs @ 3600 MHz GPU: 2080 Ti GPU Driver: 460.80

[Regnander]

This is a very detailed and well-written bug report. Good job!

[KaiAF]

Try disabling fast render, smooth fps and render regions

[ThisNekoGuy]

@KaiAF The issue seems so mainly stem from Fast Render and Render Regions

Fast Render is what causes objects to be visible through other objects and Render Regions is what causes the weird world-disappearing issue (I couldn't tell much of a difference between Smooth FPS being on or off?):

Render Regions.png (filesize was too large for Github)

Loading with a custom texture pack (https://napplab.com - though, the pack was x1024 but I'm still not sure that's appropriate given my hardware) caused it to freeze for a long while upon loading into the server before the game decided to be responsive again (with pretty bad performance). In fact, it took so long, that I actually got booted out of the server on one attempt due to inactivity: