Forward rendering seems broken

[JMS55]

Bevy version

72f096c

Relevant system information

2024-12-06T04:20:17.216608Z  INFO bevy_diagnostic::system_information_diagnostics_plugin::internal: SystemInfo { os: "Windows 11 Home", kernel: "22631", cpu: "AMD Ryzen 7 5800X 8-Core Processor", core_count: "8", memory: "15.9 GiB" }
2024-12-06T04:20:17.720519Z  INFO bevy_render::renderer: AdapterInfo { name: "NVIDIA GeForce RTX 3080", vendor: 4318, device: 8710, device_type: DiscreteGpu, driver: "NVIDIA", driver_info: "560.94", backend: Vulkan }

What you did

Run the deferred_rendering example

What went wrong

Forward rendering seems broken (forward + prepass is fine)

• POM seems broken on the cube
• Normal maps seem to be missing from the flight helmet

[pcwalton]

Bisecting this. The lack of POM on the cube repros even as far back as Sep 13. So that at least isn't a recent regression.

[DGriffin91]

Note: Lack of parallax on the cube in forward + prepass was in the initial creation of this scene. Forward + prepass has never supported parallax mapping. (Not to be confused with the current issue with parallax on the cube in forward on current main)

[JMS55]

Yes, but it's also broken in pure forward now (there's some weird ghosting 🙃)

[pcwalton]

The culprit for the loss of normal mapping is the retained render world, #15320.

Note that deferred was broken at the time that commit landed (due to PCSS) and wasn't fixed until #15656, which is ddd4b4d. So you'll want to git cherry-pick ddd4b4daf8bb3df1dac0fd5f453269ff4bd4f99a if you check out that commit.

[hukasu]

one of the issues being described here is the shadow being retained when changing from Deferred or Forward + Prepass into Forward, right?

taken using 85eceb0

[hukasu]

things got worse on 7aeb1c5

Deferred

Deferred -> Forward

Forward -> Deferred

Deferred -> Forward + Prepass

Forward + Prepass -> Forward

Forward -> Deferred

[hukasu]

git bisect done
dda97880c48ff39c3a77ff2eb398c34b382cb771 is the first bad commit

[pcwalton]

The root of the problem is that we add prepasses to the render world views but don't remove them. #17565 fixes that but can't be merged yet because it exposes other bugs.