[Merged by Bors] - Move texture sample out of branch in prepare_normal

[DGriffin91]

Objective

This fixes #5127

Solution

• Moved texture sample out of branch in prepare_normal().

[Elabajaba]

Fixes the load_gltf example without breaking the array texture example.

LGTM

[alice-i-cecile]

Fixed this for me too!

[alice-i-cecile]

@DGriffin91 can you use either "fixes" or "closes" in the PR description? These are magic words that will cause the issue to get linked properly :)

[IceSentry]

Works for me too!

[alice-i-cecile]

bors r+

[bors]

Pull request successfully merged into main.

Build succeeded:

• build-and-install-on-iOS
• build-android
• build (nightly, ubuntu-latest)
• build (stable, macos-latest)
• build (stable, ubuntu-latest)
• build (stable, windows-latest)
• build-wasm (nightly, ubuntu-latest)
• build-wasm (stable, ubuntu-latest)
• check-compiles
• check-doc
• check-missing-examples-in-docs
• check-unused-dependencies
• ci
• markdownlint
• miri
• run-examples
• run-examples-on-wasm
• run-examples-on-windows

[superdump]

EDIT: Ha! I spoke too soon. Griffin pointed out that both branches sample the texture. Ok. This is fine.

Just noting that this is the ‘wrong’ fix. This will now always sample the texture regardless of whether it needs to or not. The uniform control flow (i.e. branching logic based on values in a uniform) can be evaluated before executing the shader for the 2x2 pixel quad (which is how rasterisation works in order to calculate gradients to identify an appropriate mip level). This means that how things were before, if the uniform flags value meant that the true case didn’t happen, then the texture would not be sampled for any of the fragments being shaded.

The right fix for now is to remove the function parameters for the flags, remove the argument at call sites, and go back to using material.flags, directly referring to the uniform binding variable.