From 2ee69807b11630a2564aa4c05153958cb5dec7d4 Mon Sep 17 00:00:00 2001
From: UkoeHB <37489173+UkoeHB@users.noreply.github.com>
Date: Mon, 8 Apr 2024 12:00:09 -0500
Subject: [PATCH] Fix potential out-of-bounds access in pbr_functions.wgsl
 (#12585)

# Objective

- Fix a potential out-of-bounds access in the `pbr_functions.wgsl`
shader.

## Solution

- Correctly compute the `GpuLights::directional_lights` array length.

## Comments

I think this solves this comment in the code, but need someone to test
it:
```rust
//NOTE: When running bevy on Adreno GPU chipsets in WebGL, any value above 1 will result in a crash
// when loading the wgsl "pbr_functions.wgsl" in the function apply_fog.
```
---
 crates/bevy_pbr/src/render/light.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/crates/bevy_pbr/src/render/light.rs b/crates/bevy_pbr/src/render/light.rs
index e616ee250c..bb0c7853dd 100644
--- a/crates/bevy_pbr/src/render/light.rs
+++ b/crates/bevy_pbr/src/render/light.rs
@@ -991,7 +991,8 @@ pub fn prepare_lights(
                 cluster_factors_zw.y,
             ),
             cluster_dimensions: clusters.dimensions.extend(n_clusters),
-            n_directional_lights: directional_lights.iter().len() as u32,
+            n_directional_lights: directional_lights.iter().len().min(MAX_DIRECTIONAL_LIGHTS)
+                as u32,
             // spotlight shadow maps are stored in the directional light array, starting at num_directional_cascades_enabled.
             // the spot lights themselves start in the light array at point_light_count. so to go from light
             // index to shadow map index, we need to subtract point light count and add directional shadowmap count.