From e5994a4e55a66a6682c02d41706dc1b611435291 Mon Sep 17 00:00:00 2001
From: Sludge <96552222+SludgePhD@users.noreply.github.com>
Date: Sun, 25 Feb 2024 23:34:05 +0100
Subject: [PATCH] Early-exit bloom node if `intensity == 0.0` (#12113)

# Objective

- The bloom effect is currently somewhat costly (in terms of GPU time
used), due to using fragment shaders for down- and upscaling (compute
shaders generally perform better for such tasks).
- Additionally, one might have a `BloomSettings` on a camera whose
`intensity` is only occasionally set to a non-zero value (eg. in outside
areas or areas with bright lighting). Currently, the cost of the bloom
shader is always incurred as long as the `BloomSettings` exists.

## Solution

- Bail out of the bloom render node when `intensity == 0.0`, making the
effect free as long as it is turned all the way down.
---
 crates/bevy_core_pipeline/src/bloom/mod.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/crates/bevy_core_pipeline/src/bloom/mod.rs b/crates/bevy_core_pipeline/src/bloom/mod.rs
index c76ea78934..2896e86e1e 100644
--- a/crates/bevy_core_pipeline/src/bloom/mod.rs
+++ b/crates/bevy_core_pipeline/src/bloom/mod.rs
@@ -129,6 +129,10 @@ impl ViewNode for BloomNode {
         ): QueryItem<Self::ViewQuery>,
         world: &World,
     ) -> Result<(), NodeRunError> {
+        if bloom_settings.intensity == 0.0 {
+            return Ok(());
+        }
+
         let downsampling_pipeline_res = world.resource::<BloomDownsamplingPipeline>();
         let pipeline_cache = world.resource::<PipelineCache>();
         let uniforms = world.resource::<ComponentUniforms<BloomUniforms>>();