Second camera ToneMapping and/or RenderLayers impacts first camera

[lucidBrot]

Bevy version

[[package]]
name = "bevy"
version = "0.15.1"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "bb2a21c9f3306676077a88700bb8f354be779cf9caba9c21e94da9e696751af4"
dependencies = [
 "bevy_dylib",
 "bevy_internal",
]

[Optional] Relevant system information

If you cannot get Bevy to build or run on your machine, please include:

• Rust version:

  • cargo 1.83.0 (5ffbef321 2024-10-29)
  • and cargo 1.85.0-nightly (769f622e1 2024-12-14)

• OS: Debian Trixie,

uname -a
Linux nevermore 6.11.9-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.11.9-1 (2024-11-17) x86_64 GNU/Linux

If your bug is rendering-related, copy the adapter info that appears when you run Bevy.

2025-01-24T23:44:49.673613Z  INFO bevy_render::renderer: AdapterInfo { name: "Intel(R) Graphics (MTL)", vendor: 32902, device: 32069, device_type: IntegratedGpu, driver: "Intel open-source Mesa driver", driver_info: "Mesa 24.2.8-1", backend: Vulkan }

What you did

1. Paste the code from the 2d Bloom example and run it. It works.
2. Add a second camera by copy-pasting the first camera.
3. Add two separate Marker components to make sure the system expecting a single camera will not make problems. Use the marker there for the query.
4. Set the first Camera to order: 1 and the second Camera to order: 2 , so the second camera should be drawn over the first camera. Add clear_color: ClearColorConfig::None to the second Camera.
5. At this point, everything is still working.
6. Specify for the second camera: RenderLayers::from_layers(&[1,]) to make the overlay camera render different entities. There are none of those, of course, but that does not matter.
7. Run it and observe that the image looks muted.

Here is what I changed:

commit 6bbbc56c72a7cbab1b411c4cef7aa814ba1f3789
Author: LucidBrot <eric@mink.li>
Date:   Sat Jan 25 00:44:10 2025 +0100

    This is muted

diff --git a/src/main.rs b/src/main.rs
index 13f687f..d890632 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -8,6 +8,12 @@ use bevy::{
     },
     prelude::*,
 };
+use bevy::render::view::visibility::RenderLayers;
+
+#[derive(Component)]
+struct CameraMarker1{}
+#[derive(Component)]
+struct CameraMarker2{}
 
 fn main() {
     App::new()
@@ -25,12 +31,29 @@ fn setup(
 ) {
     commands.spawn((
         Camera2d,
+        CameraMarker1{},
+        Camera {
+            hdr: true, // 1. HDR is required for bloom
+            order: 1,
+            ..default()
+        },
+        Tonemapping::TonyMcMapface, // 2. Using a tonemapper that desaturates to white is recommended
+        Bloom::default(),           // 3. Enable bloom for the camera
+        RenderLayers::from_layers(&[0,]),
+    ));
+
+    commands.spawn((
+        Camera2d,
+        CameraMarker2{},
         Camera {
             hdr: true, // 1. HDR is required for bloom
+            order: 2,
+            clear_color: ClearColorConfig::None,
             ..default()
         },
         Tonemapping::TonyMcMapface, // 2. Using a tonemapper that desaturates to white is recommended
         Bloom::default(),           // 3. Enable bloom for the camera
+        RenderLayers::from_layers(&[1,]),
     ));
 
     // Sprite
@@ -72,7 +95,7 @@ fn setup(
 // ------------------------------------------------------------------------------------------------
 
 fn update_bloom_settings(
-    camera: Single<(Entity, Option<&mut Bloom>), With<Camera>>,
+    camera: Single<(Entity, Option<&mut Bloom>), With<CameraMarker1>>,
     mut text: Single<&mut Text>,
     mut commands: Commands,
     keycode: Res<ButtonInput<KeyCode>>,

Interestingly, the issue is dependent on both

• having the Tonemapping present in the second camera
• using RenderLayers 1, instead of the default 0

What went wrong

Expected:

Actual:

I am not certain whether this might be intended behavior somehow, but it is certainly not what I expected. My use-case will be to show a Menu overlaid over the Game Entities. Both cameras are supposed to apply the same effects. Muting the background could be nice, but I'd want to explicitly do that, not have it as a side effect of having an unused camera.

Additional information

Issues I've found that may or may not have anything to do with this at all:

• Set scissor on upscale to match camera viewport #14287
• Tonemapping affects other cameras in split screen #14389

  • what were you expecting?
    Tonemapping to look the same on each camera
  • what actually happened?
    The tonemapping looks more intense on other cameras, appears like it's multiplying the effect due to it not being constrained to the camera's viewport.

• SMAA looks extreme in split screen on non-top level viewports #14197

  I believe this is caused by the effect writing outside the camera's viewport causing a multiplying effect with the camera's layered on top of each other.

• [0.13] An orthographic 2d Camera on top of a 3d Perspective Camera - Potential bug with Camera2d ClearColorConfig #12121 (Also is using Bloom, but otherwise seems different to me)

bloom1.zip