Sprite in `bloom_2d` example is not rendered

[rparrett]

Bevy version

main, bisected to #17735

Relevant system information

SystemInfo { os: "macOS 15.3 Sequoia", kernel: "24.3.0", cpu: "Apple M4 Max", core_count: "16", memory: "64.0 GiB" }
AdapterInfo { name: "Apple M4 Max", vendor: 0, device: 0, device_type: IntegratedGpu, driver: "", driver_info: "", backend: Metal }

But this also reproduces in CI in the example report.

What you did

cargo run --example bloom_2d

What went wrong

The bevy logo sprite that should be displayed in the center of the screen is not.

[hukasu]

disabling tonemapping causes the sprite to show

[hukasu]

Screencast_20250210_201711.webm

[Elabajaba]

main_opaque_pass_2d writes to main_texture_sampled and main_texture_a, then main_transparent_pass_2d writes to main_texture_sampled and main_texture_b, but then the first bloom pass takes in main_texture_a.

I don't think we expect to be flipping the main_texture_a/b between the main passes (we don't for 3d, and the flip-flopping is for post-processing so we don't have to allocate new textures for every pass).