bevy/crates/bevy_sprite/Cargo.toml
Rob Parrett bdb063497d
Use radsort for Transparent2d PhaseItem sorting (#9882)
# Objective

Fix a performance regression in the "[bevy vs
pixi](https://github.com/SUPERCILEX/bevy-vs-pixi)" benchmark.

This benchmark seems to have a slightly pathological distribution of `z`
values -- Sprites are spawned with a random `z` value with a child
sprite at `f32::EPSILON` relative to the parent.

See discussion here:
https://github.com/bevyengine/bevy/issues/8100#issuecomment-1726978633

## Solution

Use `radsort` for sorting `Transparent2d` `PhaseItem`s.

Use random `z` values in bevymark to stress the phase sort. Add an
`--ordered-z` option to `bevymark` that uses the old behavior.

## Benchmarks

mac m1 max

| benchmark | fps before | fps after | diff |
| - | - | - | - |
| bevymark --waves 120 --per-wave 1000 --random-z | 42.16 | 47.06 | 🟩
+11.6% |
| bevymark --waves 120 --per-wave 1000 | 52.50 | 52.29 | 🟥 -0.4% |
| bevymark --waves 120 --per-wave 1000 --mode mesh2d --random-z | 9.64 |
10.24 | 🟩 +6.2% |
| bevymark --waves 120 --per-wave 1000 --mode mesh2d | 15.83 | 15.59 | 🟥
-1.5% |
| bevy-vs-pixi | 39.71 | 59.88 | 🟩 +50.1% |

## Discussion

It's possible that `TransparentUi` should also change. We could probably
use `slice::sort_unstable_by_key` with the current sort key though, as
its items are always sorted and unique. I'd prefer to follow up later to
look into that.

Here's a survey of sorts used by other `PhaseItem`s

#### slice::sort_by_key
`Transparent2d`, `TransparentUi`

#### radsort
`Opaque3d`, `AlphaMask3d`, `Transparent3d`, `Opaque3dPrepass`,
`AlphaMask3dPrepass`, `Shadow`

I also tried `slice::sort_unstable_by_key` with a compound sort key
including `Entity`, but it didn't seem as promising and I didn't test it
as thoroughly.

---------

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Robert Swain <robert.swain@gmail.com>
2023-09-21 17:53:20 +00:00

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TOML

[package]
name = "bevy_sprite"
version = "0.12.0-dev"
edition = "2021"
description = "Provides sprite functionality for Bevy Engine"
homepage = "https://bevyengine.org"
repository = "https://github.com/bevyengine/bevy"
license = "MIT OR Apache-2.0"
keywords = ["bevy"]
[dependencies]
# bevy
bevy_app = { path = "../bevy_app", version = "0.12.0-dev" }
bevy_asset = { path = "../bevy_asset", version = "0.12.0-dev" }
bevy_core_pipeline = { path = "../bevy_core_pipeline", version = "0.12.0-dev" }
bevy_ecs = { path = "../bevy_ecs", version = "0.12.0-dev" }
bevy_log = { path = "../bevy_log", version = "0.12.0-dev" }
bevy_math = { path = "../bevy_math", version = "0.12.0-dev" }
bevy_reflect = { path = "../bevy_reflect", version = "0.12.0-dev", features = [
"bevy",
] }
bevy_render = { path = "../bevy_render", version = "0.12.0-dev" }
bevy_transform = { path = "../bevy_transform", version = "0.12.0-dev" }
bevy_utils = { path = "../bevy_utils", version = "0.12.0-dev" }
bevy_derive = { path = "../bevy_derive", version = "0.12.0-dev" }
# other
bytemuck = { version = "1.5", features = ["derive"] }
fixedbitset = "0.4"
guillotiere = "0.6.0"
thiserror = "1.0"
rectangle-pack = "0.4"
bitflags = "2.3"
radsort = "0.1"