1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
use crate::{Extract, RenderApp, RenderStage};
use bevy_app::{App, Plugin};
use bevy_asset::{Asset, AssetEvent, Assets, Handle};
use bevy_derive::{Deref, DerefMut};
use bevy_ecs::{
prelude::*,
system::{StaticSystemParam, SystemParam, SystemParamItem},
};
use bevy_utils::{HashMap, HashSet};
use std::marker::PhantomData;
pub enum PrepareAssetError<E: Send + Sync + 'static> {
RetryNextUpdate(E),
}
pub trait RenderAsset: Asset {
type ExtractedAsset: Send + Sync + 'static;
type PreparedAsset: Send + Sync + 'static;
type Param: SystemParam;
fn extract_asset(&self) -> Self::ExtractedAsset;
fn prepare_asset(
extracted_asset: Self::ExtractedAsset,
param: &mut SystemParamItem<Self::Param>,
) -> Result<Self::PreparedAsset, PrepareAssetError<Self::ExtractedAsset>>;
}
#[derive(Clone, Hash, Debug, Default, PartialEq, Eq, SystemLabel)]
pub enum PrepareAssetLabel {
PreAssetPrepare,
#[default]
AssetPrepare,
PostAssetPrepare,
}
pub struct RenderAssetPlugin<A: RenderAsset> {
prepare_asset_label: PrepareAssetLabel,
phantom: PhantomData<fn() -> A>,
}
impl<A: RenderAsset> RenderAssetPlugin<A> {
pub fn with_prepare_asset_label(prepare_asset_label: PrepareAssetLabel) -> Self {
Self {
prepare_asset_label,
phantom: PhantomData,
}
}
}
impl<A: RenderAsset> Default for RenderAssetPlugin<A> {
fn default() -> Self {
Self {
prepare_asset_label: Default::default(),
phantom: PhantomData,
}
}
}
impl<A: RenderAsset> Plugin for RenderAssetPlugin<A> {
fn build(&self, app: &mut App) {
if let Ok(render_app) = app.get_sub_app_mut(RenderApp) {
let prepare_asset_system = prepare_assets::<A>.label(self.prepare_asset_label.clone());
let prepare_asset_system = match self.prepare_asset_label {
PrepareAssetLabel::PreAssetPrepare => prepare_asset_system,
PrepareAssetLabel::AssetPrepare => {
prepare_asset_system.after(PrepareAssetLabel::PreAssetPrepare)
}
PrepareAssetLabel::PostAssetPrepare => {
prepare_asset_system.after(PrepareAssetLabel::AssetPrepare)
}
};
render_app
.init_resource::<ExtractedAssets<A>>()
.init_resource::<RenderAssets<A>>()
.init_resource::<PrepareNextFrameAssets<A>>()
.add_system_to_stage(RenderStage::Extract, extract_render_asset::<A>)
.add_system_to_stage(RenderStage::Prepare, prepare_asset_system);
}
}
}
#[derive(Resource)]
pub struct ExtractedAssets<A: RenderAsset> {
extracted: Vec<(Handle<A>, A::ExtractedAsset)>,
removed: Vec<Handle<A>>,
}
impl<A: RenderAsset> Default for ExtractedAssets<A> {
fn default() -> Self {
Self {
extracted: Default::default(),
removed: Default::default(),
}
}
}
#[derive(Resource, Deref, DerefMut)]
pub struct RenderAssets<A: RenderAsset>(HashMap<Handle<A>, A::PreparedAsset>);
impl<A: RenderAsset> Default for RenderAssets<A> {
fn default() -> Self {
Self(Default::default())
}
}
fn extract_render_asset<A: RenderAsset>(
mut commands: Commands,
mut events: Extract<EventReader<AssetEvent<A>>>,
assets: Extract<Res<Assets<A>>>,
) {
let mut changed_assets = HashSet::default();
let mut removed = Vec::new();
for event in events.iter() {
match event {
AssetEvent::Created { handle } | AssetEvent::Modified { handle } => {
changed_assets.insert(handle.clone_weak());
}
AssetEvent::Removed { handle } => {
changed_assets.remove(handle);
removed.push(handle.clone_weak());
}
}
}
let mut extracted_assets = Vec::new();
for handle in changed_assets.drain() {
if let Some(asset) = assets.get(&handle) {
extracted_assets.push((handle, asset.extract_asset()));
}
}
commands.insert_resource(ExtractedAssets {
extracted: extracted_assets,
removed,
});
}
#[derive(Resource)]
pub struct PrepareNextFrameAssets<A: RenderAsset> {
assets: Vec<(Handle<A>, A::ExtractedAsset)>,
}
impl<A: RenderAsset> Default for PrepareNextFrameAssets<A> {
fn default() -> Self {
Self {
assets: Default::default(),
}
}
}
fn prepare_assets<R: RenderAsset>(
mut extracted_assets: ResMut<ExtractedAssets<R>>,
mut render_assets: ResMut<RenderAssets<R>>,
mut prepare_next_frame: ResMut<PrepareNextFrameAssets<R>>,
param: StaticSystemParam<<R as RenderAsset>::Param>,
) {
let mut param = param.into_inner();
let queued_assets = std::mem::take(&mut prepare_next_frame.assets);
for (handle, extracted_asset) in queued_assets {
match R::prepare_asset(extracted_asset, &mut param) {
Ok(prepared_asset) => {
render_assets.insert(handle, prepared_asset);
}
Err(PrepareAssetError::RetryNextUpdate(extracted_asset)) => {
prepare_next_frame.assets.push((handle, extracted_asset));
}
}
}
for removed in std::mem::take(&mut extracted_assets.removed) {
render_assets.remove(&removed);
}
for (handle, extracted_asset) in std::mem::take(&mut extracted_assets.extracted) {
match R::prepare_asset(extracted_asset, &mut param) {
Ok(prepared_asset) => {
render_assets.insert(handle, prepared_asset);
}
Err(PrepareAssetError::RetryNextUpdate(extracted_asset)) => {
prepare_next_frame.assets.push((handle, extracted_asset));
}
}
}
}