[Merged by Bors] - can get the settings of a plugin from the app

crates/bevy_app/src/app.rs

@@ -68,6 +68,7 @@ pub struct App {
  /// A container of [`Stage`]s set to be run in a linear order.
  pub schedule: Schedule,
  sub_apps: HashMap<AppLabelId, SubApp>,
+ plugin_registry: Vec<Box<dyn Plugin>>,
 }
 
 impl Debug for App {
@@ -131,6 +132,7 @@ impl App {
  schedule: Default::default(),
  runner: Box::new(run_once),
  sub_apps: HashMap::default(),
+ plugin_registry: Vec::default(),
  }
  }
 
@@ -825,11 +827,58 @@ impl App {
  where
  T: Plugin,
  {
+ self.add_boxed_plugin(Box::new(plugin))
+ }
+
+ /// Boxed variant of `add_plugin`, can be used from a [`PluginGroup`]
+ pub(crate) fn add_boxed_plugin(&mut self, plugin: Box<dyn Plugin>) -> &mut Self {
  debug!("added plugin: {}", plugin.name());
  plugin.build(self);
+ self.plugin_registry.push(plugin);
  self
  }
 
+ /// Checks if a [`Plugin`] has already been added.
+ ///
+ /// This can be used by plugins to check if a plugin dependency they have has already been
+ /// added.
+ pub fn is_plugin_added<T>(&self) -> bool
+ where
+ T: Plugin,
+ {
+ self.plugin_registry
+ .iter()
+ .find(|p| p.downcast_ref::<T>().is_some())
+ .is_some()
+ }
+
+ /// Returns the plugin of a given type that have been added.
+ ///
+ /// This can be used by plugins to get the settings of already added plugins.
+ ///
+ /// ```rust
+ /// # use bevy_app::prelude::*;
+ /// # #[derive(Default)]
+ /// # struct ImagePlugin {
+ /// # default_sampler: bool,
+ /// # }
+ /// # impl Plugin for ImagePlugin {
+ /// # fn build(&self, app: &mut App) {}
+ /// # }
+ /// # let mut app = App::new();
+ /// # app.add_plugin(ImagePlugin::default());
+ /// let default_sampler = app.get_added_plugins::<ImagePlugin>()[0].default_sampler;
+ /// ```
+ pub fn get_added_plugins<T>(&self) -> Vec<&T>
+ where
+ T: Plugin,
+ {
+ self.plugin_registry
+ .iter()
+ .filter_map(|p| p.downcast_ref())
+ .collect()
+ }
+
  /// Adds a group of [`Plugin`]s.
  ///
  /// [`Plugin`]s can be grouped into a set by using a [`PluginGroup`].

crates/bevy_app/src/plugin_group.rs

@@ -155,12 +155,12 @@ impl PluginGroupBuilder {
 
  /// Consumes the [`PluginGroupBuilder`] and [builds](Plugin::build) the contained [`Plugin`]s
  /// in the order specified.
- pub fn finish(self, app: &mut App) {
+ pub fn finish(mut self, app: &mut App) {
  for ty in &self.order {
- if let Some(entry) = self.plugins.get(ty) {
+ if let Some(entry) = self.plugins.remove(ty) {
  if entry.enabled {
  debug!("added plugin: {}", entry.plugin.name());
- entry.plugin.build(app);
+ app.add_boxed_plugin(entry.plugin);
  }
  }
  }