Book updates

amethyst_assets/src/prefab/mod.rs

@@ -487,7 +487,7 @@ mod tests {
         world.add_resource(pool.clone());
         world.add_resource(Loader::new(".", pool));
         world.add_resource(Time::default());
-        let mut system = PrefabLoaderSystem::<MyPrefab>::default();
+        let mut system = PrefabLoaderSystem::<MyPrefab>::new(&mut world);
         RunNow::setup(&mut system, &mut world.res);
 
         let prefab = Prefab::new_main(Transform::default());

book/src/concepts/event-channel.md

@@ -173,7 +173,7 @@ and you also need to get read access:
 # }
 ```
 
-Then, in the `System`'s setup method:
+Then, in the `System`'s new method:
 ```rust,edition2018,no_run,noplaypen
 # extern crate amethyst;
 # use amethyst::shrev::{EventChannel, ReaderId};
@@ -183,15 +183,18 @@ Then, in the `System`'s setup method:
 #   A,
 #   B,
 # }
-# struct MySystem { reader: Option<ReaderId<MyEvent>>, }
+# struct MySystem { reader: ReaderId<MyEvent>, }
+#
+# impl MySystem {
+#    pub fn new(world: &mut World) -> Self {
+#        <Self as System<'_>>::SystemData::setup(&mut world.res);
+#        Self {
+#            reader: world.res.fetch_mut::<EventChannel<MyEvent>>().register_reader(),
+#        }
+#
 # impl<'a> amethyst::ecs::System<'a> for MySystem {
 #   type SystemData = ();
 #   fn run(&mut self, _: Self::SystemData) { }
-#   fn setup(&mut self, res: &mut amethyst::ecs::Resources) {
-    // IMPORTANT: You need to setup your system data BEFORE you try to fetch the resource. Especially if you plan use `Default` to create your resource.
-    Self::SystemData::setup(res);
-    self.reader = Some(res.fetch_mut::<EventChannel<MyEvent>>().register_reader());
-#   }
 # }
 
 ```
@@ -207,12 +210,12 @@ Finally, you can read events from your `System`.
 #   B,
 # }
 # struct MySystem {
-#   reader: Option<amethyst::shrev::ReaderId<MyEvent>>,
+#   reader: amethyst::shrev::ReaderId<MyEvent>,
 # }
 # impl<'a> amethyst::ecs::System<'a> for MySystem {
 #   type SystemData = Read<'a, EventChannel<MyEvent>>;
     fn run(&mut self, my_event_channel: Self::SystemData) {
-        for event in my_event_channel.read(self.reader.as_mut().unwrap()) {
+        for event in my_event_channel.read(&mut self.reader) {
             println!("Received an event: {:?}", event);
         }
     }

book/src/concepts/system.md

@@ -540,22 +540,3 @@ impl<'a> System<'a> for MyFirstSystem {
 }
 ```
 
-## The setup method
-
-Systems have a method called setup which is called a single time, before any of the system runs.
-Here is how to use it:
-
-```rust,edition2018,no_run,noplaypen
-# extern crate amethyst;
-# use amethyst::ecs::{System, Resources, SystemData, Entity};
-# struct MySystem { entity: Entity }
-# impl<'a> System<'a> for MySystem {
-#   type SystemData = ();
-#   fn run(&mut self, _: Self::SystemData) { }
-    fn setup(&mut self, res: &mut Resources) {
-        // Ensures that resources that implement `Default` and are present in your `SystemData` are added to `Resources`.
-        Self::SystemData::setup(res);
-        // Do what you want with `Resources` past this point.
-    }
-# }
-```

book/src/testing/test_examples.md

@@ -20,24 +20,26 @@
 # #[derive(Debug)]
 # struct MySystem;
 #
+# impl MySystem {
+#     pub fn new(world: &mut World) -> Self {
+#         <Self as System<'_>>::SystemData::setup(&mut world.res);
+#         world.res.insert(ApplicationResource);
+#         Self
+#     }
+#
 # impl<'s> System<'s> for MySystem {
 #     type SystemData = ReadExpect<'s, ApplicationResource>;
 #
 #     fn run(&mut self, _: Self::SystemData) {}
-#
-#     fn setup(&mut self, res: &mut Resources) {
-#         Self::SystemData::setup(res);
-#         res.insert(ApplicationResource);
-#     }
 # }
 #
 #[derive(Debug)]
 struct MyBundle;
 
 impl<'a, 'b> SystemBundle<'a, 'b> for MyBundle {
-    fn build(self, builder: &mut DispatcherBuilder<'a, 'b>) -> Result<(), Error> {
+    fn build(self, world: &mut World, builder: &mut DispatcherBuilder<'a, 'b>) -> Result<(), Error> {
         // System that adds `ApplicationResource` to the `World`
-        builder.add(MySystem, "my_system", &[]);
+        builder.add(MySystem::new(&mut world), "my_system", &[]);
         Ok(())
     }
 }