1 files changed, 23 insertions, 10 deletions
diff --git a/engine-ecs/src/system.rs b/engine-ecs/src/system.rs
index 38e480d..5395b14 100644
--- a/engine-ecs/src/system.rs
+++ b/engine-ecs/src/system.rs
@@ -3,6 +3,7 @@ use std::fmt::Debug;
 use seq_macro::seq;
 
 use crate::error::Error;
+use crate::event::Emitted as EmittedEvent;
 use crate::uid::Uid;
 use crate::{Component, World};
 
@@ -31,7 +32,7 @@ macro_rules! impl_system {
             impl<'world, Func, Ret, #(TParam~I,)*> System<'world, fn(#(TParam~I,)*) -> Ret>
                 for Func
             where
-                Func: Fn(#(TParam~I,)*) -> Ret + 'static,
+                Func: Fn(#(TParam~I,)*) -> Ret + Copy + 'static,
                 Ret: ReturnValue,
                 #(TParam~I: Param<'world, Input = ()>,)*
             {
@@ -41,16 +42,23 @@ macro_rules! impl_system {
                 {
                     #![allow(unused)]
 
+                    crate::util::const_assert!(
+                        size_of::<Func>() == 0,
+                        "System function is not zero-sized (not function pointer)"
+                    );
+
                     let type_erased = TypeErased {
-                        run: Box::new(move |world, metadata| {
+                        run: |world, metadata, _| {
                             // SAFETY: The caller of TypeErased::run ensures the lifetime
                             // is correct
                             let world = unsafe { &*std::ptr::from_ref(world) };
 
-                            self(#({
+                            let func = unsafe { std::mem::zeroed::<Func>() };
+
+                            func(#({
                                 TParam~I::new(world, &metadata)
                             },)*).into_result()
-                        }),
+                        },
                         name: std::any::type_name::<Self>()
                     };
 
@@ -74,8 +82,8 @@ pub trait Into<'world, Impl>
 
 pub struct TypeErased
 {
-    run: Box<TypeErasedRunFn>,
-    name: &'static str,
+    pub run: TypeErasedRunFn,
+    pub name: &'static str,
 }
 
 impl TypeErased
@@ -84,9 +92,14 @@ impl TypeErased
     ///
     /// # Safety
     /// `world_data` must live at least as long as the [`World`] the system belongs to.
-    pub unsafe fn run(&self, world: &World, metadata: Metadata) -> Result<(), Error>
+    pub unsafe fn run(
+        &self,
+        world: &World,
+        metadata: Metadata,
+        evt: Option<EmittedEvent<'_>>,
+    ) -> Result<(), Error>
     {
-        (self.run)(world, metadata)
+        (self.run)(world, metadata, evt)
     }
 
     pub fn name(&self) -> &'static str
@@ -153,5 +166,5 @@ pub(crate) struct SystemComponent
     pub(crate) system: TypeErased,
 }
 
-/// Function in [`TypeErased`] used to run the system.
-type TypeErasedRunFn = dyn Fn(&World, Metadata) -> Result<(), Error>;
+type TypeErasedRunFn =
+    fn(&World, Metadata, Option<EmittedEvent<'_>>) -> Result<(), Error>;