rust 😭

src/engine.rs

@@ -69,6 +69,60 @@ where
     currently_pressed_keys: &'context HashSet<Keycode>,
 }
 
+pub struct Quwi<T>(std::marker::PhantomData<T>);
+
+impl<T> Quwi<T> {
+    pub fn new() -> Self {
+        Self(std::marker::PhantomData)
+    }
+}
+
+pub trait QuwiQuwi {
+    fn run(&self, context: &Context) -> Vec<u64>;
+}
+
+impl<T0> QuwiQuwi for Quwi<T0>
+where
+    T0: 'static + Component,
+{
+    fn run(&self, context: &Context) -> Vec<u64> {
+        context.entities_with_component::<T0>()
+    }
+}
+
+impl<T0, T1> QuwiQuwi for Quwi<(T0, T1)>
+where
+    T0: 'static + Component,
+    T1: 'static + Component,
+{
+    fn run(&self, context: &Context) -> Vec<u64> {
+        let vs0 = context.entities_with_component::<T0>();
+        let vs1 = context.entities_with_component::<T1>();
+        vs0.into_iter()
+            .filter(|v0| vs1.iter().find(|v1| *v0 == **v1).is_some())
+            .collect()
+    }
+}
+
+impl<T0, T1, T2> QuwiQuwi for Quwi<(T0, T1, T2)>
+where
+    T0: 'static + Component,
+    T1: 'static + Component,
+    T2: 'static + Component,
+{
+    fn run(&self, context: &Context) -> Vec<u64> {
+        let vs0 = context.entities_with_component::<T0>();
+        let vs1 = context.entities_with_component::<T1>();
+        let vs2 = context.entities_with_component::<T2>();
+        vs0.into_iter()
+            .filter(|v0| {
+                vs1.iter().find(|v1| *v0 == **v1).is_some()
+                    && vs2.iter().find(|v2| *v0 == **v2).is_some()
+            })
+            .collect()
+    }
+}
+
 impl<'context, 'game> Context<'context, 'game> {
     pub fn entities_with_component<T: 'static + Component>(&self) -> Vec<u64> {
         let entity_type_id = TypeId::of::<T>();
@@ -117,12 +171,11 @@ impl<'context, 'game> Context<'context, 'game> {
         let texture: Texture<'game> = unsafe { (*self.texture_creator).load_texture(&path)? };
         let id = *self.id_counter;
         *self.id_counter += 1;
-
         self.textures.push((id, texture));
         Ok(Sprite(id))
     }
 
-    pub fn draw_sprite(&mut self, sprite: &Sprite, x: i32, y: i32) -> Result<(), Error> {
+    pub fn draw_sprite(&mut self, sprite: Sprite, x: i32, y: i32) -> Result<(), Error> {
         let texture = self
             .textures
             .iter()
@@ -254,6 +307,7 @@ impl<'game> Game<'game> {
             entities: &mut self.entities,
             systems: &mut self.systems,
             textures: &mut self.textures,
+            currently_pressed_keys: &mut self.currently_pressed_keys,
         }
     }
 }

src/main.rs

@@ -1,6 +1,7 @@
 #![allow(dead_code)]
 
 use component_macro::Component;
+use engine::QuwiQuwi;
 use engine::{Sprite, System};
 use std::any::{Any, TypeId};
 use std::rc::Rc;
@@ -28,15 +29,15 @@ impl System for Gravity {
     }
 }
 
-struct PlayerRenderer;
+struct SpriteRenderer;
 
-impl System for PlayerRenderer {
+impl System for SpriteRenderer {
     fn on_update(&self, ctx: &mut engine::Context) -> Result<(), engine::Error> {
-        for id in ctx.entities_with_component::<Player>() {
+        for id in engine::Quwi::<(Player, Position)>::new().run(&ctx) {
             let &mut Position(x, y) = ctx.entity_component::<Position>(id);
-            let player = ctx.entity_component::<Player>(id);
+            let sprite = ctx.entity_component::<Player>(id).sprite;
 
-            ctx.draw_sprite(&player.sprite, x, y)?;
+            ctx.draw_sprite(sprite, x, y)?;
         }
         Ok(())
     }
@@ -45,14 +46,16 @@ impl System for PlayerRenderer {
 struct PlayerMovement;
 
 impl System for PlayerMovement {
-    fn on_update(&self, _ctx: &mut engine::Context) -> Result<(), engine::Error> {}
+    fn on_update(&self, _ctx: &mut engine::Context) -> Result<(), engine::Error> {
+        Ok(())
+    }
 }
 
 fn main() {
     let mut game = engine::Game::new().unwrap();
 
     let mut context = game.context();
-    context.add_system(Rc::new(PlayerRenderer));
+    context.add_system(Rc::new(SpriteRenderer));
     context.add_system(Rc::new(Gravity));
     let sprite = context.load_sprite("textures/player.png").unwrap();
     context.spawn(vec![Box::new(Player { sprite }), Box::new(Position(16, 0))]);