vel and pos

component-macro/src/lib.rs

@@ -12,10 +12,10 @@ fn impl_derive_macro(ast: &syn::DeriveInput) -> TokenStream {
     let name = &ast.ident;
     let gen = quote! {
         impl Component for #name {
-            fn inner_type_id(&self) -> TypeId {
-                TypeId::of::<Self>()
+            fn inner_type_id(&self) -> std::any::TypeId {
+                std::any::TypeId::of::<Self>()
             }
-            fn as_any(&mut self) -> &mut dyn Any {
+            fn as_any(&mut self) -> &mut dyn std::any::Any {
                 self
             }
         }

src/engine.rs

@@ -1,7 +1,7 @@
 use std::any::{Any, TypeId};
 use std::collections::HashSet;
 use std::rc::Rc;
-use std::time::Duration;
+use std::time::{Duration, Instant};
 
 pub use sdl2::keyboard::Keycode;
 
@@ -212,7 +212,7 @@ impl<'context, 'game> Context<'context, 'game> {
 
 pub trait System {
     fn on_add(&self, _ctx: &mut Context) {}
-    fn on_update(&self, _ctx: &mut Context) -> Result<(), Error> {
+    fn on_update(&self, _ctx: &mut Context, _delta: f64) -> Result<(), Error> {
         Ok(())
     }
 }
@@ -266,6 +266,7 @@ impl<'game> Game<'game> {
     }
 
     pub fn run(&mut self) {
+        let mut time_before = Instant::now();
         'running: loop {
             for event in self.event_pump.poll_iter() {
                 match event {
@@ -285,8 +286,11 @@ impl<'game> Game<'game> {
             }
             self.canvas.set_draw_color(Color::RGB(60, 180, 180));
             self.canvas.clear();
+            let now = Instant::now();
+            let delta = (now - time_before).as_nanos() as f64 / 1_000_000_000.0;
+            time_before = now;
             for system in self.systems.clone() {
-                let Err(err) = system.on_update(&mut self.context()) else {
+                let Err(err) = system.on_update(&mut self.context(), delta) else {
                     continue;
                 };
                 println!("error occcurred updating system: {err}");

src/main.rs

@@ -1,52 +1,82 @@
 #![allow(dead_code)]
 
-use component_macro::Component;
-use engine::QuwiQuwi;
-use engine::{Sprite, System};
-use std::any::{Any, TypeId};
-use std::rc::Rc;
 mod engine;
 
+use component_macro::Component;
 use engine::Component;
+use engine::QuwiQuwi;
+use engine::System;
+use std::rc::Rc;
 
 #[derive(Component)]
-struct Player {
-    sprite: Sprite,
+struct Sprite {
+    sprite: engine::Sprite,
 }
 
 #[derive(Component)]
-struct Position(i32, i32);
+struct Position(f64, f64);
 
+#[derive(Clone, Component)]
+struct Velocity(f64, f64);
+
+struct VelocitySystem;
+impl System for VelocitySystem {
+    fn on_update(&self, ctx: &mut engine::Context, delta: f64) -> Result<(), engine::Error> {
+        for id in engine::Quwi::<(Velocity, Position)>::new().run(&ctx) {
+            let vel = ctx.entity_component::<Velocity>(id).clone();
+            let Position(x, y) = ctx.entity_component::<Position>(id);
+            *x += vel.0 * delta;
+            *y += vel.1 * delta;
+        }
+        Ok(())
+    }
+}
+
+#[derive(Component)]
 struct Gravity;
 
-impl System for Gravity {
-    fn on_update(&self, ctx: &mut engine::Context) -> Result<(), engine::Error> {
-        for id in ctx.entities_with_component::<Position>() {
-            let Position(_, y) = ctx.entity_component::<Position>(id);
-            *y += 1;
+struct GravitySystem;
+impl System for GravitySystem {
+    fn on_update(&self, ctx: &mut engine::Context, delta: f64) -> Result<(), engine::Error> {
+        for id in engine::Quwi::<(Gravity, Velocity)>::new().run(&ctx) {
+            let Velocity(_, y) = ctx.entity_component::<Velocity>(id);
+            *y = if *y < 200.0 { *y + 100.0 * delta } else { *y };
         }
         Ok(())
     }
 }
 
 struct SpriteRenderer;
-
 impl System for SpriteRenderer {
-    fn on_update(&self, ctx: &mut engine::Context) -> Result<(), engine::Error> {
-        for id in engine::Quwi::<(Player, Position)>::new().run(&ctx) {
+    fn on_update(&self, ctx: &mut engine::Context, _delta: f64) -> Result<(), engine::Error> {
+        for id in engine::Quwi::<(Sprite, Position)>::new().run(&ctx) {
             let &mut Position(x, y) = ctx.entity_component::<Position>(id);
-            let sprite = ctx.entity_component::<Player>(id).sprite;
+            let sprite = ctx.entity_component::<Sprite>(id).sprite;
 
-            ctx.draw_sprite(sprite, x, y)?;
+            ctx.draw_sprite(sprite, x as i32, y as i32)?;
         }
         Ok(())
     }
 }
 
+#[derive(Component)]
 struct PlayerMovement;
 
-impl System for PlayerMovement {
-    fn on_update(&self, _ctx: &mut engine::Context) -> Result<(), engine::Error> {
+struct PlayerMovementSystem;
+impl System for PlayerMovementSystem {
+    fn on_update(&self, ctx: &mut engine::Context, _delta: f64) -> Result<(), engine::Error> {
+        for id in engine::Quwi::<(PlayerMovement, Velocity)>::new().run(&ctx) {
+            let d_down = ctx.key_pressed(engine::Keycode::D);
+            let a_down = ctx.key_pressed(engine::Keycode::A);
+            let Velocity(x, _) = ctx.entity_component::<Velocity>(id);
+            *x = if d_down && !a_down {
+                100.0
+            } else if !d_down && a_down {
+                -100.0
+            } else {
+                0.0
+            };
+        }
         Ok(())
     }
 }
@@ -55,9 +85,17 @@ fn main() {
     let mut game = engine::Game::new().unwrap();
 
     let mut context = game.context();
+    context.add_system(Rc::new(VelocitySystem));
     context.add_system(Rc::new(SpriteRenderer));
-    context.add_system(Rc::new(Gravity));
+    context.add_system(Rc::new(GravitySystem));
+    context.add_system(Rc::new(PlayerMovementSystem));
     let sprite = context.load_sprite("textures/player.png").unwrap();
-    context.spawn(vec![Box::new(Player { sprite }), Box::new(Position(16, 0))]);
+    context.spawn(vec![
+        Box::new(Sprite { sprite }),
+        Box::new(Position(16.0, 140.0)),
+        Box::new(Velocity(0.0, -150.0)),
+        Box::new(Gravity),
+        Box::new(PlayerMovement),
+    ]);
     game.run();
 }