made paddles move... the tutorial advances

src/main.rs

@@ -1,12 +1,14 @@
 extern crate amethyst;
 
 mod pong;
+mod systems;
 
 use amethyst::prelude::*;
 use amethyst::renderer::{DisplayConfig, DrawFlat2D, Event, Pipeline,
                          RenderBundle, Stage, VirtualKeyCode};
 use amethyst::utils::application_root_dir;
 use amethyst::core::transform::TransformBundle;
+use amethyst::input::InputBundle;
 use crate::pong::Pong;
 
 fn main() -> amethyst::Result<()> {
@@ -17,16 +19,23 @@ fn main() -> amethyst::Result<()> {
     let pipe = Pipeline::build()
     .with_stage(
         Stage::with_backbuffer()
-            .clear_target([0.00196, 0.23726, 0.21765, 1.0], 1.0)
+            .clear_target([0.00196, 0.23726, 0.11765, 1.0], 1.0)
             .with_pass(DrawFlat2D::new()),
     );
 
+    let binding_path = format!(
+        "{}/resources/bindings_config.ron",
+        application_root_dir()
+    );
+
+    let input_bundle = InputBundle::<String, String>::new()
+        .with_bindings_from_file(binding_path)?;
+    
     let game_data = GameDataBuilder::default()
-    .with_bundle(
-      RenderBundle::new(pipe, Some(config))
-        .with_sprite_sheet_processor()
-    )?
-    .with_bundle(TransformBundle::new())?;
+        .with_bundle(RenderBundle::new(pipe, Some(config)).with_sprite_sheet_processor())?
+        .with_bundle(TransformBundle::new())?
+        .with_bundle(input_bundle)?
+        .with(systems::PaddleSystem, "paddle_system", &["input_system"]);
 
     let mut game = Application::new("./", Pong, game_data)?;
     

src/pong.rs

@@ -10,8 +10,8 @@ use amethyst::renderer::{
 
 pub const ARENA_HEIGHT: f32 = 100.0;
 pub const ARENA_WIDTH: f32 = 100.0;
+pub const PADDLE_HEIGHT: f32 = 16.0;
 
-const PADDLE_HEIGHT: f32 = 16.0;
 const PADDLE_WIDTH: f32 = 4.0;
 
 pub struct Pong;
@@ -21,7 +21,7 @@ impl SimpleState for Pong {
         let world = data.world;
         let sprite_sheet_handle = load_sprite_sheet(world);
 
-        world.register::<Paddle>();
+        //world.register::<Paddle>();
         initialise_paddles(world, sprite_sheet_handle);
         initialise_camera(world);
     }

src/systems/mod.rs

@@ -0,0 +1,3 @@
+mod paddle;
+
+pub use self::paddle::PaddleSystem;

src/systems/paddle.rs

@@ -0,0 +1,34 @@
+use amethyst::core::Transform;
+use amethyst::ecs::{Join, Read, ReadStorage, System, WriteStorage};
+use amethyst::input::InputHandler;
+
+// You'll have to mark PADDLE_HEIGHT as public in pong.rs
+use crate::pong::{Paddle, Side, ARENA_HEIGHT, PADDLE_HEIGHT};
+
+pub struct PaddleSystem;
+
+impl<'s> System<'s> for PaddleSystem {
+  type SystemData = (
+    WriteStorage<'s, Transform>,
+    ReadStorage<'s, Paddle>,
+    Read<'s, InputHandler<String, String>>,
+  );
+
+  fn run(&mut self, (mut transforms, paddles, input): Self::SystemData) {
+    for (paddle, transform) in (&paddles, &mut transforms).join() {
+      let movement = match paddle.side {
+        Side::Left => input.axis_value("left_paddle"),
+        Side::Right => input.axis_value("right_paddle"),
+      };
+      if let Some(mv_amount) = movement {
+        let scaled_amount = 1.2 * mv_amount as f32;
+        let paddle_y = transform.translation().y;
+        transform.set_y(
+            (paddle_y + scaled_amount)
+                .min(ARENA_HEIGHT - PADDLE_HEIGHT * 0.5)
+                .max(PADDLE_HEIGHT * 0.5),
+        );
+      }
+    }
+  }
+}