initial commit

Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "bevy_laser"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+bevy = "0.12.1"
+rand = "0.8.5"

src/main.rs

@@ -0,0 +1,80 @@
+use bevy::{
+    prelude::*,
+};
+
+#[derive(Component,Debug)]
+struct Pos(Vec2);
+#[derive(Component,Debug)]
+struct Ray(Vec2);
+#[derive(Component,Debug)]
+struct Col(Color);
+#[derive(Component,Debug)]
+struct Size(f32);
+
+fn main() {
+    App::new()
+        .add_plugins(DefaultPlugins)
+	.add_systems(Startup, setup)
+	.add_systems(Update, (animate, rand_color, gizmos))
+	.run()
+}
+
+fn setup(
+    mut commands: Commands,
+) {
+    commands.spawn(Camera2dBundle {
+	transform: Transform::from_xyz(250.0, 0.0, 0.0),
+	..default()
+    });
+    
+    commands.spawn((
+	Pos(Vec2::new(0.0, 0.0)),
+	Ray(Vec2::new(100.0, 5.0)),
+	Col(Color::rgba(1.0, 0.0, 1.0, 1.0)),
+	Size(10.0)
+    ));
+
+    commands.spawn((
+	Pos(Vec2::new(0.0, 0.0)),
+	Ray(Vec2::new(200.0, 1.0)),
+	Col(Color::rgba(1.0, 1.0, 0.0, 1.0)),
+	Size(20.0)
+    ));
+
+}
+
+fn animate(
+    time: Res<Time>,
+    mut query: Query<(&mut Pos, &Ray)>
+) {
+    let t = time.elapsed_seconds();
+    for (mut pos, ray) in &mut query {
+	pos.0.x = (ray.0.y*t).cos() * ray.0.x;
+	pos.0.y = (ray.0.y*t).sin() * ray.0.x;
+    }
+}
+
+fn rand_color(
+    time: Res<Time>,
+    mut query: Query<&mut Col>
+) {
+    let t = time.delta_seconds();
+    for mut col in &mut query {
+	if let Color::Rgba{ ref mut red, .. } = col.0 {
+	    *red += t;
+	    if *red > 1.0 {
+		*red = 0.0;
+	    }
+	}
+    }
+}
+
+fn gizmos(
+    mut gizmos: Gizmos,
+    query: Query<(&Pos,&Col,&Size)>
+) {
+    for (Pos(pos), Col(color), Size(size)) in &query {
+	gizmos.circle_2d(*pos, *size, *color);
+    }
+}
+