Rotating filter

src/filters.rs

@@ -1,20 +1,48 @@
 use bevy::prelude::*;
 use bevy_rapier2d::prelude::*;
 
-#[derive(Component, Default)]
-pub struct FilterColor(pub Color);
-
 #[derive(Component)]
 pub enum PassThroughFilter {
-	Absorbing,
+	/// Absorbs this color (ignoring alpha)
+	Absorbing(Color),
+	/// Rotates hue by this angle (in degrees)
+	Rotating(f32),
+}
+
+impl PassThroughFilter {
+	pub fn apply(&self, color: Color) -> Color {
+		match self {
+			PassThroughFilter::Absorbing(filter_color) => Vec4::from(color)
+				.mul_add(
+					-Vec4::from(*filter_color) * Vec4::from([1., 1., 1., 0.]),
+					Vec4::from(color),
+				)
+				.into(),
+			PassThroughFilter::Rotating(filter_angle) => {
+				let mut hsla = color.as_hsla_f32();
+				hsla[0] = (hsla[0] + filter_angle) % 360.;
+				Color::hsla(hsla[0], hsla[1], hsla[2], hsla[3])
+			}
+		}
+	}
 }
 
 #[derive(Bundle)]
 pub struct AbsorbingFilter {
-	pub color: FilterColor,
 	#[bundle]
 	pub mesh: ColorMesh2dBundle,
 	pub collider: Collider,
 	pub sensor: Sensor,
-	pub filter_type: PassThroughFilter,
+	pub filter: PassThroughFilter,
+}
+
+#[derive(Bundle)]
+pub struct RotatingFilter {
+	#[bundle]
+	pub sprite: SpriteBundle,
+	pub collider: Collider,
+	pub sensor: Sensor,
+	pub filter: PassThroughFilter,
+	pub velocity: Velocity,
+	pub rigid_body: RigidBody,
 }