From 88cd679fa7e8159bd53d363f78d82f55ca161b50 Mon Sep 17 00:00:00 2001
From: Elijah Voigt <elijah.caine.mv@gmail.com>
Date: Tue, 9 Sep 2025 22:38:57 -0700
Subject: [PATCH] Parallax 2d (sans wraparound) working

---
 examples/parallax2d.rs | 47 +++++++++++++++++++++++++++++++++++-------
 examples/parallax3d.rs | 17 +++++++--------
 2 files changed, 48 insertions(+), 16 deletions(-)

diff --git a/examples/parallax2d.rs b/examples/parallax2d.rs
index ebf6f01..83e82f1 100644
--- a/examples/parallax2d.rs
+++ b/examples/parallax2d.rs
@@ -4,8 +4,9 @@ fn main() {
     App::new()
         .add_plugins(DefaultPlugins)
         .insert_resource(ClearColor(WHITE.into()))
+        .add_event::<CameraMovement>()
         .add_systems(Startup, setup_2d)
-        .add_systems(Update, move_camera)
+        .add_systems(Update, (move_camera, track_camera_movement, parallax))
         .run();
 }
 
@@ -28,32 +29,64 @@ fn setup_2d(
     commands.spawn((
         Mesh2d(meshes.add(Rectangle::new(100.0, 100.0))),
         MeshMaterial2d(materials.add(Color::from(RED))),
+        Transform::from_xyz(0.0, 0.0, -1.0),
         ParallaxDistance(1.0),
+        children![(Text2d::new("Parallax Distance: 1"), TextColor(BLACK.into()), Transform::from_xyz(150.0, 50.0, 0.0))],
     ));
 
     commands.spawn((
         Mesh2d(meshes.add(Rectangle::new(100.0, 100.0))),
         MeshMaterial2d(materials.add(Color::from(GREEN))),
+        Transform::from_xyz(0.0, 0.0, -5.0),
         ParallaxDistance(5.0),
+        children![(Text2d::new("Parallax Distance: 5"), TextColor(BLACK.into()), Transform::from_xyz(150.0, 0.0, 0.0))],
     ));
 
     commands.spawn((
         Mesh2d(meshes.add(Rectangle::new(100.0, 100.0))),
         MeshMaterial2d(materials.add(Color::from(BLUE))),
+        Transform::from_xyz(0.0, 0.0, -10.0),
         ParallaxDistance(10.0),
+        children![(Text2d::new("Parallax Distance: 10"), TextColor(BLACK.into()), Transform::from_xyz(150.0, -50.0, 0.0))],
     ));
 }
 
 fn move_camera(keys: Res<ButtonInput<KeyCode>>, mut camera: Single<&mut Transform, With<Camera>>) {
-    const SPEED: f32 = 0.1;
+    const SPEED: f32 = 5.0;
     if keys.pressed(KeyCode::ArrowLeft) {
-        camera.translation.z += SPEED;
+        camera.translation.x += SPEED;
     } else if keys.pressed(KeyCode::ArrowRight) {
-        camera.translation.z -= SPEED;
-    } else if keys.pressed(KeyCode::ArrowUp) {
         camera.translation.x -= SPEED;
+    }
+
+    if keys.pressed(KeyCode::ArrowUp) {
+        camera.translation.y -= SPEED;
     } else if keys.pressed(KeyCode::ArrowDown) {
-        camera.translation.x += SPEED;
+        camera.translation.y += SPEED;
     }
-    info!("Position: {:?}", camera.translation);
+}
+
+#[derive(Event)]
+struct CameraMovement(Vec3);
+
+fn track_camera_movement(
+    mut events: EventWriter<CameraMovement>,
+    camera: Query<&Transform, (With<Camera>, Changed<Transform>)>,
+    mut last: Local<Vec3>
+) {
+    camera.iter().for_each(|Transform { translation, .. }| {
+        events.write(CameraMovement(*last - *translation));
+        *last = *translation;
+    });
+}
+
+fn parallax(
+    mut events: EventReader<CameraMovement>,
+    mut query: Query<(&mut Transform, &ParallaxDistance)>,
+) {
+    events.read().for_each(|CameraMovement(v)| {
+        query.iter_mut().for_each(|(mut t, ParallaxDistance(d))| {
+            t.translation -= v / (20.0 / d);
+        });
+    });
 }
diff --git a/examples/parallax3d.rs b/examples/parallax3d.rs
index 5d89593..eeb1109 100644
--- a/examples/parallax3d.rs
+++ b/examples/parallax3d.rs
@@ -17,9 +17,8 @@ fn setup_3d(
     commands.spawn((
         Camera::default(),
         Camera3d::default(),
-        Transform::default().looking_at(Vec3::new(0.0, -1.0, 0.0), Vec3::Y),
         AmbientLight {
-            brightness: 160.0,
+            brightness: 1280.0,
             ..default()
         },
     ));
@@ -30,7 +29,7 @@ fn setup_3d(
             base_color: RED.into(),
             ..Default::default()
         })),
-        Transform::from_xyz(0.0, -10.0, 0.0),
+        Transform::from_xyz(0.0, 0.0, -10.0),
     ));
 
     commands.spawn((
@@ -39,7 +38,7 @@ fn setup_3d(
             base_color: GREEN.into(),
             ..Default::default()
         })),
-        Transform::from_xyz(0.0, -50.0, 0.0),
+        Transform::from_xyz(0.0, 0.0, -50.0),
     ));
 
     commands.spawn((
@@ -48,21 +47,21 @@ fn setup_3d(
             base_color: BLUE.into(),
             ..Default::default()
         })),
-        Transform::from_xyz(0.0, -100.0, 0.0),
+        Transform::from_xyz(0.0, 0.0, -100.0),
     ));
 }
 
 fn move_camera(keys: Res<ButtonInput<KeyCode>>, mut camera: Single<&mut Transform, With<Camera>>) {
     const SPEED: f32 = 0.1;
     if keys.pressed(KeyCode::ArrowLeft) {
-        camera.translation.z += SPEED;
+        camera.translation.x += SPEED;
     } else if keys.pressed(KeyCode::ArrowRight) {
-        camera.translation.z -= SPEED;
+        camera.translation.x -= SPEED;
     }
 
     if keys.pressed(KeyCode::ArrowUp) {
-        camera.translation.x -= SPEED;
+        camera.translation.y -= SPEED;
     } else if keys.pressed(KeyCode::ArrowDown) {
-        camera.translation.x += SPEED;
+        camera.translation.y += SPEED;
     }
 }