basic pipe displacement implemented

src/base_game.rs

@@ -1,3 +1,5 @@
+use bevy::platform::hash::RandomState;
+
 use super::*;
 
 /// A good starting place for creating a game building on top of the base Bevy app
@@ -37,7 +39,8 @@ impl Plugin for BaseGamePlugin {
         .add_plugins(DebuggingPlugin)
         .add_plugins(MeshPickingPlugin)
         .add_plugins(LoadingPlugin)
-        .add_plugins(BaseUiPlugin);
+        .add_plugins(BaseUiPlugin)
+        .init_resource::<Rand>();
 
         match self.game_type {
             GameType::Two => app.add_systems(Startup, create_camera_2d),
@@ -76,3 +79,6 @@ pub fn create_camera_2d(mut commands: Commands) {
     info!("Spawning 2d camera");
     commands.spawn((Camera2d, Camera { ..default() }));
 }
+
+#[derive(Default, Resource)]
+pub struct Rand(pub RandomState);

src/bin/flappy/main.rs

@@ -1,6 +1,7 @@
 // Bevy basically forces "complex types" with Querys
 #![allow(clippy::type_complexity)]
 
+use std::hash::BuildHasher;
 use games::physics2d::*;
 use games::*;
 
@@ -14,8 +15,8 @@ fn main() {
             Physics2dPlugin,
         ))
         .insert_resource(Gravity(Vec2::NEG_Y * 9.8 * 100.0))
-        .init_resource::<PipeComponents>()
-        .init_resource::<GroundComponents>()
+        .init_resource::<PipeAssets>()
+        .init_resource::<GroundAssets>()
         .init_resource::<Score>()
         .init_resource::<RewindFrames>()
         .init_resource::<Flaps>()
@@ -250,7 +251,7 @@ fn update_batch_position(
 fn populate_ground(
     trigger: Trigger<OnAdd, Ground>,
     grounds: Query<&Ground>,
-    ground_assets: Res<GroundComponents>,
+    ground_assets: Res<GroundAssets>,
     mut commands: Commands,
 ) {
     let Ground(idx) = grounds.get(trigger.target()).unwrap();
@@ -269,13 +270,31 @@ fn populate_ground(
 /// Otherwise this just spawns in the center of the batch.
 fn populate_pipe(
     trigger: Trigger<OnAdd, Pipe>,
-    pipes: Query<&Pipe>,
-    pipe_assets: Res<PipeComponents>,
+    pipes: Query<(&Pipe, &Batch)>,
+    pipe_assets: Res<PipeAssets>,
     mut commands: Commands,
+    rand: Res<Rand>
 ) {
-    let pipe_t = match pipes.get(trigger.target()).unwrap() {
-        Pipe::Top => Transform::from_xyz(0.0, 200.0, -1.0).with_scale(Vec3::splat(100.0)),
-        Pipe::Bottom => Transform::from_xyz(0.0, -200.0, -1.0).with_scale(Vec3::splat(100.0)),
+    let pipe_t = {
+        let (pipe, Batch(id)) = pipes.get(trigger.target()).unwrap();
+
+        let offset = {
+            let val = rand.0.hash_one(id);
+
+            let option = val % 3;
+
+            match option {
+                0 => 100.0,
+                1 => 0.0,
+                2 => -100.0,
+                _ => panic!("Can only pick 1 of 3 pipe offsets"),
+            }
+        };
+
+        match pipe {
+            Pipe::Top => Transform::from_xyz(0.0, 200.0 + offset, -1.0).with_scale(Vec3::splat(100.0)),
+            Pipe::Bottom => Transform::from_xyz(0.0, -100.0 + offset, -1.0).with_scale(Vec3::splat(100.0)),
+        }
     };
     commands.entity(trigger.target()).insert((
         pipe_t,
@@ -301,13 +320,13 @@ fn populate_hitbox(trigger: Trigger<OnAdd, Hitbox>, mut commands: Commands) {
 }
 
 #[derive(Resource, Default)]
-struct GroundComponents {
+struct GroundAssets {
     material: MeshMaterial2d<ColorMaterial>,
     mesh: Mesh2d,
 }
 
 #[derive(Resource, Default)]
-struct PipeComponents {
+struct PipeAssets {
     material: MeshMaterial2d<ColorMaterial>,
     mesh: Mesh2d,
 }
@@ -316,8 +335,8 @@ struct PipeComponents {
 fn init_obstacle_assets(
     mut meshes: ResMut<Assets<Mesh>>,
     mut materials: ResMut<Assets<ColorMaterial>>,
-    mut pipe_assets: ResMut<PipeComponents>,
-    mut ground_assets: ResMut<GroundComponents>,
+    mut pipe_assets: ResMut<PipeAssets>,
+    mut ground_assets: ResMut<GroundAssets>,
     server: Res<AssetServer>,
 ) {
     pipe_assets.material = MeshMaterial2d(materials.add(ColorMaterial {