Fix the bug where sometimes shapes occupy the same space as other

shapes.

This is game breaking and gets in the way of testing and developing
other features...

src/bin/tetris/main.rs

@@ -39,10 +39,10 @@ fn main() {
             ),
         )
         .add_systems(
-            OnEnter(DebuggingState::On), toggle_visuals
+            OnEnter(DebuggingState::On), toggle_art
         )
         .add_systems(
-            OnExit(DebuggingState::On), toggle_visuals
+            OnExit(DebuggingState::On), toggle_art
         )
         .add_systems(
             Update,
@@ -88,6 +88,7 @@ fn main() {
                 damage_over_time.run_if(on_timer(Duration::from_secs(5))),
                 check_level_goal.run_if(resource_changed::<Score>),
                 check_level_fail.run_if(any_component_removed::<ShapeBlock>),
+                toggle_art.run_if(any_component_added::<Art>),
             ),
         )
         // UI systems
@@ -396,37 +397,30 @@ fn init_tetris(
         },
         material_o: materials.add(ColorMaterial {
             color: YELLOW.into(),
-            texture: Some(server.load("tetris/shape_block.png")),
             ..default()
         }),
         material_t: materials.add(ColorMaterial {
             color: PURPLE.into(),
-            texture: Some(server.load("tetris/shape_block.png")),
             ..default()
         }),
         material_l: materials.add(ColorMaterial {
             color: ORANGE.into(),
-            texture: Some(server.load("tetris/shape_block.png")),
             ..default()
         }),
         material_j: materials.add(ColorMaterial {
             color: BLUE.into(),
-            texture: Some(server.load("tetris/shape_block.png")),
             ..default()
         }),
         material_s: materials.add(ColorMaterial {
             color: LIME.into(),
-            texture: Some(server.load("tetris/shape_block.png")),
             ..default()
         }),
         material_z: materials.add(ColorMaterial {
             color: RED.into(),
-            texture: Some(server.load("tetris/shape_block.png")),
             ..default()
         }),
         material_i: materials.add(ColorMaterial {
             color: AQUA.into(),
-            texture: Some(server.load("tetris/shape_block.png")),
             ..default()
         }),
     });
@@ -438,7 +432,6 @@ fn init_tetris(
                 Mesh2d(mesh.clone()),
                 MeshMaterial2d(materials.add(ColorMaterial {
                     color: BLACK.into(),
-                    texture: Some(server.load("tetris/bg_block.png")),
                     ..default()
                 })),
                 Art {
@@ -471,7 +464,6 @@ fn init_battler(
     {
         let mat = materials.add(ColorMaterial {
             color: BLUE.into(),
-            texture: Some(server.load("tetris/placeholder_protagonist.png")),
             ..default()
         });
         let mesh = meshes.add(Ellipse::new(SCALE, SCALE * 2.0));
@@ -494,7 +486,6 @@ fn init_battler(
     {
         let mat = materials.add(ColorMaterial {
             color: RED.into(),
-            texture: Some(server.load("tetris/placeholder_enemy.png")),
             ..default()
         });
         let art = Art {
@@ -1492,8 +1483,9 @@ fn check_level_fail(
     });
 }
 
-fn toggle_visuals(
+fn toggle_art(
     state: Res<State<DebuggingState>>,
+    // TODO: Correctness: Query for added or changed <Art> entities
     query: Query<(&MeshMaterial2d<ColorMaterial>, &Art)>,
     mut color_materials: ResMut<Assets<ColorMaterial>>,
 ) {