add very ugly camera-follows-player effect

src/demo/movement.rs

@@ -62,13 +62,14 @@ impl Default for MovementController {
 
 fn apply_movement(
     _time: Res<Time>,
+    mut camera: Query<&mut Transform, With<Camera>>,
     movement_query: Query<&MovementController, With<Player>>,
-    player_transform_query: Query<&Transform, With<Player>>,
+    player_transform_query: Query<&GlobalTransform, With<Player>>,
     mut players: Query<&mut GridCoords, With<Player>>,
     level_selection: Res<LevelSelection>,
     // level_walls: Res<LevelWalls>,
     level_walls: Res<MultiLevelWalls>,
-) {
+) -> Result {
     let level_selection_iid = match level_selection.as_ref() {
         LevelSelection::Iid(iid) => iid,
         _ => panic!("level should be selected by iid"),
@@ -93,7 +94,7 @@ fn apply_movement(
             } else {
                 // unrecognized intent, log a warning
                 warn!("Unrecognized intent: {:?}", controller.intent);
-                return;
+                return Ok(());
             };
             info!("player old absolute coords: {:?}", player_abs_coords);
             let destination = *player_abs_coords + movement_direction;
@@ -107,12 +108,17 @@ fn apply_movement(
                     player_transform_query.single()
                 );
                 // transform.translation += velocity.extend(0.0) * time.delta_secs();
+                if let Ok(player_transform) = player_transform_query.single() {
+                    let mut camera_transform = camera.single_mut()?;
+                    camera_transform.translation = player_transform.translation();
+                }
             } else {
                 info!("SDENG!");
             }
             level_walls.debug_collisions(level_selection_iid, &player_abs_coords);
         }
     }
+    Ok(())
 }
 
 #[derive(Component, Reflect)]