ammo system

* heads have abilities
* health and ammo shows in ui

src/backpack/backpack_ui.rs

@@ -1,4 +1,4 @@
-use super::{BackbackSwapEvent, Backpack, BackpackHead};
+use super::{BackbackSwapEvent, Backpack, UiHeadState};
 use crate::{GameState, heads_ui::HeadsImages, loading_assets::UIAssets, sounds::PlaySound};
 use bevy::prelude::*;
 
@@ -29,7 +29,7 @@ struct HeadDamage(pub usize);
 
 #[derive(Resource, Default, Debug)]
 struct BackpackUiState {
-    heads: [Option<BackpackHead>; 5],
+    heads: [Option<UiHeadState>; 5],
     scroll: usize,
     count: usize,
     current_slot: usize,
@@ -316,7 +316,7 @@ fn sync(backpack: &Res<Backpack>, state: &mut ResMut<BackpackUiState>) {
 
     for i in 0..HEAD_SLOTS {
         if let Some(head) = backpack.heads.get(i + state.scroll) {
-            state.heads[i] = Some(*head);
+            state.heads[i] = Some(UiHeadState::from(*head));
         } else {
             state.heads[i] = None;
         }