feat: unfinished item drag and drop

src/inventory/ui.rs

@@ -1,25 +1,45 @@
 use std::f32::consts::FRAC_PI_2;
 
-use bevy::prelude::*;
+use bevy::{ecs::component::{ComponentId, ComponentIdFor}, prelude::*};
 
 use crate::{inventory::{ActiveInventory, Inventory, item::Item}, ui::{UiRoot, WindowSize}};
 
 const UI_SLOT_ASSET_PATH: &'static str = "sprites/ui/inventory_slot.png";
 const TEMP_ITEM_PATH: &'static str = "sprites/items/choco_bar.png";
 
-#[derive(Component)]
+#[derive(Component, Reflect)]
 #[require(Node)]
 pub struct UiInventory;
 
-#[derive(Component)]
+#[derive(Component, Reflect)]
 #[require(Node, ImageNode)]
 pub struct UiInventorySlot(UVec2);
 
-#[derive(Component)]
+#[derive(Component, Reflect)]
 #[require(Node, ImageNode)]
 pub struct UiItem(Entity);
 
-fn ui_inventory_bundle(inventory: &Inventory, window_size: &Res<WindowSize>) -> impl Bundle {
+fn on_item_drag_drop(
+    event: On<Pointer<DragDrop>>,
+    ui_item_query: Query<&UiItem>,
+    slot_query: Query<(&UiInventorySlot, Option<&Children>)>,
+) {
+    info!("dragdrop {} {}", event.dropped, event.event_target());
+    let Ok(ui_item) = ui_item_query.get(event.dropped) else {
+        return;
+    };
+    let Ok((slot, _)) = slot_query.get(event.event_target()) else {
+        return;
+    };
+
+    info!("Item {:?} dropped on {:?}", ui_item.0, slot.0);
+}
+
+fn ui_inventory_bundle(
+    inventory: &Inventory,
+    window_size: &Res<WindowSize>,
+    _slot_id: ComponentId,
+) -> impl Bundle {
     let window_ratio = window_size.aspect_ratio();
     let (width, height) = {
         if window_ratio >= 1. {
@@ -41,6 +61,10 @@ fn ui_inventory_bundle(inventory: &Inventory, window_size: &Res<WindowSize>) ->
             grid_auto_rows: vec![GridTrack::percent(100. / inventory.size.y as f32)],
             ..default()
         },
+        Pickable::IGNORE,
+        GlobalZIndex::default(),
+        Observer::new(on_item_drag_drop)
+//            .with_component(slot_id),
     )
 }
 
@@ -60,6 +84,10 @@ fn inventory_slot_bundle(x: u32, y: u32, image: Handle<Image>) -> impl Bundle {
             align_items: AlignItems::Start,
             ..default()
         },
+        Pickable {
+            should_block_lower: true,
+            is_hoverable: true,
+        },
     )
 }
 
@@ -97,6 +125,10 @@ fn ui_item_bundle(item: &Item, item_entity: Entity, image: Handle<Image>) -> imp
         BackgroundColor(Color::hsla(0., 0., 0., 0.5)),
         ui_transform,
         GlobalZIndex(1),
+        Pickable {
+            should_block_lower: false,
+            is_hoverable: true,
+        },
     )
 }
 
@@ -106,6 +138,7 @@ pub fn setup_ui_inventory(
     inventory_query: Query<(&Inventory, Option<&Children>), With<ActiveInventory>>,
     item_query: Query<&Item>,
     root_query: Query<Entity, With<UiRoot>>,
+    slot_id: ComponentIdFor<UiInventorySlot>,
     window_size: Res<WindowSize>,
 ) {
     let Ok(root) = root_query.single() else {
@@ -129,7 +162,7 @@ pub fn setup_ui_inventory(
             }
             None => Vec::new(),
         };
-        let inventory_entity = commands.spawn(ui_inventory_bundle(inventory, &window_size))
+        let inventory_entity = commands.spawn(ui_inventory_bundle(inventory, &window_size, slot_id.get()))
             .with_children(|commands| {
                 for x in 0..inventory.size.x { for y in 0..inventory.size.y {
                     let mut slot_commands = commands.spawn(inventory_slot_bundle(x, y, ui_slot_image.clone()));
@@ -139,7 +172,8 @@ pub fn setup_ui_inventory(
                     }
                 } }
             }).id();
-        commands.entity(root).add_child(inventory_entity);
+        commands.entity(root)
+            .add_child(inventory_entity);
 
         // for simplicity we'll show only first inventory
         break;