zoom with bevy_picking

Cargo.toml

@@ -84,6 +84,9 @@ android_logger = "0.14"
 [profile.dev]
 opt-level = 1
 
+[profile.release]
+debug = true
+
 # Enable a large amount of optimization in the dev profile for dependencies.
 [profile.dev.package."*"]
 opt-level = 3

src/camera.rs

@@ -7,9 +7,9 @@ use crate::ui;
 pub struct Plugin;
 impl bevy::prelude::Plugin for Plugin {
     fn build(&self, app: &mut App) {
-        app.add_systems(Startup, setup)
+        app.add_systems(Startup, setup);
             // .add_systems(Update, move_cam)
-            .init_resource::<Pointers>();
+            // .init_resource::<Pointers>();
     }
 }
 

src/lib.rs

@@ -10,7 +10,7 @@ pub fn main() {
     App::new()
         .add_plugins((
             DefaultPlugins,
-            WorldInspectorPlugin::default(),
+            // WorldInspectorPlugin::default(),
             camera::Plugin,
             map::Plugin,
             ui::Plugin,

src/ui.rs

@@ -1,13 +1,14 @@
 use std::collections::BTreeMap;
 
-use bevy::{math::VectorSpace, picking::pointer::PointerId, prelude::*, utils::HashMap};
+use bevy::{input::mouse::MouseWheel, math::{NormedVectorSpace, VectorSpace}, picking::{focus::HoverMap, pointer::PointerId}, prelude::*, utils::HashMap, window::PrimaryWindow};
 
 use crate::map::{self, MapMarker};
 
 pub struct Plugin;
 impl bevy::prelude::Plugin for Plugin {
     fn build(&self, app: &mut App) {
-        app.add_systems(Startup, setup);
+        app.add_systems(Startup, setup)
+            .add_systems(Update, zoom_with_scroll);
     }
 }
 
@@ -58,13 +59,38 @@ fn setup(
                 let mut ptrs = ptrs.get_mut(event.target).unwrap();
                 
                 let old_midpoint = ptrs.0.values().fold(Vec2::ZERO, |acc, pos| acc + (pos/ptrs.0.len() as f32));
+                let old_d_to_midpoint = ptrs.0.values().fold(0., |acc, pos| acc + (old_midpoint-pos).norm());
                 ptrs.0.insert(event.pointer_id, event.pointer_location.position);
                 let new_midpoint = ptrs.0.values().fold(Vec2::ZERO, |acc, pos| acc + (pos/ptrs.0.len() as f32));
+                let new_d_to_midpoint = ptrs.0.values().fold(0., |acc, pos| acc + (new_midpoint-pos).norm());
 
+                // move camera
                 cam.translation.x -= (new_midpoint.x - old_midpoint.x)*cam.scale.x;
                 cam.translation.y += (new_midpoint.y - old_midpoint.y)*cam.scale.y;
+            
+                if ptrs.0.len() > 1 {
+                    cam.scale *= old_d_to_midpoint/new_d_to_midpoint;
+                }
             }
         }
     );
     // Spawn all ui elements as children of this one
 }
+
+fn zoom_with_scroll(
+    mut cam: Query<&mut Transform, With<Camera2d>>,
+    mut ev_scroll: EventReader<MouseWheel>,
+    hover_map: Res<HoverMap>,
+    window: Query<&Window, With<PrimaryWindow>>,
+    map_ui_id: Query<Entity, With<MapUIComponent>>
+) {
+    let map_ui_id = map_ui_id.single();
+    if hover_map.get(&PointerId::Mouse).and_then(|hovered_ids| hovered_ids.get(&map_ui_id)).is_some() {
+        let window = window.single();
+        let mut cam = cam.single_mut();
+        for ev in ev_scroll.read() {
+            let scale = (cam.scale.x-(ev.y*0.1/window.width().min(window.height()))).clamp(0.0001, 2./window.width().min(window.height()));
+            cam.scale = Vec3::new(scale, scale, scale);
+        }
+    }
+}