feat: zoom through objects

examples/zoom_through.rs

@@ -0,0 +1,47 @@
+//! A minimal example demonstrating zooming through objects.
+
+use bevy::prelude::*;
+use bevy_editor_cam::prelude::*;
+
+fn main() {
+    App::new()
+        .add_plugins((
+            DefaultPlugins,
+            bevy_mod_picking::DefaultPickingPlugins,
+            DefaultEditorCamPlugins,
+        ))
+        .add_systems(Startup, (setup_camera, setup_scene))
+        .run()
+}
+
+fn setup_camera(mut commands: Commands) {
+    commands.spawn((
+        Camera3dBundle::default(),
+        EditorCam {
+            minimum_distance: Some(1.5), // If an object is 1.5m away from the camera, begin zooming through it.
+            ..default()
+        },
+    ));
+}
+
+//
+// --- The below code is not important for the example ---
+//
+
+fn setup_scene(
+    mut commands: Commands,
+    mut meshes: ResMut<Assets<Mesh>>,
+    mut materials: ResMut<Assets<StandardMaterial>>,
+) {
+    let material = materials.add(Color::rgba(0.1, 0.1, 0.9, 0.5));
+    let mesh = meshes.add(Cuboid::from_size(Vec3::new(3.0, 3.0, 0.25)));
+
+    for i in 1..5 {
+        commands.spawn(PbrBundle {
+            mesh: mesh.clone(),
+            material: material.clone(),
+            transform: Transform::from_xyz(0.0, 0.0, -5.0 * i as f32),
+            ..default()
+        });
+    }
+}

src/controller/component.rs

@@ -64,6 +64,9 @@ pub struct EditorCam {
     pub perspective: PerspectiveSettings,
     /// Settings used when the camera has an orthographic [`Projection`].
     pub orthographic: OrthographicSettings,
+    /// How close can the camera get to object before zooming through it. None
+    /// disables zooming through objects.
+    pub minimum_distance: Option<f64>,
     /// Managed by the camera controller, though you may want to change this when spawning or
     /// manually moving the camera.
     ///
@@ -89,6 +92,7 @@ impl Default for EditorCam {
             orthographic: Default::default(),
             enabled_motion: Default::default(),
             current_motion: Default::default(),
+            minimum_distance: Default::default(),
             last_anchor_depth: -2.0,
         }
     }
@@ -220,6 +224,20 @@ impl EditorCam {
             return;
         }
         let anchor = self.maybe_update_anchor(anchor);
+
+        // Extend the anchor if a minimum distance for zooming is set
+        let anchor = if let Some(minimum_distance) = self.minimum_distance {
+            if anchor.length() > minimum_distance {
+                anchor
+            } else if let Some(norm_anchor) = anchor.try_normalize() {
+                norm_anchor * minimum_distance
+            } else {
+                anchor
+            }
+        } else {
+            anchor
+        };
+
         // Inherit current camera velocity
         let zoom_inputs = match self.current_motion {
             CurrentMotion::Stationary | CurrentMotion::Momentum { .. } => InputQueue::default(),