Account for near clipping plane in sprite backend (#293)

* Account for near clipping plane in sprite backend * Correctly subtract z transform * Improve docs * Update changelog * formatting --------- Co-authored-by: Aevyrie <[email protected]>
aevyrie · Feb 24, 2024 · f1a64e2 · f1a64e2
1 parent ec249c3
commit f1a64e2
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,5 +1,6 @@
 # UNRELEASED
 
+- Fixed: sprite picking depth is now consistent with other picking backends.
 - Fixed: entities with identical depth could be dropped due to the use of a BTreeMap to sort
   entities by depth. This has been changed to use a sorted Vec, to allow entities with the same
   depth to coexist.

diff --git a/backends/bevy_picking_sprite/src/lib.rs b/backends/bevy_picking_sprite/src/lib.rs
@@ -35,7 +35,7 @@ impl Plugin for SpriteBackend {
 /// Checks if any sprite entities are under each pointer
 pub fn sprite_picking(
     pointers: Query<(&PointerId, &PointerLocation)>,
-    cameras: Query<(Entity, &Camera, &GlobalTransform)>,
+    cameras: Query<(Entity, &Camera, &GlobalTransform, &OrthographicProjection)>,
     primary_window: Query<Entity, With<PrimaryWindow>>,
     images: Res<Assets<Image>>,
     texture_atlas: Res<Assets<TextureAtlas>>,
@@ -63,10 +63,10 @@ pub fn sprite_picking(
         pointer_location.location().map(|loc| (pointer, loc))
     }) {
         let mut blocked = false;
-        let Some((cam_entity, camera, cam_transform)) = cameras
+        let Some((cam_entity, camera, cam_transform, cam_ortho)) = cameras
             .iter()
-            .filter(|(_, camera, _)| camera.is_active)
-            .find(|(_, camera, _)| {
+            .filter(|(_, camera, _, _)| camera.is_active)
+            .find(|(_, camera, _, _)| {
                 camera
                     .target
                     .normalize(Some(primary_window.single()))
@@ -123,10 +123,10 @@ pub fn sprite_picking(
                 blocked =
                     is_cursor_in_sprite && pickable.map(|p| p.should_block_lower) != Some(false);
 
-                is_cursor_in_sprite.then_some((
-                    entity,
-                    HitData::new(cam_entity, sprite_transform.translation().z, None, None),
-                ))
+                // HitData requires a depth as calculated from the camera's near clipping plane
+                let depth = -cam_ortho.near - sprite_transform.translation().z;
+
+                is_cursor_in_sprite.then_some((entity, HitData::new(cam_entity, depth, None, None)))
             })
             .collect();
 

diff --git a/crates/bevy_picking_core/src/backend.rs b/crates/bevy_picking_core/src/backend.rs
@@ -85,16 +85,16 @@ impl PointerHits {
     }
 }
 
-/// Holds data from a successful pointer hit test.
-///
-/// `depth` only needs to be self-consistent with other [`PointerHits`]s using the same
-/// [`RenderTarget`](bevy_render::camera::RenderTarget).
+/// Holds data from a successful pointer hit test. See [`HitData::depth`] for important details.
 #[derive(Clone, Debug, PartialEq, Reflect)]
 pub struct HitData {
     /// The camera entity used to detect this hit. Useful when you need to find the ray that was
     /// casted for this hit when using a raycasting backend.
     pub camera: Entity,
-    /// The distance from the pointer to the entity into the screen, or depth.
+    /// `depth` only needs to be self-consistent with other [`PointerHits`]s using the same
+    /// [`RenderTarget`](bevy_render::camera::RenderTarget). However, it is recommended to use the
+    /// distance from the pointer to the hit, measured from the near plane of the camera, to the
+    /// point, in world space.
     pub depth: f32,
     /// The position of the intersection in the world, if the data is available from the backend.
     pub position: Option<Vec3>,