From d6664b9b5a9a3aab500b547e4d7448a8bc4ad416 Mon Sep 17 00:00:00 2001
From: Kai Stevenson <kai@kaistevenson.com>
Date: Sun, 23 Aug 2026 01:07:07 -0700
Subject: allow entity damage

---
 src/sim/entity/mod.rs | 56 ++++++++++++++++++++++++++-------------------------
 1 file changed, 29 insertions(+), 27 deletions(-)

(limited to 'src/sim/entity')

diff --git a/src/sim/entity/mod.rs b/src/sim/entity/mod.rs
index d8a03e0..3a3fb1d 100644
--- a/src/sim/entity/mod.rs
+++ b/src/sim/entity/mod.rs
@@ -13,6 +13,13 @@ use crate::{
     },
 };
 
+fn mass_from_cells(cells: &[Cell]) -> f32 {
+    cells
+        .iter()
+        .fold(0, |acc, cur| acc + cur.material.def().density) as f32
+        * MASS_SCALING
+}
+
 pub struct EntityCells {
     pub size: IVec2,
     pub cells: Vec<Cell>,
@@ -43,13 +50,7 @@ impl Marchable for EntityCells {
 }
 
 pub trait EntityBehaviour {
-    fn update(
-        &mut self,
-        _update_ctx: &mut EntityUpdateCtx,
-        _ctx: &mut SimCtx,
-        _delta_time: f32,
-    ) {
-    }
+    fn update(&mut self, _update_ctx: &mut EntityUpdateCtx, _ctx: &mut SimCtx, _delta_time: f32) {}
     fn physics_update(
         &mut self,
         _update_ctx: &mut EntityUpdateCtx,
@@ -76,14 +77,8 @@ impl EntityDef {
             .translation(position / CELLS_TO_METRES)
             .build();
 
-        let mass = cells
-            .cells
-            .iter()
-            .fold(0, |acc, cur| acc + cur.material.def().density) as f32
-            * MASS_SCALING;
-
         let collider = RbManager::convex_hull_collider_from_marchable(&cells, None)
-            .mass(mass)
+            .mass(mass_from_cells(&cells.cells))
             .build();
 
         EntityDef {
@@ -130,19 +125,18 @@ impl<'a> EntityUpdateCtx<'a> {
 
 impl EntityData {
     pub fn transform(&self, ctx: &SimCtx) -> Option<(Vec2, (f32, f32))> {
-        self.rb_h
-            .and_then(|rb_h| {
-                ctx.rb_manager
-                    .physics_manager
-                    .rigid_body_set
-                    .get(rb_h)
-                    .map(|rb| {
-                        (
-                            rb.translation() * CELLS_TO_METRES,
-                            (rb.rotation().cos(), rb.rotation().sin()),
-                        )
-                    })
-            })
+        self.rb_h.and_then(|rb_h| {
+            ctx.rb_manager
+                .physics_manager
+                .rigid_body_set
+                .get(rb_h)
+                .map(|rb| {
+                    (
+                        rb.translation() * CELLS_TO_METRES,
+                        (rb.rotation().cos(), rb.rotation().sin()),
+                    )
+                })
+        })
     }
 }
 
@@ -174,6 +168,14 @@ impl Entity {
         None
     }
 
+    pub fn compute_collider(&self) -> Option<Collider> {
+        self.data.cells.as_ref().map(|cells| {
+            RbManager::convex_hull_collider_from_marchable(cells, None)
+                .mass(mass_from_cells(&cells.cells))
+                .build()
+        })
+    }
+
     pub fn new(
         id: u32,
         rb_h: Option<RigidBodyHandle>,
-- 
cgit v1.3.1