From 92dd02d7cc4d9fc930760d26d81edbe2197a3fc0 Mon Sep 17 00:00:00 2001
From: Kai Stevenson <kai@kaistevenson.com>
Date: Tue, 18 Aug 2026 20:20:32 -0700
Subject: marching rigid bodies

---
 src/sim/rb_sim/rb_entity.rs | 28 +++++++++++++++++++++-------
 1 file changed, 21 insertions(+), 7 deletions(-)

(limited to 'src/sim/rb_sim/rb_entity.rs')

diff --git a/src/sim/rb_sim/rb_entity.rs b/src/sim/rb_sim/rb_entity.rs
index 50243bc..08813f6 100644
--- a/src/sim/rb_sim/rb_entity.rs
+++ b/src/sim/rb_sim/rb_entity.rs
@@ -1,24 +1,38 @@
 use rapier2d::prelude;
 
-use crate::{
-    config::{CELLS_IN_CHUNK, CHUNK_SIZE},
-    sim::cell::cell::Cell,
+use crate::sim::{
+    cell::{cell::Cell, materials::MaterialId},
+    lib::marching_squares::Marchable,
 };
 
 pub struct RbEntity {
     pub id: u32,
-    // TODO resizable
-    pub cells: Box<[Cell; CELLS_IN_CHUNK]>,
+    pub width: i32,
+    pub height: i32,
+    pub cells: Vec<Cell>,
     pub rb_parent: prelude::RigidBodyHandle,
 }
 
 impl RbEntity {
     #[inline]
     pub fn get_cell_at_local_position(&self, x: u8, y: u8) -> Cell {
-        self.cells[x as usize + y as usize * CHUNK_SIZE as usize]
+        self.cells[x as usize + y as usize * self.width as usize]
     }
     #[inline]
     pub fn set_cell_at_local_position(&mut self, x: u8, y: u8, cell: Cell) {
-        self.cells[x as usize + y as usize * CHUNK_SIZE as usize] = cell;
+        self.cells[x as usize + y as usize * self.width as usize] = cell;
+    }
+}
+
+impl Marchable for RbEntity {
+    fn occupied(&self, x: i32, y: i32) -> bool {
+        if x < 0 || x >= self.width || y < 0 || y >= self.height {
+            false
+        } else {
+            self.get_cell_at_local_position(x as u8, y as u8).material != MaterialId::Void
+        }
+    }
+    fn size(&self) -> (i32, i32) {
+        (self.width, self.height)
     }
 }
-- 
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