1 files changed, 52 insertions, 2 deletions
diff --git a/src/sim/cell_sim/sim.rs b/src/sim/cell_sim/sim.rs
index fd9b6c9..0f02a23 100644
--- a/src/sim/cell_sim/sim.rs
+++ b/src/sim/cell_sim/sim.rs
@@ -5,10 +5,14 @@ use rand::{Rng, SeedableRng, rngs::SmallRng};
 use rayon::iter::{IntoParallelRefIterator, ParallelIterator};
 
 use crate::{
-    config::CHUNK_SIZE,
+    config::{CELLS_IN_CHUNK, CHUNK_SIZE},
     sim::{
-        cell::{cell::Cell, materials::MaterialDef},
+        cell::{
+            cell::Cell,
+            materials::{MaterialDef, MaterialId},
+        },
         cell_sim::{chunk::Chunk, world::World},
+        rb_sim::{RbSimManager, rb_entity::RbEntity},
     },
 };
 
@@ -177,6 +181,52 @@ const NEIGHBORHOOD_OFFSETS: [(i32, i32); 9] = [
     (1, 1),
 ];
 
+pub fn write_rb_entity_to_world(
+    world: &mut World,
+    rb_sim_manager: &RbSimManager,
+    rb_entity_id: u32,
+    next_seqno: u64,
+) {
+    if let Some(rb_entity) = rb_sim_manager.rb_entities.get(&rb_entity_id)
+        && let Some((rb_x, rb_y, cos, sin)) = rb_sim_manager.get_rb_entity_transform(rb_entity_id)
+    {
+        let half_size = CHUNK_SIZE as f32 / 2.0;
+        // half-extent of the rotated grid's axis-aligned bounding box, plus a cell of margin
+        let radius = half_size * (cos.abs() + sin.abs()) + 1.0;
+
+        let world_xl = (rb_x - radius).floor() as i32;
+        let world_xu = (rb_x + radius).ceil() as i32;
+        let world_yl = (rb_y - radius).floor() as i32;
+        let world_yu = (rb_y + radius).ceil() as i32;
+
+        for world_x in world_xl..=world_xu {
+            for world_y in world_yl..=world_yu {
+                // same as shader
+                let d = (world_x as f32 + 0.5 - rb_x, world_y as f32 + 0.5 - rb_y);
+                let q = (d.0.floor() + 0.5, d.1.floor() + 0.5);
+                let (lx, ly) = (
+                    (q.0 * cos + q.1 * sin + half_size).floor() as i32,
+                    (-q.0 * sin + q.1 * cos + half_size).floor() as i32,
+                );
+
+                if lx < 0 || ly < 0 || lx >= CHUNK_SIZE || ly >= CHUNK_SIZE {
+                    continue;
+                }
+
+                let mut cell = rb_entity.get_cell_at_local_position(lx as u8, ly as u8);
+                if cell.material == MaterialId::Void {
+                    continue;
+                }
+
+                cell.match_parity(next_seqno);
+
+                // TODO: OPTIMIZE!!
+                world.set_cell_from_game_position(world_x, world_y, cell, false);
+            }
+        }
+    }
+}
+
 pub fn sim_tick(world: &mut World, seqno: u64, use_threading: bool) {
     puffin::profile_function!();