1 files changed, 69 insertions, 9 deletions

diff --git a/src/sim/sim_manager/utils.rs b/src/sim/sim_manager/utils.rs
index 13d7891..413e709 100644
--- a/src/sim/sim_manager/utils.rs
+++ b/src/sim/sim_manager/utils.rs
@@ -2,16 +2,10 @@ use glam::IVec2;
 
 use crate::{
     content::materials::MaterialId,
-    sim::{entity::EntityId, sim_manager::SimManager},
+    sim::{cell::Cell, entity::EntityId, sim_manager::SimManager},
 };
 
-pub fn write_entity_to_world(
-    sim: &mut SimManager,
-    entity_id: EntityId,
-    // make sure these cells will be simulated
-    seqno: u64,
-    // (entity_x, entity_y, cell_x, cell_y)
-) -> Vec<(u8, u8, i32, i32)> {
+fn write_entity_to_world(sim: &mut SimManager, entity_id: EntityId) -> Vec<(u8, u8, i32, i32)> {
     let mut cells_written: Vec<(u8, u8, i32, i32)> = Vec::new();
     if let Some(entity) = sim.entities.get(&entity_id)
         && let Some(cells) = &entity.data.cells
@@ -57,7 +51,7 @@ pub fn write_entity_to_world(
                         continue;
                     }
 
-                    cell.match_parity(seqno);
+                    cell.match_parity(sim.cell_manager.seqno);
 
                     // TODO: OPTIMIZE!!
                     sim.cell_manager
@@ -69,3 +63,69 @@ pub fn write_entity_to_world(
     }
     cells_written
 }
+
+pub fn write_entities_to_world(
+    sim: &mut SimManager,
+    // (entity_x, entity_y, cell_x, cell_y)
+) -> Vec<(EntityId, Vec<(u8, u8, i32, i32)>)> {
+    // TODO optimize
+    let entity_ids: Vec<EntityId> = sim.entities.keys().copied().collect();
+    let mut cells_written_by_entity: Vec<(EntityId, Vec<(u8, u8, i32, i32)>)> = Vec::new();
+
+    for entity_id in entity_ids {
+        let cells_written = write_entity_to_world(sim, entity_id);
+        cells_written_by_entity.push((entity_id, cells_written));
+    }
+
+    cells_written_by_entity
+}
+
+// TODO optimize
+pub fn read_back_entities_from_world(
+    sim: &mut SimManager,
+    cells_written_by_entity: Vec<(EntityId, Vec<(u8, u8, i32, i32)>)>,
+) {
+    for (entity_id, cells_written) in cells_written_by_entity {
+        if let Some(entity) = sim.entities.get_mut(&entity_id) {
+            let entity_cells = entity.data.cells.as_mut().unwrap();
+            let mut should_update_entity = false;
+
+            for (lx, ly, x, y) in cells_written {
+                // update the entity
+                // TODO optimize
+                let new_local_cell = sim.cell_manager.get_cell_from_game_position(x, y).unwrap();
+                if !new_local_cell.entity_integrated() {
+                    // this means that the entity changed in some way, so we should recompute its shape
+                    // TODO wait N frames to debounce this
+                    should_update_entity = true;
+                }
+                // we do this unconditionally because it's cheaper than checking if it actually needs to be updated
+                // and because we don't have a good way to track changes to cell state
+                entity_cells
+                    .set_cell_at_local_position(IVec2::new(lx as i32, ly as i32), new_local_cell);
+
+                // update the world
+                // TODO optimize
+                sim.cell_manager
+                    .set_cell_from_game_position(x, y, Cell::void(), false);
+            }
+
+            if should_update_entity {
+                if let Some(new_collider) = entity.compute_collider() {
+                    sim.rb_manager
+                        .physics_manager
+                        .world
+                        .remove_collider(entity.data.collider_h.unwrap());
+
+                    let new_handle = sim
+                        .rb_manager
+                        .physics_manager
+                        .world
+                        .insert_collider(new_collider, Some(entity.data.rb_h.unwrap()));
+
+                    entity.data.collider_h = Some(new_handle);
+                }
+            }
+        }
+    }
+}