From 3d476186f53d695c340c51dbd3aa14ff4621c520 Mon Sep 17 00:00:00 2001
From: Kai Stevenson <kai@kaistevenson.com>
Date: Sun, 16 Aug 2026 23:52:34 -0700
Subject: trivial placement

---
 src/main.rs | 36 ++++++++++++++++++++++++++++++++----
 1 file changed, 32 insertions(+), 4 deletions(-)

(limited to 'src/main.rs')

diff --git a/src/main.rs b/src/main.rs
index 976a272..ccc5ec5 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -4,6 +4,7 @@ mod renderer;
 mod sim;
 
 use futures::executor;
+use fxhash::FxHashMap;
 use rand::random_range;
 use std::{collections::VecDeque, sync::Arc, time::Instant};
 use winit::{
@@ -23,8 +24,11 @@ use crate::{
     renderer::RendererState,
     sim::{
         cell::{cell::Cell, materials::MaterialId},
-        cell_sim::{sim::sim_tick, world::World},
-        rb_sim::{PhysicsManager, RbSimManager},
+        cell_sim::{
+            sim::{sim_tick, write_rb_entity_to_world},
+            world::World,
+        },
+        rb_sim::RbSimManager,
     },
 };
 
@@ -34,6 +38,7 @@ pub type Result<T> = std::result::Result<T, Error>;
 struct Config {
     brush_radius: f32,
     brush_material: MaterialId,
+    dropper_material: MaterialId,
     use_threading: bool,
 }
 
@@ -102,7 +107,7 @@ impl App {
             && let Some(rbsm) = &mut self.rb_sim_manager
         {
             self.input.trigger_test_1 = false;
-            rbsm.test_spawn_box(lm.0, lm.1);
+            rbsm.test_spawn_box(lm.0, lm.1, self.config.dropper_material);
         }
 
         // --TEST DRAWING--
@@ -125,8 +130,8 @@ impl App {
                         && r > 0.9
                     {
                         let mut cell = Cell::from_material(self.config.brush_material);
+                        cell.match_parity(self.sim_seqno);
                         // ensure we simulate on the first tick
-                        cell.flags = (self.sim_seqno as u8) & 0b1;
                         if let Some(world) = &mut self.world {
                             world.set_cell_from_game_position(
                                 x, y, cell, false, // wake the chunk
@@ -196,6 +201,7 @@ impl Default for App {
                 use_threading: true,
                 brush_radius: 10.0,
                 brush_material: MaterialId::Sand,
+                dropper_material: MaterialId::Sand,
             },
             diagnostics: Diagnostics {
                 fps: 0.0,
@@ -263,6 +269,28 @@ impl ApplicationHandler for App {
                     KeyCode::KeyS => self.input.is_down_pressed = pressed,
                     KeyCode::KeyD => self.input.is_right_pressed = pressed,
                     KeyCode::KeyC => self.world = Some(World::from_default_size()),
+                    KeyCode::KeyV => {
+                        self.rb_sim_manager
+                            .as_mut()
+                            .map(|rbsm| rbsm.rb_entities = FxHashMap::default());
+                    }
+                    KeyCode::KeyP if pressed && !repeat => {
+                        if let Some(rbsm) = self.rb_sim_manager.as_mut() {
+                            for &id in rbsm.rb_entities.keys() {
+                                write_rb_entity_to_world(
+                                    self.world.as_mut().unwrap(),
+                                    rbsm,
+                                    id,
+                                    self.sim_seqno,
+                                );
+                            }
+
+                            let entity_ids: Vec<u32> = rbsm.rb_entities.keys().copied().collect();
+                            for entity_id in entity_ids {
+                                rbsm.destroy_rb_entity(entity_id);
+                            }
+                        }
+                    }
                     KeyCode::Space if pressed => self.sim_paused = !self.sim_paused,
                     KeyCode::KeyX if pressed => self.ignore_pause_next_tick = true,
                     KeyCode::KeyQ if pressed && !repeat => self.input.trigger_test_1 = true,
-- 
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