16 files changed, 180 insertions, 16 deletions
diff --git a/src/sim/cell.rs b/src/sim/cell/cell.rs
index d3ca302..d35fa76 100644
--- a/src/sim/cell.rs
+++ b/src/sim/cell/cell.rs
@@ -1,4 +1,4 @@
-use crate::sim::materials::MaterialId;
+use crate::sim::cell::materials::MaterialId;
 
 #[derive(Clone, Copy)]
 pub struct Cell {
diff --git a/src/sim/materials/fire.rs b/src/sim/cell/materials/fire.rs
index 97027d5..e0416b0 100644
--- a/src/sim/materials/fire.rs
+++ b/src/sim/cell/materials/fire.rs
@@ -1,6 +1,9 @@
 use rand::RngExt;
 
-use crate::sim::{cell::Cell, materials::MaterialId, sim::UpdateCtx};
+use crate::sim::{
+    cell::{cell::Cell, materials::MaterialId},
+    cell_sim::sim::UpdateCtx,
+};
 
 trait FireCellView {
     fn get_ticks_lived(self) -> u16;
diff --git a/src/sim/materials/gas.rs b/src/sim/cell/materials/gas.rs
index 8d9f42b..c0cd9f9 100644
--- a/src/sim/materials/gas.rs
+++ b/src/sim/cell/materials/gas.rs
@@ -1,4 +1,4 @@
-use crate::sim::sim::UpdateCtx;
+use crate::sim::cell_sim::sim::UpdateCtx;
 
 #[inline]
 pub fn sim_update(ctx: &mut UpdateCtx) {
diff --git a/src/sim/materials/mod.rs b/src/sim/cell/materials/mod.rs
index 10f0a06..a55ed51 100644
--- a/src/sim/materials/mod.rs
+++ b/src/sim/cell/materials/mod.rs
@@ -1,4 +1,4 @@
-use crate::sim::sim::UpdateCtx;
+use crate::sim::cell_sim::sim::UpdateCtx;
 
 mod fire;
 mod gas;
diff --git a/src/sim/materials/sand.rs b/src/sim/cell/materials/sand.rs
index ac8889f..d2d1265 100644
--- a/src/sim/materials/sand.rs
+++ b/src/sim/cell/materials/sand.rs
@@ -1,4 +1,4 @@
-use crate::sim::sim::UpdateCtx;
+use crate::sim::cell_sim::sim::UpdateCtx;
 
 #[inline]
 pub fn sim_update(ctx: &mut UpdateCtx) {
diff --git a/src/sim/materials/smoke.rs b/src/sim/cell/materials/smoke.rs
index 5240bc9..2ee7c00 100644
--- a/src/sim/materials/smoke.rs
+++ b/src/sim/cell/materials/smoke.rs
@@ -1,6 +1,6 @@
 use rand::RngExt;
 
-use crate::sim::sim::UpdateCtx;
+use crate::sim::cell_sim::sim::UpdateCtx;
 
 #[inline]
 pub fn sim_update(ctx: &mut UpdateCtx) {
diff --git a/src/sim/materials/water.rs b/src/sim/cell/materials/water.rs
index 1ba8eb4..4b848fb 100644
--- a/src/sim/materials/water.rs
+++ b/src/sim/cell/materials/water.rs
@@ -1,4 +1,4 @@
-use crate::sim::sim::UpdateCtx;
+use crate::sim::cell_sim::sim::UpdateCtx;
 
 #[inline]
 pub fn sim_update(ctx: &mut UpdateCtx) {
diff --git a/src/sim/cell/mod.rs b/src/sim/cell/mod.rs
new file mode 100644
index 0000000..2d2175c
--- /dev/null
+++ b/src/sim/cell/mod.rs
@@ -0,0 +1,2 @@
+pub mod cell;
+pub mod materials;
diff --git a/src/sim/chunk.rs b/src/sim/cell_sim/chunk.rs
index 478af12..116a38a 100644
--- a/src/sim/chunk.rs
+++ b/src/sim/cell_sim/chunk.rs
@@ -1,6 +1,6 @@
 use crate::{
     config::{CELLS_IN_CHUNK, CHUNK_SIZE},
-    sim::cell::Cell,
+    sim::cell::cell::Cell,
 };
 
 pub struct Chunk {
diff --git a/src/sim/cell_sim/mod.rs b/src/sim/cell_sim/mod.rs
new file mode 100644
index 0000000..a1db2a1
--- /dev/null
+++ b/src/sim/cell_sim/mod.rs
@@ -0,0 +1,4 @@
+pub mod chunk;
+pub mod overlay;
+pub mod sim;
+pub mod world;
diff --git a/src/sim/overlay.rs b/src/sim/cell_sim/overlay.rs
index c9fdf17..ee494ae 100644
--- a/src/sim/overlay.rs
+++ b/src/sim/cell_sim/overlay.rs
@@ -1,4 +1,4 @@
-use crate::{Config, Input, sim::world::World};
+use crate::{Config, Input, sim::cell_sim::world::World};
 
 pub fn create_compute_combined_overlay_offset(
     world: &World,
diff --git a/src/sim/sim.rs b/src/sim/cell_sim/sim.rs
index b9f4b76..fd9b6c9 100644
--- a/src/sim/sim.rs
+++ b/src/sim/cell_sim/sim.rs
@@ -6,7 +6,10 @@ use rayon::iter::{IntoParallelRefIterator, ParallelIterator};
 
 use crate::{
     config::CHUNK_SIZE,
-    sim::{cell::Cell, chunk::Chunk, materials::MaterialDef, world::World},
+    sim::{
+        cell::{cell::Cell, materials::MaterialDef},
+        cell_sim::{chunk::Chunk, world::World},
+    },
 };
 
 struct ChunkAccess<'a> {
diff --git a/src/sim/world.rs b/src/sim/cell_sim/world.rs
index d54906c..924639a 100644
--- a/src/sim/world.rs
+++ b/src/sim/cell_sim/world.rs
@@ -2,7 +2,7 @@ use fxhash::FxHashMap;
 
 use crate::{
     config::CHUNK_SIZE,
-    sim::{cell::Cell, chunk::Chunk},
+    sim::{cell::cell::Cell, cell_sim::chunk::Chunk},
 };
 
 pub struct World {
diff --git a/src/sim/mod.rs b/src/sim/mod.rs
index 7553f89..63a9c56 100644
--- a/src/sim/mod.rs
+++ b/src/sim/mod.rs
@@ -1,6 +1,3 @@
 pub mod cell;
-pub mod chunk;
-pub mod materials;
-pub mod overlay;
-pub mod sim;
-pub mod world;
+pub mod cell_sim;
+pub mod rb_sim;
diff --git a/src/sim/rb_sim/mod.rs b/src/sim/rb_sim/mod.rs
new file mode 100644
index 0000000..1818052
--- /dev/null
+++ b/src/sim/rb_sim/mod.rs
@@ -0,0 +1,131 @@
+pub mod rb_entity;
+
+use fxhash::FxHashMap;
+use rapier2d::{
+    dynamics::{self},
+    geometry,
+    glamx::vec2,
+    math, prelude,
+};
+
+use crate::{
+    config::{CELLS_IN_CHUNK, PHYSICS_DELTA_TIME},
+    sim::{
+        cell::{cell::Cell, materials::MaterialId},
+        rb_sim::rb_entity::RbEntity,
+    },
+};
+
+pub struct PhysicsManager {
+    rigid_body_set: prelude::RigidBodySet,
+    collider_set: prelude::ColliderSet,
+    physics_pipeline: prelude::PhysicsPipeline,
+    integration_parameters: prelude::IntegrationParameters,
+    island_manager: prelude::IslandManager,
+    broad_phase: prelude::DefaultBroadPhase,
+    narrow_phase: prelude::NarrowPhase,
+    impulse_joint_set: prelude::ImpulseJointSet,
+    multibody_joint_set: prelude::MultibodyJointSet,
+    ccd_solver: prelude::CCDSolver,
+}
+
+impl PhysicsManager {
+    pub fn new() -> Self {
+        PhysicsManager {
+            rigid_body_set: prelude::RigidBodySet::new(),
+            collider_set: prelude::ColliderSet::new(),
+            physics_pipeline: prelude::PhysicsPipeline::new(),
+            integration_parameters: prelude::IntegrationParameters {
+                // 20 pixels = 1 meter
+                length_unit: 20.0,
+                dt: PHYSICS_DELTA_TIME,
+                ..prelude::IntegrationParameters::default()
+            },
+            island_manager: prelude::IslandManager::new(),
+            broad_phase: prelude::DefaultBroadPhase::new(),
+            narrow_phase: prelude::NarrowPhase::new(),
+            impulse_joint_set: prelude::ImpulseJointSet::new(),
+            multibody_joint_set: prelude::MultibodyJointSet::new(),
+            ccd_solver: prelude::CCDSolver::new(),
+        }
+    }
+}
+
+pub struct RbSimManager {
+    physics_manager: PhysicsManager,
+    pub rb_entities: FxHashMap<u32, RbEntity>,
+}
+
+impl RbSimManager {
+    pub fn rb_tick(&mut self, delta_time: f32) {
+        let gravity = vec2(0.0, -9.81);
+
+        self.physics_manager.physics_pipeline.step(
+            gravity,
+            &self.physics_manager.integration_parameters,
+            &mut self.physics_manager.island_manager,
+            &mut self.physics_manager.broad_phase,
+            &mut self.physics_manager.narrow_phase,
+            &mut self.physics_manager.rigid_body_set,
+            &mut self.physics_manager.collider_set,
+            &mut self.physics_manager.impulse_joint_set,
+            &mut self.physics_manager.multibody_joint_set,
+            &mut self.physics_manager.ccd_solver,
+            &(),
+            &(),
+        );
+    }
+
+    pub fn get_rb_entity_position(&self, entity_id: u32) -> Option<(f32, f32)> {
+        let entity = self.rb_entities.get(&entity_id);
+        match entity {
+            Some(entity) => {
+                let rb = self.physics_manager.rigid_body_set.get(entity.rb_parent);
+                rb.map(|rb| (rb.position().translation.x, rb.position().translation.y))
+            }
+            None => return None,
+        }
+    }
+
+    pub fn test(&mut self) {
+        /* Create the ground. */
+        let collider = geometry::ColliderBuilder::cuboid(100.0, 0.1).build();
+        self.physics_manager.collider_set.insert(collider);
+
+        /* Create the bouncing ball. */
+        let rigid_body = dynamics::RigidBodyBuilder::dynamic()
+            .translation(math::Vector::new(0.0, 10.0))
+            .build();
+        let collider = geometry::ColliderBuilder::ball(0.5)
+            .restitution(0.7)
+            .build();
+        let ball_body_handle = self.physics_manager.rigid_body_set.insert(rigid_body);
+        self.physics_manager.collider_set.insert_with_parent(
+            collider,
+            ball_body_handle,
+            &mut self.physics_manager.rigid_body_set,
+        );
+
+        let test_cells = Box::new([Cell::void(); CELLS_IN_CHUNK]);
+        let mut rb_entity = RbEntity {
+            id: 0,
+            cells: test_cells,
+            rb_parent: ball_body_handle,
+        };
+
+        for x in 0..10 {
+            for y in 0..10 {
+                rb_entity.set_cell_at_local_position(x, y, Cell::from_material(MaterialId::Wood));
+            }
+        }
+
+        self.rb_entities.insert(0, rb_entity);
+    }
+
+    pub fn new() -> Self {
+        RbSimManager {
+            physics_manager: PhysicsManager::new(),
+            rb_entities: FxHashMap::default(),
+        }
+    }
+}
diff --git a/src/sim/rb_sim/rb_entity.rs b/src/sim/rb_sim/rb_entity.rs
new file mode 100644
index 0000000..50243bc
--- /dev/null
+++ b/src/sim/rb_sim/rb_entity.rs
@@ -0,0 +1,24 @@
+use rapier2d::prelude;
+
+use crate::{
+    config::{CELLS_IN_CHUNK, CHUNK_SIZE},
+    sim::cell::cell::Cell,
+};
+
+pub struct RbEntity {
+    pub id: u32,
+    // TODO resizable
+    pub cells: Box<[Cell; CELLS_IN_CHUNK]>,
+    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]
+    }
+    #[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;
+    }
+}