3 files changed, 64 insertions, 22 deletions
diff --git a/Djup.Native/Constants.cs b/Djup.Native/Constants.cs
new file mode 100644
index 0000000..90692be
--- /dev/null
+++ b/Djup.Native/Constants.cs
@@ -0,0 +1,7 @@
+namespace Djup.Native;
+
+public static class Constants
+{
+    public const int WorldMaxPlayers = 5;
+    public const int WorldMaxBullets = 5000;
+}
diff --git a/Djup.Native/LibDjup.cs b/Djup.Native/LibDjup.cs
index 0b4a3db..15dcdad 100644
--- a/Djup.Native/LibDjup.cs
+++ b/Djup.Native/LibDjup.cs
@@ -31,21 +31,24 @@ public static partial class LibDjup
     [LibraryImport(LibraryName, EntryPoint = Prefix + nameof(log_set_level))]
     public static partial Vec2 log_set_level(LogLevel minLevel);
 
-    [LibraryImport(LibraryName, EntryPoint = Prefix + nameof(world_create))]
-    public static partial IntPtr world_create();
+    [LibraryImport(LibraryName, EntryPoint = Prefix + nameof(physics_context_create))]
+    public static partial IntPtr physics_context_create(uint snapshots);
 
-    [LibraryImport(LibraryName, EntryPoint = Prefix + nameof(world_free))]
-    public static partial void world_free(IntPtr world);
+    [LibraryImport(LibraryName, EntryPoint = Prefix + nameof(physics_context_free))]
+    public static partial void physics_context_free(IntPtr context);
 
-    [LibraryImport(LibraryName, EntryPoint = Prefix + nameof(world_create_entity))]
-    public static partial int world_create_entity(IntPtr world, EntityKind kind);
+    [LibraryImport(LibraryName, EntryPoint = Prefix + nameof(physics_context_get_snapshot))]
+    public static partial IntPtr physics_context_get_snapshot(IntPtr context);
 
-    [LibraryImport(LibraryName, EntryPoint = Prefix + nameof(world_find_entity))]
-    public static unsafe partial Entity* world_find_entity(IntPtr world, int entityId);
+    [LibraryImport(LibraryName, EntryPoint = Prefix + nameof(physics_context_return_snapshot))]
+    public static partial void physics_context_return_snapshot(IntPtr context, IntPtr snapshot);
 
-    [LibraryImport(LibraryName, EntryPoint = Prefix + nameof(world_remove_entity))]
-    public static partial void world_remove_entity(IntPtr world, int entityId);
+    [LibraryImport(LibraryName, EntryPoint = Prefix + nameof(physics_tick))]
+    public static partial int physics_tick(IntPtr currentSnapshot, double delta, IntPtr nextSnapshot);
 
-    [LibraryImport(LibraryName, EntryPoint = Prefix + nameof(world_tick))]
-    public static partial int world_tick(IntPtr world, double delta);
+    [LibraryImport(LibraryName, EntryPoint = Prefix + nameof(snapshot_put_player))]
+    public static unsafe partial int snapshot_put_player(IntPtr snapshot, uint playerId, Player *player);
+
+    [LibraryImport(LibraryName, EntryPoint = Prefix + nameof(snapshot_set_player_input))]
+    public static partial int snapshot_set_player_input(IntPtr snapshot, uint playerId, byte input);
 }
diff --git a/Djup.Native/Types.cs b/Djup.Native/Types.cs
index 478208f..7d9c41e 100644
--- a/Djup.Native/Types.cs
+++ b/Djup.Native/Types.cs
@@ -1,4 +1,5 @@
 using System.Diagnostics;
+using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 
 namespace Djup.Native;
@@ -21,29 +22,60 @@ public struct Vec2
     public override string ToString() => $"({X}, {Y})";
 }
 
-public enum EntityKind
+public enum EntityState : byte
 {
-    None = 0,
-    Ball
+    Inactive = 0,
+    Active,
+    Removed,
+    Dead
 }
 
-[StructLayout(LayoutKind.Explicit)]
-public struct Entity
+public enum PlayerInput : byte
 {
-    [FieldOffset(0)]
-    public EntityKind kind;
+    Up = 1 << 0,
+    Down = 1 << 1,
+    Left = 1 << 2,
+    Right = 1 << 3
+}
 
-    [FieldOffset(4)]
-    public Ball ball;
+[StructLayout(LayoutKind.Sequential)]
+public struct Player
+{
+    public EntityState State { get; }
+    private byte input;
+    public Vec2 Position { get; set; }
+    public Vec2 Velocity { get; set; }
 }
 
 [StructLayout(LayoutKind.Sequential)]
-public struct Ball
+public struct Bullet
 {
+    public EntityState State { get; set; }
     public Vec2 Position { get; set; }
     public Vec2 Velocity { get; set; }
 }
 
+[StructLayout(LayoutKind.Sequential)]
+public struct Snapshot
+{
+    [InlineArray(Constants.WorldMaxPlayers)]
+    public struct PlayerArray
+    {
+        private Player _element0;
+    }
+
+    [InlineArray(Constants.WorldMaxBullets)]
+    public struct BallArray
+    {
+        private Bullet _element0;
+    }
+
+    private byte active;
+    public uint Tick { get; }
+    public PlayerArray Players { get; }
+    public BallArray Bullets { get; }
+}
+
 public enum LogLevel
 {
     Trace,