4 files changed, 59 insertions, 15 deletions
diff --git a/engine/src/event.rs b/engine/src/event.rs
index 8d5f805..e5ae486 100644
--- a/engine/src/event.rs
+++ b/engine/src/event.rs
@@ -20,3 +20,8 @@ impl Event for Present {}
 pub struct PostPresent;
 
 impl Event for PostPresent {}
+
+#[derive(Debug)]
+pub struct Conclude;
+
+impl Event for Conclude {}
diff --git a/engine/src/input.rs b/engine/src/input.rs
index e292b76..d1fb336 100644
--- a/engine/src/input.rs
+++ b/engine/src/input.rs
@@ -4,7 +4,11 @@ use ecs::extension::Collector as ExtensionCollector;
 use ecs::sole::Single;
 use ecs::Sole;
 
-use crate::event::{PreUpdate as PreUpdateEvent, Start as StartEvent};
+use crate::event::{
+    PostPresent as PostPresentEvent,
+    PreUpdate as PreUpdateEvent,
+    Start as StartEvent,
+};
 use crate::vector::Vec2;
 use crate::window::Window;
 
@@ -15,10 +19,10 @@ mod reexports
 
 pub use reexports::*;
 
-#[derive(Debug, Clone, Sole)]
+#[derive(Debug, Sole)]
 pub struct Keys
 {
-    map: HashMap<Key, KeyState>,
+    map: HashMap<Key, KeyData>,
 }
 
 impl Keys
@@ -29,7 +33,15 @@ impl Keys
         Self {
             map: Key::KEYS
                 .iter()
-                .map(|key| (*key, KeyState::Released))
+                .map(|key| {
+                    (
+                        *key,
+                        KeyData {
+                            state: KeyState::Released,
+                            prev_tick_state: KeyState::Released,
+                        },
+                    )
+                })
                 .collect(),
         }
     }
@@ -37,7 +49,16 @@ impl Keys
     #[must_use]
     pub fn get_key_state(&self, key: Key) -> KeyState
     {
-        self.map.get(&key).copied().expect("Key not in key map")
+        self.map.get(&key).expect("Key not in key map").state
+    }
+
+    #[must_use]
+    pub fn get_prev_key_state(&self, key: Key) -> KeyState
+    {
+        self.map
+            .get(&key)
+            .expect("Key not in key map")
+            .prev_tick_state
     }
 
     pub fn set_key_state(&mut self, key: Key, new_key_state: KeyState)
@@ -46,9 +67,9 @@ impl Keys
             return;
         }
 
-        let key_state = self.map.get_mut(&key).expect("Key not in key map");
+        let key_data = self.map.get_mut(&key).expect("Key not in key map");
 
-        *key_state = new_key_state;
+        key_data.state = new_key_state;
     }
 
     #[must_use]
@@ -56,7 +77,7 @@ impl Keys
     {
         self.map
             .values()
-            .any(|key_state| matches!(key_state, KeyState::Pressed))
+            .any(|key_data| matches!(key_data.state, KeyState::Pressed))
     }
 }
 
@@ -123,6 +144,7 @@ impl ecs::extension::Extension for Extension
     {
         collector.add_system(StartEvent, initialize);
         collector.add_system(PreUpdateEvent, maybe_clear_cursor_is_first_move);
+        collector.add_system(PostPresentEvent, set_keys_prev_tick_state);
 
         collector.add_sole(Keys::default()).ok();
         collector.add_sole(Cursor::default()).ok();
@@ -140,8 +162,6 @@ fn initialize(
     let keys_weak_ref = keys.to_weak_ref();
 
     window.set_key_callback(move |key, _scancode, key_state, _modifiers| {
-        let keys_weak_ref = keys_weak_ref.clone();
-
         let keys_ref = keys_weak_ref.access().expect("No world");
 
         let mut keys = keys_ref.to_single();
@@ -152,8 +172,6 @@ fn initialize(
     let cursor_weak_ref = cursor.to_weak_ref();
 
     window.set_cursor_pos_callback(move |cursor_position| {
-        let cursor_weak_ref = cursor_weak_ref.clone();
-
         let cursor_ref = cursor_weak_ref.access().expect("No world");
 
         let mut cursor = cursor_ref.to_single();
@@ -201,3 +219,17 @@ fn maybe_clear_cursor_is_first_move(
         cursor_flags.is_first_move.pending_clear = true;
     }
 }
+
+fn set_keys_prev_tick_state(mut keys: Single<Keys>)
+{
+    for key_data in keys.map.values_mut() {
+        key_data.prev_tick_state = key_data.state;
+    }
+}
+
+#[derive(Debug)]
+struct KeyData
+{
+    state: KeyState,
+    prev_tick_state: KeyState,
+}
diff --git a/engine/src/lib.rs b/engine/src/lib.rs
index 36e9285..5df2292 100644
--- a/engine/src/lib.rs
+++ b/engine/src/lib.rs
@@ -13,6 +13,7 @@ use ecs::{SoleAlreadyExistsError, World};
 
 use crate::delta_time::{update as update_delta_time, DeltaTime, LastUpdate};
 use crate::event::{
+    Conclude as ConcludeEvent,
     PostPresent as PostPresentEvent,
     PreUpdate as PreUpdateEvent,
     Present as PresentEvent,
@@ -48,7 +49,13 @@ pub extern crate ecs;
 pub(crate) use crate::data_types::matrix;
 pub use crate::data_types::{color, vector};
 
-type EventOrder = (PreUpdateEvent, UpdateEvent, PresentEvent, PostPresentEvent);
+type EventOrder = (
+    PreUpdateEvent,
+    UpdateEvent,
+    PresentEvent,
+    PostPresentEvent,
+    ConcludeEvent,
+);
 
 #[derive(Debug)]
 pub struct Engine
diff --git a/engine/src/window.rs b/engine/src/window.rs
index b308539..ccc1b8d 100644
--- a/engine/src/window.rs
+++ b/engine/src/window.rs
@@ -8,7 +8,7 @@ use ecs::Sole;
 use glfw::WindowSize;
 
 use crate::data_types::dimens::Dimens;
-use crate::event::{PostPresent as PostPresentEvent, Start as StartEvent};
+use crate::event::{Conclude as ConcludeEvent, Start as StartEvent};
 use crate::vector::Vec2;
 
 mod reexports
@@ -258,7 +258,7 @@ impl ecs::extension::Extension for Extension
     fn collect(self, mut collector: ExtensionCollector<'_>)
     {
         collector.add_system(StartEvent, initialize);
-        collector.add_system(PostPresentEvent, update);
+        collector.add_system(ConcludeEvent, update);
 
         let window = self
             .window_builder