fix: weird bug in the ComponentStorage where due to the implementation of the SparseSet, components weren't correctly managed

crates/comet_app/src/app.rs

@@ -147,8 +147,8 @@ impl App {
 		self.input_manager.key_released(key)
 	}
 
-	pub fn new_entity(&mut self) -> u32 {
+	pub fn new_entity(&mut self) -> usize{
-		self.world.new_entity()
+		self.world.new_entity() as usize
 	}
 
 	pub fn delete_entity(&mut self, entity_id: usize) {

crates/comet_structs/src/column.rs

@@ -281,7 +281,7 @@ impl Column {
 		}
 	}
 
-	fn swap(&mut self, index1: usize, index2: usize) {
+	pub fn swap(&mut self, index1: usize, index2: usize) {
 		assert!(index1 < self.data.len() && index2 < self.data.len(), "Index out of bounds");
 
 		unsafe {

crates/comet_structs/src/component_storage.rs

@@ -26,7 +26,7 @@ impl ComponentStorage {
 
 	pub fn set_component<T: 'static>(&mut self, index: usize, element: T) {
 		if let Some(sparse_set) = self.get_mut(&TypeId::of::<T>()) {
-			sparse_set.set(index, element);
+			sparse_set.insert(index, element);
 		}
 		else {
 			error!("Component {:?} is not registered", TypeId::of::<T>());

crates/comet_structs/src/sparse_set.rs

@@ -1,77 +1,59 @@
 use crate::Column;
 use std::hash::{
 	Hash,
-	Hasher
 };
-use std::ptr;
 
 #[derive(Debug, Clone)]
 pub struct SparseSet {
-	sparse: Vec<Option<usize>>,
+	pub sparse: Vec<Option<usize>>,
-	dense: Column,
+	pub dense: Column,
-	len: usize
 }
 
 impl SparseSet {
 	pub fn new<T: 'static>(capacity: usize) -> Self {
 		Self {
-			sparse: Vec::with_capacity(capacity),
+			sparse: Vec::new(),
 			dense: Column::new::<T>(capacity),
-			len: 0
 		}
 	}
 
-	pub fn set<T: 'static>(&mut self, index: usize, element: T) {
+	pub fn insert<T: 'static>(&mut self, index: usize, value: T) {
 		if index >= self.sparse.len() {
-			self.sparse.resize_with(index + 1, || None);
+			self.sparse.resize(index + 1, None);
-		}
-
-		if let Some(column_index) = self.sparse[index] {
-			// Explicitly drop the existing component before replacing it
-			unsafe {
-				let existing_ptr = self.dense.data.get_unchecked_mut(column_index) as *mut T;
-				ptr::drop_in_place(existing_ptr);
-				ptr::write(existing_ptr, element);
-			}
-		} else {
-			let column_index = unsafe { self.dense.data.push_uninit() };
-			unsafe {
-				self.dense.data.initialize_unchecked(column_index, &element as *const T as *mut u8);
-			}
-			self.sparse[index] = Some(column_index);
-			self.len += 1;
 		}
+		self.sparse[index] = Some(self.dense.data.len());
+		self.dense.push(value);
 	}
 
 	pub fn remove<T: 'static>(&mut self, index: usize) -> Option<T>{
-		if index >= self.sparse.len() || self.sparse[index] == None {
+		if let Some(sparse_index) = self.sparse.get(index).and_then(|x| x.as_ref()) {
-			return None;
+			let dense_index = *sparse_index;
+			let last_index = self.dense.data.len() - 1;
+			if dense_index != last_index {
+				self.dense.swap(dense_index, last_index);
+				if let Some(sparse) = self.sparse.get_mut(last_index) {
+					*sparse = Some(dense_index);
+				}
 			}
-
-		let column_index = self.sparse[index];
-		let element = unsafe {
-			self.dense.data.swap_remove_and_forget_unchecked(column_index.unwrap())
-		};
-
 			self.sparse[index] = None;
-		self.len -= 1;
+			self.dense.remove::<T>(last_index)
-
+		}
-		Some(unsafe { ptr::read(element as *const T) })
+		else {
+			None
+		}
 	}
 
 	pub fn get<T: 'static>(&self, index: usize) -> Option<&T> {
-		if index >= self.sparse.len() || self.sparse[index] == None {
+		match self.sparse.get(index).and_then(|x| x.as_ref()) {
-			return None;
+			Some(sparse_index) => self.dense.get::<T>(*sparse_index),
+			None => None,
 		}
-
-		self.dense.get::<T>(index)
 	}
 
 	pub fn get_mut<T: 'static>(&mut self, index: usize) -> Option<&mut T> {
-		if index >= self.sparse.len() || self.sparse[index] == None {
+		match self.sparse.get(index).and_then(|x| x.as_ref()) {
-			return None;
+			Some(sparse_index) => self.dense.get_mut::<T>(*sparse_index),
-		}
+			None => None,
-
+		}
-		self.dense.get_mut::<T>(index)
 	}
 }