don't rebuild the ground each step

1 files changed, 28 insertions, 7 deletions

diff --git a/src/systems/makefloor.rs b/src/systems/makefloor.rs
index 8b550bc..74e4389 100644
--- a/src/systems/makefloor.rs
+++ b/src/systems/makefloor.rs
@@ -1,4 +1,5 @@
 
+use std::collections::HashSet;
 
 use specs::{
 	ReadStorage,
@@ -8,20 +9,40 @@ use specs::{
 	Join
 };
 
-use super::super::components::Position;
+use crate::components::{
+	Position,
+	New,
+	Moved,
+	Removed
+};
 
-use super::super::resources::{
+use crate::resources::{
 	Ground
 };
 
 
+#[derive(Default)]
 pub struct MakeFloor;
 impl <'a> System<'a> for MakeFloor {
-	type SystemData = (Entities<'a>, Write<'a, Ground>, ReadStorage<'a, Position>);
-	fn run(&mut self, (entities, mut ground, positions): Self::SystemData) {
-		ground.cells.clear();
-		for (ent, pos) in (&entities, &positions).join() {
-			ground.cells.entry(pos.pos).or_insert(Vec::new()).push(ent);
+	type SystemData = (
+		Entities<'a>,
+		Write<'a, Ground>,
+		ReadStorage<'a, Position>,
+		ReadStorage<'a, New>,
+		ReadStorage<'a, Moved>,
+		ReadStorage<'a, Removed>
+	);
+	fn run(&mut self, (entities, mut ground, positions, new, moved, removed): Self::SystemData) {
+		for (ent, pos, _new) in (&entities, &positions, &new).join() {
+			ground.cells.entry(pos.pos).or_insert(HashSet::new()).insert(ent);
+		}
+		for (ent, pos, mov) in (&entities, &positions, &moved).join() {
+			ground.cells.entry(pos.pos).or_insert(HashSet::new()).insert(ent);
+			ground.cells.get_mut(&mov.from).unwrap().remove(&ent);
+		}
+		for (ent, pos, _removed) in (&entities, &positions, &removed).join() {
+			ground.cells.get_mut(&pos.pos).unwrap().remove(&ent);
 		}
 	}
 }
+