From 9cf77a1d2bc33b65937035b63fe5bfe10f73d96c Mon Sep 17 00:00:00 2001
From: cha0s <git@cha0s.io>
Date: Tue, 11 Jun 2024 02:10:08 -0500
Subject: [PATCH] fix: spatial nearby

---
 app/ecs-systems/update-spatial-hash.js | 20 ++++++++++++++++++++
 app/ecs/ecs.test.js                    |  2 ++
 app/engine/engine.js                   |  8 +-------
 app/engine/engine.test.js              | 10 +++++-----
 4 files changed, 28 insertions(+), 12 deletions(-)

diff --git a/app/ecs-systems/update-spatial-hash.js b/app/ecs-systems/update-spatial-hash.js
index b23134e..98467e7 100644
--- a/app/ecs-systems/update-spatial-hash.js
+++ b/app/ecs-systems/update-spatial-hash.js
@@ -95,4 +95,24 @@ export default class UpdateSpatialHash extends System {
     }
   }
 
+  nearby(entity) {
+    const [cx0, cy0] = this.hash.chunkIndex(
+      entity.Position.x - RESOLUTION[0] * 0.75,
+      entity.Position.y - RESOLUTION[0] * 0.75,
+    );
+    const [cx1, cy1] = this.hash.chunkIndex(
+      entity.Position.x + RESOLUTION[0] * 0.75,
+      entity.Position.y + RESOLUTION[0] * 0.75,
+    );
+    const nearby = new Set();
+    for (let cy = cy0; cy <= cy1; ++cy) {
+      for (let cx = cx0; cx <= cx1; ++cx) {
+        this.hash.chunks[cx][cy].forEach((id) => {
+          nearby.add(this.ecs.get(id));
+        });
+      }
+    }
+    return nearby;
+  }
+
 }
diff --git a/app/ecs/ecs.test.js b/app/ecs/ecs.test.js
index ab17b8a..a78c0f2 100644
--- a/app/ecs/ecs.test.js
+++ b/app/ecs/ecs.test.js
@@ -439,6 +439,8 @@ test('serializes and deserializes', () => {
   expect(deserialized.get(16).constructor.types)
     .to.deep.equal(['Name', 'Position']);
   // Entity values.
+  expect(JSON.stringify(deserialized.get(1)))
+    .to.equal(JSON.stringify({Empty: {}, Position: {x: 64}}))
   expect(JSON.stringify(deserialized.get(1).Position))
     .to.equal(JSON.stringify({x: 64}));
   expect(JSON.stringify(deserialized.get(16).Position))
diff --git a/app/engine/engine.js b/app/engine/engine.js
index 6edfb67..0d07f8c 100644
--- a/app/engine/engine.js
+++ b/app/engine/engine.js
@@ -139,13 +139,7 @@ export default class Engine {
     const {entity, memory} = this.connectedPlayers.get(connection);
     const mainEntityId = entity.id;
     const ecs = this.ecses[entity.World.world];
-    const {hash} = ecs.system(UpdateSpatialHash);
-    const nearby = new Set();
-    for (const [cx, cy] of hash.data[entity.id]) {
-      hash.chunks[cx][cy].forEach((id) => {
-        nearby.add(ecs.get(id));
-      });
-    }
+    const nearby = ecs.system(UpdateSpatialHash).nearby(entity);
     const lastMemory = new Set(memory.values());
     for (const entity of nearby) {
       const {id} = entity;
diff --git a/app/engine/engine.test.js b/app/engine/engine.test.js
index 276c98c..ba445ab 100644
--- a/app/engine/engine.test.js
+++ b/app/engine/engine.test.js
@@ -10,7 +10,7 @@ test('visibility-based updates', async () => {
   // Create an entity.
   const entity = ecs.get(ecs.create({
     Momentum: {x: 1, y: 0},
-    Position: {x: (RESOLUTION[0] / 2) + 32 - 3, y: 20},
+    Position: {x: RESOLUTION[0] + 32 - 3, y: 20},
     VisibleAabb: {},
   }));
   // Connect an entity.
@@ -18,16 +18,16 @@ test('visibility-based updates', async () => {
   // Tick and get update. Should be a full update.
   engine.tick(1);
   expect(engine.updateFor(undefined))
-    .to.deep.equal({2: ecs.get(2).toJSON(), 3: ecs.get(3).toJSON()});
+    .to.deep.equal({2: ecs.get(2).toJSON(), 3: {MainEntity: {}, ...ecs.get(3).toJSON()}});
   // Tick and get update. Should be a partial update.
   engine.tick(1);
   expect(engine.updateFor(undefined))
     .to.deep.equal({
       2: {
-        Position: {x: (RESOLUTION[0] / 2) + 32 - 1},
+        Position: {x: RESOLUTION[0] + 32 - 1},
         VisibleAabb: {
-          x0: 399,
-          x1: 463,
+          x0: 799,
+          x1: 863,
         },
       },
     });