From e2842ade3fda3ccc74693a1541c48ecc2e00e42c Mon Sep 17 00:00:00 2001
From: Erik Onarheim <erik.onarheim@gmail.com>
Date: Fri, 1 Nov 2024 22:32:31 -0500
Subject: [PATCH] perf: Low hanging perf loop changes

---
 src/engine/Debug/DebugSystem.ts             |  3 ++-
 src/engine/Graphics/GraphicsSystem.ts       |  6 ++++--
 src/engine/Graphics/OffscreenSystem.ts      |  3 ++-
 src/engine/Scene.ts                         | 15 ++++++++-------
 src/engine/TileMap/IsometricEntitySystem.ts |  3 ++-
 5 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/src/engine/Debug/DebugSystem.ts b/src/engine/Debug/DebugSystem.ts
index 81e09cff..3aba0494 100644
--- a/src/engine/Debug/DebugSystem.ts
+++ b/src/engine/Debug/DebugSystem.ts
@@ -70,7 +70,8 @@ export class DebugSystem extends System {
     const bodySettings = this._engine.debug.body;
 
     const cameraSettings = this._engine.debug.camera;
-    for (const entity of this.query.entities) {
+    for (let i = 0; i < this.query.entities.length; i++) {
+      const entity = this.query.entities[i];
       if (entity.hasTag('offscreen')) {
         // skip offscreen entities
         continue;
diff --git a/src/engine/Graphics/GraphicsSystem.ts b/src/engine/Graphics/GraphicsSystem.ts
index 4279d296..484868ea 100644
--- a/src/engine/Graphics/GraphicsSystem.ts
+++ b/src/engine/Graphics/GraphicsSystem.ts
@@ -252,7 +252,8 @@ export class GraphicsSystem extends System {
    */
   private _applyTransform(entity: Entity): void {
     const ancestors = entity.getAncestors();
-    for (const ancestor of ancestors) {
+    for (let i = 0; i < ancestors.length; i++) {
+      const ancestor = ancestors[i];
       const transform = ancestor?.get(TransformComponent);
       const optionalBody = ancestor?.get(BodyComponent);
       if (transform) {
@@ -274,7 +275,8 @@ export class GraphicsSystem extends System {
 
   private _applyOpacity(entity: Entity): void {
     const ancestors = entity.getAncestors();
-    for (const ancestor of ancestors) {
+    for (let i = 0; i < ancestors.length; i++) {
+      const ancestor = ancestors[i];
       const maybeGraphics = ancestor?.get(GraphicsComponent);
       this._graphicsContext.opacity *= maybeGraphics?.opacity ?? 1;
     }
diff --git a/src/engine/Graphics/OffscreenSystem.ts b/src/engine/Graphics/OffscreenSystem.ts
index eca38e00..69840688 100644
--- a/src/engine/Graphics/OffscreenSystem.ts
+++ b/src/engine/Graphics/OffscreenSystem.ts
@@ -36,7 +36,8 @@ export class OffscreenSystem extends System {
     let graphics: GraphicsComponent;
     let maybeParallax: ParallaxComponent | undefined;
 
-    for (const entity of this.query.entities) {
+    for (let i = 0; i < this.query.entities.length; i++) {
+      const entity = this.query.entities[i];
       graphics = entity.get(GraphicsComponent);
       transform = entity.get(TransformComponent);
       maybeParallax = entity.get(ParallaxComponent);
diff --git a/src/engine/Scene.ts b/src/engine/Scene.ts
index 8102ff4b..c19af98e 100644
--- a/src/engine/Scene.ts
+++ b/src/engine/Scene.ts
@@ -718,14 +718,15 @@ export class Scene<TActivationData = unknown> implements CanInitialize, CanActiv
   }
 
   private _collectActorStats(engine: Engine) {
-    const screenElements = this.actors.filter((a) => a instanceof ScreenElement) as ScreenElement[];
-    for (const _ui of screenElements) {
-      engine.stats.currFrame.actors.ui++;
-    }
-
-    for (const actor of this.actors) {
+    const actors = this.actors;
+    for (let i = 0; i < actors.length; i++) {
+      const actor = actors[i];
+      if (actor instanceof ScreenElement) {
+        engine.stats.currFrame.actors.ui++;
+      }
       engine.stats.currFrame.actors.alive++;
-      for (const child of actor.children) {
+      for (let j = 0; j < actor.children.length; j++) {
+        const child = actor.children[j];
         if (isScreenElement(child as Actor)) {
           // TODO not true
           engine.stats.currFrame.actors.ui++;
diff --git a/src/engine/TileMap/IsometricEntitySystem.ts b/src/engine/TileMap/IsometricEntitySystem.ts
index 6575c5e6..d518dd35 100644
--- a/src/engine/TileMap/IsometricEntitySystem.ts
+++ b/src/engine/TileMap/IsometricEntitySystem.ts
@@ -16,7 +16,8 @@ export class IsometricEntitySystem extends System {
   update(): void {
     let transform: TransformComponent;
     let iso: IsometricEntityComponent;
-    for (const entity of this.query.entities) {
+    for (let i = 0; i < this.query.entities.length; i++) {
+      const entity = this.query.entities[i];
       transform = entity.get(TransformComponent);
       iso = entity.get(IsometricEntityComponent);
 
-- 
2.51.2