refactor: ecs diff

app/ecs-systems/apply-control-movement.js

@@ -3,13 +3,9 @@ import {System} from '@/ecs/index.js';
 export default class ApplyControlMovement extends System {
 
   tick() {
-    const {diff} = this.ecs;
-    for (const id in diff) {
-      if (diff[id].Controlled) {
-        const {Controlled, Momentum, Speed} = this.ecs.get(id);
-        Momentum.x = Speed.speed * (Controlled.moveRight - Controlled.moveLeft);
-        Momentum.y = Speed.speed * (Controlled.moveDown - Controlled.moveUp);
-      }
+    for (const {Controlled, Momentum, Speed} of this.ecs.changed(['Controlled'])) {
+      Momentum.x = Speed.speed * (Controlled.moveRight - Controlled.moveLeft);
+      Momentum.y = Speed.speed * (Controlled.moveDown - Controlled.moveUp);
     }
   }
 

app/ecs-systems/calculate-aabbs.js

@@ -3,16 +3,12 @@ import {System} from '@/ecs/index.js';
 export default class CalculateAabbs extends System {
 
   tick() {
-    const {diff} = this.ecs;
-    for (const id in diff) {
-      if (diff[id].Position) {
-        const {Position: {x, y}, VisibleAabb} = this.ecs.get(id);
-        if (VisibleAabb) {
-          VisibleAabb.x0 = x - 32;
-          VisibleAabb.x1 = x + 32;
-          VisibleAabb.y0 = y - 32;
-          VisibleAabb.y1 = y + 32;
-        }
+    for (const {Position: {x, y}, VisibleAabb} of this.ecs.changed(['Position'])) {
+      if (VisibleAabb) {
+        VisibleAabb.x0 = x - 32;
+        VisibleAabb.x1 = x + 32;
+        VisibleAabb.y0 = y - 32;
+        VisibleAabb.y1 = y + 32;
       }
     }
   }

app/ecs-systems/clamp-positions.js

@@ -3,23 +3,19 @@ import {System} from '@/ecs/index.js';
 export default class ClampPositions extends System {
 
   tick() {
-    const {diff} = this.ecs;
     const {AreaSize} = this.ecs.get(1);
-    for (const id in diff) {
-      if (diff[id].Position) {
-        const {Position} = this.ecs.get(id);
-        if (Position.x < 0) {
-          Position.x = 0;
-        }
-        if (Position.y < 0) {
-          Position.y = 0;
-        }
-        if (Position.x >= AreaSize.x) {
-          Position.x = AreaSize.x - 0.0001;
-        }
-        if (Position.y >= AreaSize.y) {
-          Position.y = AreaSize.y - 0.0001;
-        }
+    for (const {Position} of this.ecs.changed(['Position'])) {
+      if (Position.x < 0) {
+        Position.x = 0;
+      }
+      if (Position.y < 0) {
+        Position.y = 0;
+      }
+      if (Position.x >= AreaSize.x) {
+        Position.x = AreaSize.x - 0.0001;
+      }
+      if (Position.y >= AreaSize.y) {
+        Position.y = AreaSize.y - 0.0001;
       }
     }
   }

app/ecs-systems/control-direction.js

@@ -3,23 +3,19 @@ import {System} from '@/ecs/index.js';
 export default class ControlDirection extends System {
 
   tick() {
-    const {diff} = this.ecs;
-    for (const id in diff) {
-      const {Controlled} = diff[id];
-      if (Controlled) {
-        const {Controlled: {moveUp, moveRight, moveDown, moveLeft}, Direction} = this.ecs.get(id);
-        if (moveUp > 0) {
-          Direction.direction = 0;
-        }
-        if (moveDown > 0) {
-          Direction.direction = 2;
-        }
-        if (moveLeft > 0) {
-          Direction.direction = 3;
-        }
-        if (moveRight > 0) {
-          Direction.direction = 1;
-        }
+    for (const {Controlled, Direction} of this.ecs.changed(['Controlled'])) {
+      const {moveUp, moveRight, moveDown, moveLeft} = Controlled;
+      if (moveUp > 0) {
+        Direction.direction = 0;
+      }
+      if (moveDown > 0) {
+        Direction.direction = 2;
+      }
+      if (moveLeft > 0) {
+        Direction.direction = 3;
+      }
+      if (moveRight > 0) {
+        Direction.direction = 1;
       }
     }
   }

app/ecs-systems/follow-camera.js

@@ -11,11 +11,8 @@ export default class FollowCamera extends System {
   }
 
   tick() {
-    const {diff} = this.ecs;
-    for (const id in diff) {
-      if (diff[id].Position) {
-        this.updateCamera(this.ecs.get(id));
-      }
+    for (const entity of this.ecs.changed(['Position'])) {
+      this.updateCamera(entity);
     }
   }
 

app/ecs-systems/update-spatial-hash.js

@@ -81,11 +81,8 @@ export default class UpdateSpatialHash extends System {
   }
 
   tick() {
-    const {diff} = this.ecs;
-    for (const id in diff) {
-      if (diff[id].VisibleAabb) {
-        this.updateHash(this.ecs.get(id));
-      }
+    for (const entity of this.ecs.changed(['VisibleAabb'])) {
+      this.updateHash(entity);
     }
   }
 

app/ecs/ecs.js

@@ -67,6 +67,32 @@ export default class Ecs {
     this.createManySpecific(creating);
   }
 
+  changed(criteria) {
+    const it = Object.entries(this.diff).values();
+    return {
+      [Symbol.iterator]() {
+        return this;
+      },
+      next: () => {
+        let result = it.next();
+        let satisfied = false;
+        while (!result.done) {
+          for (const componentName of criteria) {
+            if (!(componentName in result.value[1])) {
+              result = it.next();
+              continue;
+            }
+          }
+          break;
+        }
+        if (result.done) {
+          return {done: true, value: undefined};
+        }
+        return {done: false, value: this.get(result.value[0])};
+      },
+    };
+  }
+
   create(components = {}) {
     const [entityId] = this.createMany([components]);
     return entityId;