make projectiles use bounding boxes too

src/projectile.js

@@ -36,17 +36,6 @@ export default class Projectile {
     }
   }
 
-  checkCollisions(collider) {
-    (this.game?.entities ?? []).filter((e) => e.id != this.id).forEach((e) => {
-      if (this.game == null) { return }
-      if (e.id == this.owner?.id) { return }
-
-      if (SATX.collideObject(collider, e.collider())) {
-        if (this.onCollide != null) { this.onCollide(this, e) }
-      }
-    })
-  }
-
   collider() {
     return new SAT.Circle(new SAT.Vector(this.position.x, this.position.y), this.radius)
   }
@@ -55,10 +44,14 @@ export default class Projectile {
     this.game?.despawn(this)
   }
 
+  setPosition(vector) {
+    this.position.copy(vector)
+    this.#calculateBbox()
+  }
+
   update() {
     this.#move()
-    this.#calculateBbox()
-    if (this.onCollide != null) { this.checkCollisions(this.collider()) }
+    this.#checkStationaryCollisions()
     this.#checkIfArrived()
   }
 
@@ -80,21 +73,41 @@ export default class Projectile {
     this.despawn()
   }
 
+  #checkStationaryCollisions() {
+    if (this.onCollide == null) { return }
+
+    const bbox = this.bbox
+    const entitiesAndTerrains = this.game?.entities ?? []
+    const bboxCheckedObstacles = entitiesAndTerrains.filter((it) => SATX.bboxCheck(bbox, it.bbox))
+    if (bboxCheckedObstacles.length > 0) {
+      const colliders = bboxCheckedObstacles.map((it) => it.colliders()).flat()
+      const collider = this.collider()
+      colliders.filter((it) => SATX.collideObject(collider, it)).forEach((it) => this.onCollide(this, it))
+    }
+  }
+
   #move() {
     if (this.destination == null) { return }
 
     const speed = (this.speed / (this.game?.tickBudget ?? 1000))
     const prevPos = this.position.clone()
     if (this.position.distanceTo(this.destination) < speed) {
-      this.position.copy(this.destination)
+      this.setPosition(this.destination)
     }
     else {
       const step = this.destination.clone().sub(this.position).normalize().multiplyScalar(speed)
       this.position.add(step)
     }
 
-    // TODO: decouple from entity's tunnel collider
-    const tunnel = Entity.tunnelCollider(prevPos.x, prevPos.y, this.position.x, this.position.y, this.radius)
-    if (this.onCollide != null) { this.checkCollisions(tunnel) }
+    if (this.onCollide != null) {
+      const bbox = Entity.tunnelBbox(position.x, position.y, destination.x, destination.y, this.radius)
+      const entitiesAndTerrains = this.game?.entities ?? []
+      const bboxCheckedObstacles = entitiesAndTerrains.filter((it) => SATX.bboxCheck(bbox, it.bbox))
+      if (bboxCheckedObstacles.length > 0) {
+        const colliders = bboxCheckedObstacles.map((it) => it.colliders()).flat()
+        const collider = Entity.tunnelCollider(prevPos.x, prevPos.y, this.position.x, this.position.y, this.radius)
+        colliders.filter((it) => SATX.collideObject(collider, it)).forEach((it) => this.onCollide(this, it))
+      }
+    }
   }
 }