feat: Add powerup component

src/com/Powerup.ts

@@ -0,0 +1,37 @@
+import { k } from '../kaboom';
+import { Comp } from 'kaboom';
+
+const {
+   anchor,
+   area,
+   destroy,
+   lifespan,
+   rand,
+   sprite,
+} = k;
+
+export interface PowerupComp extends Comp {
+   timeout: number,
+   type: 0 | 1 | 2;
+   points: ()=>number;
+}
+
+export function powerup(): PowerupComp {
+   return {
+      id: "powerup",
+      require: ["pos"],
+      timeout: 20,
+      type: Math.floor(rand() * 3) as 0 | 1 | 2, // Random int between 0-2
+      points: ()=>this.type*100 + Math.floor(rand()*99),
+      add() {
+         this.use(sprite('powerups', { frame: this.type }));
+         this.use(anchor('center'));
+         this.use(area({ scale: 0.6 }));
+         this.use(lifespan(this.timeout));
+         this.onCollide('player', player=>{
+            player.saltQty+=1;
+            destroy(this);
+         });
+      },
+   };
+}

src/main.ts

@@ -53,6 +53,7 @@ loadSprite("floor-stair-green", "floor-stair-green.png", { sliceX: 2 });
 loadSprite("head-h", "head-h.png");
 loadSprite("head-p", "head-p.png");
 loadSprite("plate", "plate.png", { sliceX: 2 });
+loadSprite("powerups", "powerups.png", { sliceX: 3 });
 loadSprite("salt", "salt.png", { sliceX: 4 });
 loadSprite("stair-blue", "stair-blue.png", { sliceX: 2 });
 loadSprite("stair-green", "stair-green.png", { sliceX: 2 });

src/scenes/GameScene.ts

@@ -5,6 +5,7 @@ import {
    SpriteComp,
 } from 'kaboom';
 import { k } from '../kaboom';
+import { powerup } from '../com/Powerup';
 import { peter, PeterComp } from '../com/Peter';
 import { canSalt, SaltComp } from '../com/Salt';
 import { canWalk, WalkComp, WalkableObj } from '../com/Walk';
@@ -16,9 +17,11 @@ const {
    anchor,
    area,
    fixed,
+   rand,
    Rect,
    sprite,
    vec2,
+   wait,
    z,
 } = k;
 
@@ -73,8 +76,13 @@ const levelConf: LevelOpt = {
          peter(),
          canSalt(),
          canWalk(),
+         z(10),
          "player",
       ],
+      '$': () => [
+         powerup(),
+         z(5),
+      ],
    },
 };
 
@@ -114,4 +122,13 @@ export default function(levelNumber = 0) {
    // Player setup
    const player: GameObj<PeterComp & PosComp & SpriteComp & SaltComp & WalkComp> = level.spawn("p", 16, 21.625);
    player.setObjects({ floors, stairs, stairtops });
+
+   // Powerups
+   function waitSpawnPowerup() {
+      // Wait 20-60 seconds
+      wait(rand()*40+20, ()=>{
+         level.spawn('$', 16, 13.5).onDestroy(waitSpawnPowerup)
+      });
+   }
+   waitSpawnPowerup();
 }