top-down-action-adventure/src/room.js

import RoomObject from "./roomObject.js"

export default class Room {
  constructor(game, json, name) {
    this.game = game
    this.json = json
    this.name = name
    const objectJson = this.json.layers.find(layer => layer.type == "objectgroup")?.objects || []
    this.objects = objectJson.map(RoomObject.fromJson.bind(null, this.game))
  }

  tick(dt) {
    this.objects.forEach(object => object.tick(dt))
  }

  get tilesetsToLoad() {
    const ts = {}
    this.json.tilesets.forEach((tileset, index) => {
      ts[`${this.name}-${index}`] = tileset.source
    })
    return ts
  }

  populateTilesets(assets) {
    this.tilesets = this.json.tilesets.map((tileset, index) => {
      const ts = assets.get(`${this.name}-${index}`)
      ts.populateImage(assets)
      return ts
    })
  }

  draw(ctx) {
    this.json.layers.forEach(this.drawLayer.bind(this, ctx))
    this.objects.forEach(object => object.draw(ctx))
  }

  drawLayer(ctx, layer) {
    if (layer.type == "tilelayer") this.drawTileLayer(ctx, layer)
  }

  drawTileLayer(ctx, layer) {
    for (let y = 0; y < layer.height; y++) {
      for (let x = 0; x < layer.width; x++) {
	const index = x + (y * layer.width)
	const tileIndex = layer.data[index] - 1
	const tileset = this.tilesets[0]
	const [sx, sy] = tileset.tileOffset(tileIndex)
	ctx.drawImage(
	  tileset.image,
	  sx,
	  sy,
	  tileset.tileWidth,
	  tileset.tileHeight,
	  x * this.json.tilewidth,
	  y * this.json.tileheight,
	  this.json.tilewidth,
	  this.json.tileheight
	)
      }
    }
  }
}