tower/ts/projectile_tile_factory.ts

import { AnimatableTileFactory } from './animatable_tile_factory.js';
import { LayeredTileFactory } from './layered_tile_factory.js';
import { Tile } from './tile.js';
import { TileFactory } from './tile_factory.js';

export class ProjectileTileFactory extends TileFactory {
  source_tile_factory: AnimatableTileFactory;
  target_relative_x: number;
  target_relative_y: number;
  spin: number;
  speed: number;

  tile_factory: TileFactory;

  constructor(tile_factory: AnimatableTileFactory, target_relative_x: number, target_relative_y: number, spin: number, speed: number) {
    super(tile_factory.layer_name, tile_factory.width, tile_factory.height);

    this.source_tile_factory = tile_factory;
    this.target_relative_x = target_relative_x;
    this.target_relative_y = target_relative_y;
    this.spin = spin;
    this.speed = speed;

    const copy = tile_factory.copy();
    const distance = Math.sqrt(target_relative_x ** 2 + target_relative_y ** 2);

    copy.add_animation(
      'launch-x',
      [
        {
          'offset': 0.0,
          'easing': 'linear',
          'left': '0',
          'transform': 'rotate(0)',
        },
        {
          'offset': 1.0,
          'left': `${target_relative_x / tile_factory.width * 100}%`,
          'transform': `rotate(${Math.sign(target_relative_x) * distance * spin * 10}deg)`,
        },
      ],
      {
        'duration': distance * (1 / speed) * 100,
        'iterations': 1,
      },
    );

    copy.add_animation(
      'launch-y',
      [
        {
          'offset': 0.0,
          'easing': 'cubic-bezier(0.33, 0.66, 0.66, 1.00)',
          'top': '0',
        },
        {
          'offset': 0.50,
          'easing': 'cubic-bezier(0.33, 0.00, 0.66, 0.33)',
          'top': `-500%`,
        },
        {
          'offset': 1.0,
          'top': `${target_relative_y / tile_factory.height * 100}%`,
        },
      ],
      {
        'duration': distance * (1 / speed) * 100,
        'iterations': 1,
      },
    );

    this.tile_factory = new LayeredTileFactory([copy]);
  }

  build(tileset: string): Tile {
    const tile = this.tile_factory.build(tileset);
    tile.play('launch-x')!.finished.then(() => tile.remove());
    tile.play('launch-y');
    return tile;
  }

  copy(): ProjectileTileFactory {
    return new ProjectileTileFactory(
      this.source_tile_factory,
      this.target_relative_x,
      this.target_relative_y,
      this.spin,
      this.speed,
    );
  }
}