silphius/app/ecs-components/wielder.js

import Component from '@/ecs/component.js';

export default class Wielder extends Component {
  instanceFromSchema() {
    const Instance = super.instanceFromSchema();
    const Component = this;
    Instance.prototype.activeItem = async function () {
      const {Inventory, Wielder} = Component.ecs.get(this.entity);
      return Inventory.item(Wielder.activeSlot + 1);
    };
    Instance.prototype.project = function(position, projection) {
      const {TileLayers: {layers: [layer]}} = Component.ecs.get(1);
      const {Direction: {direction}} = Component.ecs.get(this.entity);
      let startX = position.x;
      let startY = position.y;
      switch (direction) {
        case 0:
          startX += projection.distance[1];
          startY -= projection.distance[0];
          break;
        case 1:
          startX += projection.distance[0];
          startY += projection.distance[1];
          break;
        case 2:
          startX -= projection.distance[1];
          startY += projection.distance[0];
          break;
        case 3:
          startX -= projection.distance[0];
          startY -= projection.distance[1];
          break;
      }
      const projected = [];
      for (const row in projection.grid) {
        const columns = projection.grid[row];
        for (const column in columns) {
          const targeted = projection.grid[row][column];
          if (targeted) {
            let axe;
            switch (direction) {
              case 0:
                axe = [column, row];
                break;
              case 1:
                axe = [-row, column];
                break;
              case 2:
                axe = [-column, -row];
                break;
              case 3:
                axe = [row, -column];
                break;
            }
            const x = startX + parseInt(axe[0]);
            const y = startY + parseInt(axe[1]);
            if (x < 0 || y < 0 || x >= layer.area.x || y >= layer.area.y) {
              continue;
            }
            projected.push({x, y});
          }
        }
      }
      return projected;
    }
    return Instance;
  }
  static properties = {
    activeSlot: {type: 'uint16'},
  };
}