@phaserjs/phaser/geom/rectangle/GetRectangleMarchingAnts.js

Phaser 4

/**
 * @author       Richard Davey <rich@photonstorm.com>
 * @copyright    2020 Photon Storm Ltd.
 * @license      {@link https://opensource.org/licenses/MIT|MIT License}
 */
import { GetRectanglePerimeter } from "./GetRectanglePerimeter";
import { Vec2 } from "../../math/vec2/Vec2";
export function GetRectangleMarchingAnts(rect, step, quantity, out = []) {
  if (!step && !quantity) {
    return out;
  }
  if (!step) {
    step = GetRectanglePerimeter(rect) / quantity;
  } else {
    quantity = Math.round(GetRectanglePerimeter(rect) / step);
  }
  let x = rect.x;
  let y = rect.y;
  let face = 0;
  for (let i = 0; i < quantity; i++) {
    out.push(new Vec2(x, y));
    switch (face) {
      case 0:
        x += step;
        if (x >= rect.right) {
          face = 1;
          y += x - rect.right;
          x = rect.right;
        }
        break;
      case 1:
        y += step;
        if (y >= rect.bottom) {
          face = 2;
          x -= y - rect.bottom;
          y = rect.bottom;
        }
        break;
      case 2:
        x -= step;
        if (x <= rect.x) {
          face = 3;
          y -= rect.x - x;
          x = rect.x;
        }
        break;
      case 3:
        y -= step;
        if (y <= rect.y) {
          face = 0;
          y = rect.y;
        }
        break;
    }
  }
  return out;
}