asdf-games/lib/utilities/entity.js

const math = require("./math");
const Rect = require("../Rect");

function addDebug(e) {
	e.children = e.children || [];
	const bb = new Rect(e.w, e.h, { fill: "rgba(255, 0, 0, 0.3)" });
	e.children.push(bb);
	if (e.hitBox) {
		const { x, y, w, h } = e.hitBox;
		const hb = new Rect(w, h, { fill: "rgba(255, 0, 0, 0.5)" });
		hb.pos.x = x;
		hb.pos.y = y;
		e.children.push(hb);
	}
	return e;
}

function angle(a, b) {
	return math.angle(center(a), center(b));
}

function bounds(entity) {
	let pos, w, h, hitBox;
	// Object.prototype.hasOwnProperty.call is needed because of eslint
	if (Object.prototype.hasOwnProperty.call(entity, "tileW") && Object.prototype.hasOwnProperty.call(entity, "tileH")) {
		({pos, w, h} = {pos: entity.pos, w: entity.tileW, h: entity.tileH});
	} else {
		({pos, w, h} = entity);
	}

	if (entity.hitBox) hitBox = entity.hitBox;

	const hit = hitBox || { x: 0, y: 0, w, h };
	return {
		x: hit.x + pos.x,
		y: hit.y + pos.y,
		w: hit.w - 1,
		h: hit.h - 1
	};
}

function center(entity) {
	let pos, w, h;

	// Object.prototype.hasOwnProperty.call is needed because of eslint
	if (Object.prototype.hasOwnProperty.call(entity, "tileW") && Object.prototype.hasOwnProperty.call(entity, "tileH")) {
		({pos, w, h} = {pos: entity.pos, w: entity.tileW, h: entity.tileH});
	} else {
		({pos, w, h} = entity);
	}
	
	return {
		x: pos.x + w / 2,
		y: pos.y + h / 2
	};
}

function distance(a, b) {
	return math.distance(center(a), center(b));
}

function hit(e1, e2) {
	const a = bounds(e1);
	const b = bounds(e2);
	return (
		a.x + a.w >= b.x &&
    a.x <= b.x + b.w &&
    a.y + a.h >= b.y &&
    a.y <= b.y + b.h
	);
}

function hits(entity, container, hitCallback) {
	const a = bounds(entity);
	container.map(e2 => {
		const b = bounds(e2);
		if (
			a.x + a.w >= b.x &&
      a.x <= b.x + b.w &&
      a.y + a.h >= b.y &&
      a.y <= b.y + b.h
		) {
			hitCallback(e2);
		}
	});
}

module.exports = {
	addDebug,
	angle,
	bounds,
	center,
	distance,
	hit,
	hits
};