@bitsy/hecks/src/multi-sprite avatar.js

a collection of re-usable scripts for bitsy game maker

/**
👨‍👨‍👧‍👧
@file multi-sprite avatar
@summary make the player big
@license MIT
@version 2.1.5
@author Sean S. LeBlanc

@description
Allows multiple sprites to be moved together along with the player
to create the illusion of a larger avatar.

Provided example is a 2x2 square for simplicity,
but multi-sprite avatar's shape can be arbitrary.

Notes:
- will probably break any other hacks involving moving other sprites around (they'll probably use the player's modified collision)
- the original avatar sprite isn't changed, but will be covered by a piece at x:0,y:0
- make sure not to include the original avatar sprite in the pieces list (this will cause the syncing to remove the player from the game)

HOW TO USE:
1. Copy-paste into a script tag after the bitsy source
2. Edit `pieces` below to customize the multi-sprite avatar
	Pieces must have an x,y offset and a sprite id
*/
import bitsy from "bitsy";
import {
	before,
	after
} from "./helpers/kitsy-script-toolkit";
import {
	getImage
} from "./helpers/utils";

export var hackOptions = {
	pieces: [{
		x: 0,
		y: 0,
		spr: 'c'
	}, {
		x: 1,
		y: 0,
		spr: 'd'
	}, {
		x: 0,
		y: 1,
		spr: 'e'
	}, {
		x: 1,
		y: 1,
		spr: 'f'
	}],
	enabledOnStart: true
};

if (hackOptions.enabledOnStart) {
	after("onready", enableBig);
}

var enabled = false;
var pieces = [];

function syncPieces() {
	var p = bitsy.player();
	for (var i = 0; i < pieces.length; ++i) {
		var piece = pieces[i];
		var spr = getImage(piece.spr, bitsy.sprite);

		spr.room = p.room;
		spr.x = p.x + piece.x;
		spr.y = p.y + piece.y;
	}
}

function enableBig(newPieces) {
	disableBig();
	pieces = newPieces || hackOptions.pieces;
	enabled = true;
	syncPieces();
}

function disableBig() {
	enabled = false;
	for (var i = 0; i < pieces.length; ++i) {
		getImage(pieces[i].spr, bitsy.sprite).room = null;
	}
}

// handle item/ending/exit collision
var _getItemIndex = bitsy.getItemIndex;
var _getEnding = bitsy.getEnding;
var _getExit = bitsy.getExit;
var getItemIndexOverride = function (roomId, x, y) {
	for (var i = 0; i < pieces.length; ++i) {
		var piece = pieces[i];
		var idx = _getItemIndex(roomId, x + piece.x, y + piece.y);
		if (idx !== -1) {
			return idx;
		}
	}
	return -1;
};
var getEndingOverride = function (roomId, x, y) {
	for (var i = 0; i < pieces.length; ++i) {
		var piece = pieces[i];
		var e = _getEnding(roomId, x + piece.x, y + piece.y);
		if (e) {
			return e;
		}
	}
}
var getExitOverride = function (roomId, x, y) {
	for (var i = 0; i < pieces.length; ++i) {
		var piece = pieces[i];
		var e = _getExit(roomId, x + piece.x, y + piece.y);
		if (e) {
			return e;
		}
	}
}
before("movePlayer", function () {
	if (enabled) {
		bitsy.getItemIndex = getItemIndexOverride;
		bitsy.getEnding = getEndingOverride;
		bitsy.getExit = getExitOverride;
	}
});
after("movePlayer", function () {
	bitsy.getItemIndex = _getItemIndex;
	bitsy.getEnding = _getEnding;
	bitsy.getExit = _getExit;
	if (enabled) {
		syncPieces();
	}
});


// handle wall/sprite collision
function repeat(fn) {
	var p = bitsy.player();
	var x = p.x;
	var y = p.y;
	var r;
	for (var i = 0; i < pieces.length; ++i) {
		var piece = pieces[i];
		p.x = x + piece.x;
		p.y = y + piece.y;
		r = r || fn();
	}
	p.x = x;
	p.y = y;
	return r;
}
var repeats = [
	'getSpriteLeft',
	'getSpriteRight',
	'getSpriteUp',
	'getSpriteDown',
	'isWallLeft',
	'isWallRight',
	'isWallUp',
	'isWallDown'
];

// prevent player from colliding with their own pieces
function filterPieces(id) {
	for (var i = 0; i < pieces.length; ++i) {
		if (id === pieces[i].spr) {
			return null;
		}
	}
	return id;
}

after('startExportedGame', function () {
	for (var i = 0; i < repeats.length; ++i) {
		var r = repeats[i];
		var _fn = bitsy[r];
		bitsy[r] = function (fn) {
			return enabled ? repeat(fn) : fn();
		}.bind(undefined, _fn);
	}
	var _getSpriteAt = bitsy.getSpriteAt;
	bitsy.getSpriteAt = function () {
		return filterPieces(_getSpriteAt.apply(this, arguments));
	}
});