Common.js

function vec(x = 0, y = 0) {
	return createVector(x, y)
}

function add(a, b) {
	let v = vec()
	v.x = a.x + b.x
	v.y = a.y + b.y
	return v;
}

function sub(a, b) {
	let v = vec()
	v.x = a.x - b.x
	v.y = a.y - b.y
	return v;
}

function mul(a, b) {
	if (!b) b = 0
	let v = vec()
	v.x = a.x * b
	v.y = a.y * b
	return v;
}

function rectContains(x, y, w, h, pt) {
	return x < pt.x && x + w > pt.x
		&& y < pt.y && y + h > pt.y
}

function circleContains(x, y, radius, pt) {
	var diff = sub(vec(x, y), pt)
	return diff.magSq() < radius * radius
}

function outOfBounds(a) {
	return !rectContains(0, 0, width, height, a)
}

function getImageData(image, scale) {
	let canvas = document.createElement("canvas")
	canvas.width = image.width * scale
	canvas.height = image.height * scale
	let ctx = canvas.getContext("2d")
	ctx.scale(scale, scale)
	ctx.drawImage(image, 0, 0)
	return ctx.getImageData(0, 0, canvas.width, canvas.height)
}

function getColor(imageData, x, y, width, imageScale) {
	let pixels = imageData.data
	x = (x / imageScale) | 0
	y = (y / imageScale) | 0
	w = width / imageScale
	let index = (y * w + x) * 4
	return [
		pixels[index],
		pixels[index + 1],
		pixels[index + 2]
	]
}

function xyToIndex(x, y, w) {
	return y * w + x
}