javascript initialistion of objects doing weird

javascript initialistion of objects doing weird - javascript

I am working on a circle packing algorithm in p5.js and vue 3. For some reason it is adding an item to an array that it shouldn't be able to add. I've written some collisions with other objects, and while the program is running it works fine, but when I initialise an object it doesn't seem to care about them. The collisions always return false on initialisation, and even before updating the object again, it says it does collide, but only after adding it to my array. Which is the thing I don't want to be happening, since this clutters my array.
My code:
export function circlePacking(element, imageToShow) {
return function (p) {
const p5Canvas = element;
let circles = [];
let image;
p.preload = function () {
image = p.loadImage(imageToShow);
};
p.setup = function () {
p.colorMode('RGB');
p.disableFriendlyErrors = true;
p.frameRate(60);
this.averageColor = averageColor(p, image);
const canvas = p.createCanvas(p5Canvas.offsetWidth - 1, p5Canvas.offsetHeight - 1, 'P2D');
canvas.parent(p5Canvas);
image.resize(p.width, p.height);
image.loadPixels();
};
p.draw = function () {
if (p5Canvas.offsetWidth - 1 !== p.width || p5Canvas.offsetHeight - 1 !== p.height) {
p.resizeCanvas(p5Canvas.offsetWidth - 1, p5Canvas.offsetHeight - 1);
}
p.background(this.averageColor);
for (let i = 0; i < 5; i++) {
let x = p.round(getRandom(0, image.width));
let y = p.round(getRandom(0, image.height));
let location = (x + y * image.width) * 4;
let color = p.color(image.pixels[location], image.pixels[location + 1], image.pixels[location + 2])
let c = new Circle(x, y, color);
console.log(c);
//here collidesWithCircle is false, even though it should be true
if (!c.collidesWithCircle() && !c.collidesWithWall()) {
circles.push(c);
}
}
circles.forEach(circle => {
circle.draw();
})
circles.forEach(circle => {
circle.checkCollision();
})
};
class Circle {
constructor(x, y, color) {
this.x = x;
this.y = y;
this.color = color;
this.size = 1;
this.growing = true;
this.collidesWall = this.collidesWithWall();
this.collidesCircle = this.collidesWithCircle();
}
draw() {
p.stroke(0);
p.strokeWeight(1);
p.fill(this.color);
p.circle(this.x, this.y, this.size)
if (this.growing) {
this.grow()
}
}
grow() {
this.size += 0.3;
}
checkCollision() {
if (this.growing) {
this.collidesWithCircle();
this.collidesWithWall();
}
}
collidesWithCircle() {
circles.forEach(circle => {
if (p.dist(this.x, this.y, circle.x, circle.y) < (this.size / 2) + (circle.size / 2) && this !== circle) {
this.growing = false;
return true;
}
});
return false;
}
collidesWithWall() {
if (this.x + this.size / 2 > p.width || this.x - this.size / 2 < 0 || this.y + this.size / 2 > p.height || this.y - this.size / 2 < 0) {
this.growing = false;
return true;
}
return false;
}
}
};
}

Related

Clicking Circle Game Javascript

I'm trying to make a simple interactive game where there are circles of different colours moving in the canvas and when the user clicks on the blue circles, it logs the number of clicks on the screen. When clicking circles with any other colour, the animation stops.
I'm very new to javascript but this is what I have for now. I've made a function with random coloured circles and a function with blue circles moving but I'm totally stuck on how to stop the animation when clicking on the function with a random coloured circles and logging the amount of clicks on the blue circles. If someone could help me move forward with it in any way (doesn't have to be the full thing), that would be awesome, thanks.
JS
var canvas;
var ctx;
var w = 1000;
var h = 600;
var colours = ["red", "blue"];
var allCircles = [];
for(var i=0; i<1; i++){
setTimeout(function(){console.log(i)},1000);
}
document.querySelector("#myCanvas").onclick = click;
createData(2);
createDataTwo(20);
setUpCanvas();
animationLoop();
function animationLoop(){
clear();
for(var i = 0; i<allCircles.length; i++){
circle(allCircles[i]);
forward(allCircles[i], 5)
turn(allCircles[i], randn(30));
collisionTestArray(allCircles[i],allCircles)
bounce(allCircles[i]);
}
requestAnimationFrame(animationLoop);
}
function collisionTestArray(o, a){
for(var i=0; i<a.length; i++){
if(o !=a[i]){
collision(o,a[i]);
}
}
}
function collision(o1,o2){
if(o1 && o2){
var differencex = Math.abs(o1.x-o2.x);
var differencey = Math.abs(o1.y-o2.y);
var hdif = Math.sqrt(differencex*differencex+differencey*differencey);
if(hdif<o1.r+o2.r){
if(differencex < differencey){
turn(o1, 180-2*o1.angle);
turn(o2, 180-2*o2.angle);
}else{
turn(o1, 360-2*o1.angle);
turn(o2, 360-2*o2.angle);
}
turn(o1, 180);
turn(o2, 180);
console.log("collision");
};
}
}
function click(event){
clear()
}
function bounce (o){
if(o.x > w || o.x < 0){
turn(o, 180-2*o.angle);
};
if(o.y > h || o.y < 0){
turn(o, 360-2*o.angle);
}
}
function clear(){
ctx.clearRect(0,0,w,h);
}
function stop (){
o1.changex = 0;
o1.changey = 0;
o2.changex = 0;
o2.changey = 0;
}
function circle (o){
var x = o.x;
var y = o.y;
var a = o.angle;
var d = o.d;
ctx.beginPath();
ctx.arc(o.x,o.y,o.r,0,2*Math.PI);
ctx.fillStyle = "hsla("+o.c+",100%,50%, "+o.a+")";
ctx.fill();
o.x = x;
o.y = y;
o.angle = a;
o.d = d;
}
function createData(num){
for(var i=0; i<num; i++){
allCircles.push({
"x": rand(w),
"changex": rand(10),
"y":rand(h),
"changex": rand(10),
"w": randn(w),
"h": randn(h),
"d": 1,
"a": 1,
"angle": 0,
"changle":15,
"c":216,
"r": 50
}
)
}
}
function createDataTwo(num){
for(var i=0; i<num; i++){
allCircles.push({
"x": rand(w),
"changex": rand(10),
"y":rand(h),
"changex": rand(10),
"w": randn(w),
"h": randn(h),
"d": 1,
"a": 1,
"angle": 0,
"changle":15,
"c":rand(90),
"r": 50
}
)
}
}
function turn(o,angle){
if(angle != undefined){
o.changle=angle;
};
o.angle+=o.changle;
}
function forward(o,d){
var changeX;
var changeY;
var oneDegree = Math.PI/180;
if(d != undefined){
o.d = d;
};
changeX= o.d*Math.cos(o.angle*oneDegree);
changeY = o.d*Math.sin(o.angle*oneDegree);
o.x+=changeX;
o.y+=changeY;
}
function randn(r){
var result = Math.random()*r - r/2
return result
}
function randi(r) {
var result = Math.floor(Math.random()*r);
return result
}
function rand(r){
return Math.random()*r
}
function setUpCanvas(){
canvas = document.querySelector("#myCanvas");
ctx = canvas.getContext("2d");
canvas.width = w;
canvas.height = h;
canvas.style.border = "5px solid orange"
ctx.fillStyle = "blue";
ctx.fillRect(0, 0, w, h);
}
console.log("assi4")
HTML
<html>
<head>
<link rel="stylesheet" type="text/css" href="../modules.css">
</head>
<body>
<div id="container">
<h1>Click the Blue Circles Only</h1>
<canvas id = "myCanvas"></canvas>
</div>
<script src="assi5.js"></script>
</body>
</html>
CSS
#container {
margin: auto;
width: 75%;
text-align: center;
}

You can use cancelAnimationFrame to stop the animation when a non-blue circle is clicked
You need to pass it a reference to the frame ID returned from requestAnimationFrame for it to work.
In order to tell if a circle was clicked, you need to check the coordinates of each circle against the coordinates of the click.
I have an example below if you had your blue circles in an array "blue", and other circles in array "other", the ID returned by requestAnimationFrame as "frame".
The check function returns the number of blue circles hit (the points scored) and if any other circles were hit, it stops the animation.
getCoords returns the coordinates of the click on the canvas from the click event.
canvas.addEventListener('click', event=>{
points += check(getCoords(event), blue, other, frame);
document.getElementById('points').textContent = points;
})
function check({x, y}, blue, other, frame) {
other.filter(circle=>circle.isWithin(x, y))
.length && cancelAnimationFrame(frame); // This is where animation stops
return blue.filter(circle=>circle.isWithin(x, y)).length;
}
function getCoords(event) {
const canvas = event.target;
const rect = canvas.getBoundingClientRect()
const x = event.clientX - rect.left;
const y = event.clientY - rect.top;
return { x, y };
}
I have an example that works below where I changed the circles to the result of a function rather than an inline object, and moved the functions you use on them into their own class. You don't have to do this, but I find it a lot easier to understand.
function main() {
const canvas = document.getElementById('canvas');
const context = canvas.getContext("2d");
const clear = () => context.clearRect(0, 0, canvas.width, canvas.height);
const blue = new Array(2).fill().map(() => new Circle(context, 216));
const other = new Array(10).fill().map(() => new Circle(context));
let circles = [...blue, ...other];
let frame = 0;
let points = 0;
// Move the circle a bit and check if it needs to bounce
function update(circle) {
circle.forward(1)
circle.turn(30, true)
circle.collisionTestArray(circles)
circle.bounce();
}
// Main game loop, clear canvas, update circle positions, draw circles
function loop() {
clear();
circles.filter(circle => circle.free).forEach(update);
circles.forEach(circle => circle.draw());
frame = requestAnimationFrame(loop);
}
loop();
canvas.addEventListener('click', event => {
points += check(getCoords(event), blue, other, frame, circles);
document.getElementById('points').textContent = points;
})
}
function check({ x, y }, blue, other, frame) {
other.filter(circle => circle.isWithin(x, y))
// .map(circle=>circle.toggle())
.length && cancelAnimationFrame(frame); // This is where animation stops
return blue.filter(circle => circle.isWithin(x, y)).length;
}
function getCoords(event) {
const canvas = event.target;
const rect = canvas.getBoundingClientRect()
const x = event.clientX - rect.left;
const y = event.clientY - rect.top;
return { x, y };
}
main();
function Circle(context, c) {
const randn = r => rand(r) - r / 2;
const randi = r => Math.floor(randi(r));
const rand = r => Math.random() * r;
// These are for easily stopping and starting a circle;
this.free = true;
this.stop = () => this.free = false;
this.release = () => this.free = true;
this.toggle = () => this.free = !this.free;
const {
width,
height
} = context.canvas;
// These are the same properties you were using in your code
this.x = rand(width);
this.changex = rand(10);
this.y = rand(height);
this.changey = rand(10);
this.w = randn(width);
this.h = randn(height);
this.d = 1;
this.a = 1;
this.angle = 0;
this.changle = 15;
this.c = c || rand(90); // This is the only difference between blue and other circles
this.r = 50;
// These next functions you had in your code, I just moved them into the circle definition
this.draw = () => {
const { x, y, r, c } = this;
context.beginPath();
context.arc(x, y, r, 0, 2 * Math.PI);
context.fillStyle = "hsla(" + c + ",100%,50%, 1)";
context.fill();
}
this.bounce = () => {
const { x, y, angle } = this;
if (x > width || x < 0) {
this.turn(180 - 2 * angle);
}
if (y > height || y < 0) {
this.turn(360 - 2 * angle);
}
}
this.turn = (angle, random = false) => {
this.changle = random ? randn(angle) : angle;
this.angle += this.changle;
}
this.forward = d => {
this.d = d;
this.x += this.d * Math.cos(this.angle * Math.PI / 180);
this.y += this.d * Math.sin(this.angle * Math.PI / 180);
}
this.collisionTestArray = a => a
.filter(circle => circle != this)
.forEach(circle => this.collision(circle));
this.collision = circle => {
var differencex = Math.abs(this.x - circle.x);
var differencey = Math.abs(this.y - circle.y);
var hdif = Math.sqrt(differencex ** 2 + differencey ** 2);
if (hdif < this.r + circle.r) {
if (differencex < differencey) {
this.turn(180 - 2 * this.angle);
circle.turn(180 - 2 * circle.angle);
} else {
this.turn(360 - 2 * this.angle);
circle.turn(360 - 2 * circle.angle);
}
this.turn(180);
circle.turn(180);
}
}
// These 2 functions I added to check if the circle was clicked
this.distanceFrom = (x, y) => Math.sqrt((this.x - x) ** 2 + (this.y - y) ** 2);
this.isWithin = (x, y) => this.r > this.distanceFrom(x, y);
}
#canvas {
border: 5px solid orange;
}
#container {
margin: auto;
width: 75%;
text-align: center;
}
<div id="container">
<h1>Click the Blue Circles Only</h1>
<canvas id="canvas" width="1000" height="600"></canvas>
<p>
Points: <span id="points">0</span>
</p>
</div>

using OOP is better in this situation and will save you a lot of time
I have written the OOP version of your game, I wrote it in harry so you may find some bugs but it is good as a starting point
const canvas = document.querySelector("canvas")
const ctx = canvas.getContext("2d")
let h = canvas.height = 600
let w = canvas.width = 800
const numberOfCircles = 20
let circles = []
// running gameover
let gameStatus = "running"
let score = 0
canvas.addEventListener("click", (e) => {
if(gameStatus === "gameOver") {
document.location.reload()
return;
}
const mouse = {x: e.offsetX, y: e.offsetY}
for(let circle of circles) {
if(distance(mouse, circle) <= circle.radius) {
if(circle.color == "blue") {
gameStatus = "running"
score += 1
} else {
gameStatus = "gameOver"
}
}
}
})
class Circle {
constructor(x, y, color, angle) {
this.x = x
this.y = y
this.color = color
this.radius = 15
this.angle = angle
this.speed = 3
}
draw(ctx) {
ctx.beginPath();
ctx.fillStyle = this.color;
ctx.arc(this.x, this.y, this.radius, 0, Math.PI * 2);
ctx.fill();
}
move(circles) {
this.check(circles)
this.x += Math.cos(this.angle) * this.speed
this.y += Math.sin(this.angle) * this.speed
}
check(circles) {
if(this.x + this.radius > w || this.x - this.radius < 0) this.angle += Math.PI
if(this.y + this.radius > h || this.y - this.radius < 0) this.angle += Math.PI
for(let circle of circles) {
if(circle === this) continue
if(distance(this, circle) <= this.radius + circle.radius) {
// invert angles or any other effect
// there are much better soultion for resolving colliusions
circle.angle += Math.PI / 2
this.angle += Math.PI / 2
}
}
}
}
}
setUp()
gameLoop()
function gameLoop() {
ctx.clearRect(0,0,w,h)
if(gameStatus === "gameOver") {
ctx.font = "30px Comic"
ctx.fillText("Game Over", w/2 - 150, h/2 - 100)
ctx.fillText("you have scored : " + score, w/2 - 150, h/2)
return;
}
ctx.font = "30px Comic"
ctx.fillText("score : " + score, 20, 30)
for (let i = 0; i < circles.length; i++) {
const cirlce = circles[i]
cirlce.draw(ctx)
cirlce.move(circles)
}
requestAnimationFrame(gameLoop)
}
function random(to, from = 0) {
return Math.floor(Math.random() * (to - from) + from)
}
function setUp() {
gameStatus = "running"
score = 0
circles = []
for (var i = 0; i < numberOfCircles; i++) {
const randomAngle = random(360) * Math.PI / 180
circles.push(new Circle(random(w, 20), random(h, 20), randomColor(), randomAngle))
}
}
function randomColor() {
const factor = random(10)
if(factor < 3) return "blue"
return `rgb(${random(255)}, ${random(255)}, ${random(100)})`
}
function distance(obj1, obj2) {
const xDiff = obj1.x - obj2.x
const yDiff = obj1.y - obj2.y
return Math.sqrt(Math.pow(xDiff, 2) + Math.pow(yDiff, 2))
}

How to draw a rubberband or lasso to make a selection in word selection game

I am trying to put a word search game on my web page.
I see here is a beautiful example: Embed a Word Search in Your Site
I want to make similar gui, so that when the user selects the word letters from the grid by dragging mouse, it will draw a red elastic rubber band around the letters selected.
How do they do it on their web page? I tried to "inspect" the html after the band is drawn, however did not see any element added.
Can somebody give me any clue?

Here is a JS example
class App {
constructor(div) {
this.div = div;
this.canvas = document.getElementById("canvas");
this.ctx = canvas.getContext('2d');
this.dirty = true;
this.prev = +new Date();
this.resize();
window.addEventListener('resize', () => this.resize(), false);
this.canvas.addEventListener("mousedown", (event) => {
this.touchdown(...App.getmousePos(event));
event.preventDefault();
});
this.canvas.addEventListener("mousemove", (event) => {
this.touchmove(...App.getmousePos(event));
event.preventDefault();
});
this.canvas.addEventListener("mouseup", (event) => {
this.touchup(...App.getmousePos(event));
event.preventDefault();
});
this.canvas.addEventListener("touchstart", (event) => {
this.touchdown(...App.getmousePos(event));
event.preventDefault();
});
this.canvas.addEventListener("touchmove", (event) => {
this.touchmove(App.getmousePos(event));
event.preventDefault();
});
this.canvas.addEventListener("touchend", (event) => {
this.touchup(App.getmousePos(event));
event.preventDefault();
});
}
resize() {
this.canvas.width = this.div.clientWidth;
this.canvas.height = this.div.clientWidth;
this.draw();
}
loop() {
let now = +new Date();
let dt = now - this.prev;
this.prev = now;
this.update()
if (this.dirty)
this.draw();
window.requestAnimationFrame(() => this.loop());
}
update(dt) {}
draw() {
this.ctx.clearRect(0, 0, canvas.width, canvas.height);
this.ctx.rect(0, 0, 100, 100);
this.ctx.fill();
}
touchdown(x, y) { console.log("down", x, y); }
touchmove(x, y) {}
touchup(x, y) {}
static getmousePos(event) {
if (event.changedTouches) {
return [event.changedTouches[0].pageX, event.changedTouches[0].pageY];
}
else {
var rect = event.target.getBoundingClientRect();
return [event.clientX- rect.left, event.clientY - rect.top];
}
}
}
class Vector {
constructor(x, y) {
this.x = x;
this.y = y;
}
add(v_x, y) {
if (y != undefined) {
return new Vector(this.x + v_x, this.y + y);
}
else {
return new Vector(this.x + v_x.x, this.y + v_x.y);
}
}
sub(v_x, y) {
if (y != undefined) {
return new Vector(this.x - v_x, this.y - y);
}
else {
return new Vector(this.x - v_x.x, this.y - v_x.y);
}
}
mul(s) {
return new Vector(this.x * s, this.y * s);
}
get slength() {
return this.x * this.x + this.y * this.y;
}
get length() {
return Math.sqrt(this.x * this.x + this.y * this.y);
}
get angle() {
return Math.atan2(this.y, this.x);
}
}
class Grid {
constructor(width, height, data) {
this.width = width;
this.height = height;
this.data = data || new Array(width*height).fill("_");
}
get length() {
return this.width*this.height;
}
get(x_pos, y) {
if (y != undefined)
return this.data[x_pos+y*this.width];
else
return this.data[x_pos];
}
set(value, x_pos, y) {
if (y != undefined)
this.data[x_pos+y*this.width] = value;
else
this.data[x_pos] = value;
}
clone() {
return new Grid(this.width, this.height, this.data.slice());
}
finalize() {
this.data = this.data.map(v => v == "_" ? String.fromCharCode(Math.floor(Math.random() * 26) + 97) : v);
}
print() {
for (let i = 0; i < this.height; i++)
console.log(this.data.slice(i*this.width, (i+1)*this.width).join(","));
}
}
class Puzzle {
constructor(width, height, words, directions) {
this.grid = new Grid(width, height);
this.words = words;
this.placeWords(words, directions);
}
placeWords(words, directions) {
const range = (N) => Array.from({length: N}, (v, k) => k);
const shuffle = (array) => {
for (let i = array.length - 1; i > 0; i--) {
let j = Math.floor(Math.random() * (i + 1));
[array[i], array[j]] = [array[j], array[i]];
}
return array;
}
words = words.slice();
let positions = range(this.grid.length);
let stack = [ {
grid: this.grid,
word: words.shift(),
directions: shuffle(directions.slice()),
positions: shuffle(positions.slice()) } ];
while (true) {
let current = stack[stack.length-1];
if (!current)
throw Error("impossible");
let dir = current.directions.pop();
if (!dir) {
current.positions.pop();
current.directions = shuffle(directions.slice());
dir = current.directions.pop();
}
if (current.positions.length <= 0) {
words.unshift(current.word);
stack.pop();
}
else {
let pos = current.positions[current.positions.length-1];
let grid = this.placeWord(current.grid, current.word, pos, dir);
if (grid) {
if (words.length > 0) {
stack.push({grid: grid,
word: words.shift(),
directions: shuffle(directions.slice()),
positions: shuffle(positions.slice())});
}
else {
grid.finalize();
this.grid = grid;
break;
}
}
}
}
}
placeWord(grid, word, position, direction) {
let copy = grid.clone();
position = new Vector(position % grid.width, Math.floor(position / grid.width));
let letters = [...word];
while (0 <= position.x && position.x < grid.width && 0 <= position.y && position.y < grid.height) {
if (letters.length <= 0)
break;
let letter = letters.shift();
if (copy.get(position.x, position.y) == "_" || copy.get(position.x, position.y) == letter) {
copy.set(letter, position.x, position.y);
position = position.add(direction);
}
else {
return null;
}
}
if (letters.length > 0)
return null;
else
return copy;
}
wordAt(position, direction, length) {
let word = new Array(length);
for (let i = 0; i < length; i++) {
word[i] = this.grid.get(position.x, position.y);
position = position.add(direction);
}
return word.join("");
}
print() {
this.grid.print();
}
}
class Selection {
constructor(position, fill=false) {
this.position = position;
this._fill = fill;
this.direction = new Vector(1, 0);
this.length = 0;
this.flength = 0;
}
clone() {
return new Selection(this.position).to(this.position.add(this.direction.mul(this.length)));
}
to(position) {
let direction = position.sub(this.position);
if (Math.abs(direction.y) == 0) {
this.direction = new Vector(direction.x >= 0 ? 1 : -1, 0);
this.length = direction.x * this.direction.x;
}
else if (Math.abs(direction.x) == 0) {
this.direction = new Vector(0, direction.y >= 0 ? 1 : -1);
this.length = direction.y * this.direction.y;
}
else {
this.direction = new Vector(direction.x >= 0 ? 1 : -1, direction.y >= 0 ? 1 : -1);
this.length = direction.x * this.direction.x;
}
this.flength = direction.length;
return this;
}
fill(fill=true) {
this._fill = fill;
return this;
}
draw(ctx, wsize, hsize) {
let pos = this.position.mul(wsize);
let length = wsize * (this.flength+1);
let angle = this.direction.angle;
//console.log(this.x, this.y, x, y, length, angle, this.dx, this.dy);
ctx.save();
ctx.strokeStyle = "black";
ctx.fillStyle = "yellow";
ctx.translate(pos.x+hsize*0.5, pos.y+hsize*0.5);
ctx.rotate(angle);
this.drawHighlight(ctx, -hsize*0.5, -hsize*0.5, length, hsize, hsize*0.5, this._fill, true);
ctx.restore();
}
drawHighlight(ctx, x, y, width, height, radius=20, fill=true, stroke=false) {
ctx.beginPath();
ctx.moveTo(x + radius, y);
ctx.lineTo(x + width - radius, y);
ctx.quadraticCurveTo(x + width, y, x + width, y + radius);
ctx.lineTo(x + width, y + height - radius);
ctx.quadraticCurveTo(x + width, y + height, x + width - radius, y + height);
ctx.lineTo(x + radius, y + height);
ctx.quadraticCurveTo(x, y + height, x, y + height - radius);
ctx.lineTo(x, y + radius);
ctx.quadraticCurveTo(x, y, x + radius, y);
ctx.closePath();
if (fill) ctx.fill();
if (stroke) ctx.stroke();
}
}
class PuzzleApp extends App {
constructor(div, puzzle) {
super(div);
this.puzzle = puzzle;
this.renderList(document.getElementById("list"));
this.selections = new Array();
this.loop();
}
renderList(parent) {
this.puzzle.words.forEach(word => {
let li = document.createElement("li");
let text = document.createTextNode(word);
li.appendChild(text);
parent.appendChild(li);
});
}
gridSize() {
let wsize = Math.floor(this.canvas.width/this.puzzle.grid.width);
let hsize = Math.floor(this.canvas.width/this.puzzle.grid.height);
return [wsize, hsize];
}
clientToGrid(x, y) {
let [wsize, hsize] = this.gridSize();
x = Math.floor(x / wsize);
y = Math.floor(y / hsize);
return [x, y];
}
draw() {
if (!this.puzzle)
return;
this.ctx.clearRect(0, 0, canvas.width, canvas.height);
let [wsize, hsize] = this.gridSize();
this.selections.forEach(s => s.draw(this.ctx, wsize, hsize));
if (this.selection)
this.selection.draw(this.ctx, wsize, hsize);
let x = 0;
let y = 0;
this.ctx.fillStyle = "black";
this.ctx.font = (wsize * 0.5) + 'px sans-serif';
this.ctx.textAlign = "center";
this.ctx.textBaseline = "middle";
for (let j = 0; j < this.puzzle.grid.height; j++) {
for (let i = 0; i < this.puzzle.grid.width; i++) {
let letter = this.puzzle.grid.get(i, j);
this.ctx.fillText(letter, x+wsize * 0.5, y+wsize * 0.5);
x += wsize;
}
x = 0;
y += wsize;
}
}
touchdown(x, y) {
[x, y] = this.clientToGrid(x, y);
this.selection = new Selection(new Vector(x, y));
this.dirty = true;
}
touchmove(x, y) {
if (!this.selection)
return;
[x, y] = this.clientToGrid(x, y);
this.selection.to(new Vector(x, y));
}
touchup(x, y) {
if (!this.selection)
return;
let word = this.puzzle.wordAt(this.selection.position, this.selection.direction, this.selection.length+1);
console.log(word);
if (word) {
let list = document.getElementById("list");
let elements = list.getElementsByTagName("li");
Array.prototype.some.call(elements, li => {
if (li.innerText == word) {
li.classList.add("found");
this.selections.push(this.selection.clone().fill());
return true;
}
return false;
});
}
this.selection = null;
}
}
let app = null;
document.addEventListener("DOMContentLoaded", function(event) {
const wordLists = [
["pear", "apple", "banana", "peach", "kiwi", "prune", "persimon"]
]
const pick = (array) => array[Math.floor(Math.random() * (array.length))];
let params = (new URL(document.location)).searchParams;
let directions = [new Vector(1,0), new Vector(0,1)];
if (params.get("diagonal")) {
directions.push(new Vector(1,1));
}
if (params.get("backwards")) {
directions.push(new Vector(-1,0));
directions.push(new Vector(0,-1));
if (params.get("diagonal")) {
directions.push(new Vector(-1,-1));
}
}
let puzzle = new Puzzle(8, 8, pick(wordLists), directions);
puzzle.print();
app = new PuzzleApp(document.getElementById("canvasContainer"), puzzle);
});
html, body {
width: 100%;
height: 100%;
margin: 0px;
}
ul {
display: inline-block;
font-size: 7vmin;
padding-left: 14vmin;
}
li.found {
text-decoration: line-through;
}
div#canvasContainer {
width: 100%;
display: inline-block;
}
#media (min-aspect-ratio: 1/1) {
ul {
font-size: 4vmin;
padding-left: 7vmin;
}
div#canvasContainer {
width: 50%;
}
}
<div id="canvasContainer"><canvas id="canvas" width="320" height="320"></canvas></div>
<ul id="list"></ul>
I'll let you figure out how to change the thickness and color of the rubber band.

The red band is an svg. It doesn't get added when you click, but rather it gets redrawn.

I have inspected the referenced website and it seems like they draw rubber band thing in SVG. If you inspect this SVG tag while drawing:
you will notice it shows some updates.
You can use same SVG methodology. Or Another way is to use an absolute positioned div and update top, left css values based on mousedown, width based on mousemove event.

I have seen "what" they have done.
They have created an svg element. This svg sits exactly above and covers the entire table that contains the grid with letters. When the user clicks any letter and starts drag, they add a rectangle to the svg. Depending on how the cursor will move they do the angle transform to the rectangle. If the word is selected correctly, the rectangle survives; else, it is removed.
I need to find out now, "how" part of it.
Thanks to all for a very quick response.

collision detection between moving objects

If all my NPCs are stationary, the collision detection works as expected. However, when they are moving, the objects move through each other. I don't understand the difference between the moving object and the stationary object. I am tracking the hitboxes of all the NPCs and I'm pretty sure they're accurate. Maybe someone has some insight. Thanks in advance.
function Hero(map, x, y, facing, image, chars, type) {
this.map = map;
this.x = x;
this.y = y;
this.width = map.tsize;
this.height = map.tsize;
this.chars = chars
// facing = R=0 U=1 L=2 D=3
this.facing = facing
this.image = Loader.getImage(image)
this.type = type
}
Hero.prototype.hitBox = function(type){
if (this.type === "hero"){
return {
left: this.x - this.width/2,
right: this.x + this.width/2 -1,
top: this.y + this.height/2,
bottom: this.y + this.height -1
}
} else if (this.type === "npc") {
return {
left: this.x - this.width/2,
right: this.x + this.width/2 -1,
top: this.y - this.height/2,
bottom: this.y + this.height -1
}
}
};
Hero.SPEED = 256; // pixels per second
Hero.prototype.move = function (delta, dirx, diry) {
// move hero
this.x += dirx * Hero.SPEED * delta;
this.y += diry * Hero.SPEED * delta;
// clamp values
var maxX = (this.map.cols-2) * this.map.tsize;
var maxY = (this.map.rows-2) * this.map.tsize;
this.x = Math.max(0, Math.min(this.x, maxX));
this.y = Math.max(0, Math.min(this.y, maxY));
// check if we walked into a non-walkable tile
this._collide(delta, dirx, diry);
};
Hero.prototype.objCollision = function (obj){
let objHitBox = obj.hitBox()
let heroHitBox = this.hitBox()
if (objHitBox.left < heroHitBox.right&&
objHitBox.right > heroHitBox.left &&
objHitBox.top < heroHitBox.bottom &&
objHitBox.bottom > heroHitBox.top) {
return true
} else {
return false
}
}
Hero.prototype._collide = function (delta, dirx, diry) {
let row, col;
// check for collisions on sprite sides
let collision =
this.map.isSolidTileAtXY(this.hitBox()["left"], this.hitBox()["top"]) ||
this.map.isSolidTileAtXY(this.hitBox()["right"], this.hitBox()["top"]) ||
this.map.isSolidTileAtXY(this.hitBox()["right"], this.hitBox()["bottom"]) ||
this.map.isSolidTileAtXY(this.hitBox()["left"], this.hitBox()["bottom"])
//loop through all hexes with NPCs
let objCollision = this.chars.all.reduce(function (res, obj) {
let tmp;
if (obj !== this) {
tmp = this.objCollision(obj)
}
else {
return false
}
return res || tmp;
}.bind(this), false)
if (!collision && !objCollision) { return; }
if (diry > 0) {
row = this.map.getRow(this.hitBox()["bottom"]);
this.y = -Hero.SPEED*delta + this.y
}
else if (diry < 0) {
row = this.map.getRow(this.hitBox()["top"]);
this.y = Hero.SPEED*delta + this.y
}
else if (dirx > 0) {
col = this.map.getCol(this.hitBox()["right"]);
this.x = -Hero.SPEED*delta+ this.x;
}
else if (dirx < 0) {
col = this.map.getCol(this.hitBox()["left"]);
this.x = Hero.SPEED*delta + this.x;
}
};
aiMove(delta) {
switch(this.facing){
case 0:
this.dirx= 1
this.diry= 0
break;
case 1:
this.dirx= 0
this.diry= -1
break;
case 2:
this.dirx= -1
this.diry= 0
break;
case 3:
this.dirx= 0
this.diry= 1
break;
}
if (!this.waiting && this.moveTimer < 1) {
//Random direction
this.facing = Math.floor(Math.random() * Math.floor(4))
//random time
this.restStepTimer();
} else if (!this.waiting && this.moveTimer > 0) {
//Move to preset direction
this.move(delta, this.dirx, this.diry)
//subtract timer
this.moveTimer--;
//if timer is empty, switch to waiting and reset timer.
if (this.moveTimer <= 0) {
this.waiting = true;
this.restStepTimer();
}
} else if (this.waiting && this.moveTimer > 0) {
//while waiting, we lower the timer.
this.moveTimer--;
//when the timer runs out, we flip the flag back to not waiting and start again.
if (this.moveTimer <= 0) {
this.waiting = false;
}
}
};
restStepTimer() {
this.moveTimer = Math.floor(Math.random() * 50 + 20);
};
};

Accessibility of functions in javascript

This is a question from javascript.
if (game.ship.livesPool.getPool[0].getDamaged())
I got an error on this getDamaged() function as undefined inside another function.
game = new Game();
game is defined outside this function as a global variable.
this.ship = new Ship();
ship is defined inside Game class.
this.livesPool = new Pool();
var pool = [];
this.getPool = function(){
return pool;
}
livesPool is defined inside Pool class. pool is an array defined in Pool class.
getPool function will return this array.
pool[i] = new Lives();
each of the pool[i] will be assigned Lives object in Pool class.
this.getDamaged = function(){
return this.damaged;
}
getDamaged() function is defined this way inside Lives class.
Why does it show me that this function is undefined?
Game class
function Game() {
this.init = function () {
// Obtain the canvas from HTML
this.bgCanvas = document.getElementById('background');
this.shipCanvas = document.getElementById('ship');
this.mainCanvas = document.getElementById('main');
// Load the context
/* Just one of them passing to conditional statement is enough to test
* the availability
*/
if (this.bgCanvas.getContext) {
this.bgContext = this.bgCanvas.getContext('2d');
this.shipContext = this.shipCanvas.getContext('2d');
this.mainContext = this.mainCanvas.getContext('2d');
Background.prototype.context = this.bgContext;
Background.prototype.canvasHeight = this.bgCanvas.height;
Background.prototype.canvasWidth = this.bgCanvas.width;
Ship.prototype.context = this.shipContext;
Ship.prototype.canvasHeight = this.shipCanvas.height;
Ship.prototype.canvasWidth = this.shipCanvas.width;
Lives.prototype.context = this.shipContext;
Lives.prototype.canvasHeight = this.shipCanvas.height;
Lives.prototype.canvasWidth = this.shipCanvas.width;
Bullet.prototype.context = this.mainContext;
Bullet.prototype.canvasHeight = this.mainCanvas.height;
Bullet.prototype.canvasWidth = this.mainCanvas.width;
Bullet.prototype.bossContext = this.shipContext;
Enemy.prototype.context = this.mainContext;
Enemy.prototype.canvasHeight = this.mainCanvas.height;
Enemy.prototype.canvasWidth = this.mainCanvas.width;
Boss.prototype.context = this.shipContext;
Boss.prototype.canvasHeight = this.shipCanvas.height;
Boss.prototype.canvasWidth = this.shipCanvas.width;
// Define background in the game
this.background = new Background();
this.background.init(0, 0, imageRepository.background.width, imageRepository.background.height);
// Define ship in the game
this.ship = new Ship();
var shipStartX = this.shipCanvas.width / 2 - imageRepository.ship.width / 2;
var shipStartY = this.shipCanvas.height / 4 * 3 + imageRepository.ship.height / 2;
this.ship.init(shipStartX, shipStartY, imageRepository.ship.width, imageRepository.ship.height);
this.ship.type = "ship";
this.ship.hasExplored = false;
// Define enemy pools in the game
this.enemyPool = new Pool(10);
this.enemyPool.init("enemy");
this.boss = new Boss();
return true;
}
else {
return false;
}
};
this.runGame = function () {
this.ship.draw();
animate();
};
this.restart = function () {
this.bgContext.clearRect(0, 0, this.bgCanvas.width, this.bgCanvas.height);
this.mainContext.clearRect(0, 0, this.mainCanvas.width, this.mainCanvas.height);
this.shipContext.clearRect(0, 0, this.shipCanvas.width, this.shipCanvas.height);
this.enemyPool.init("enemy");
var shipStartX = this.shipCanvas.width / 2 - imageRepository.ship.width / 2;
var shipStartY = this.shipCanvas.height / 4 * 3 + imageRepository.ship.height / 2;
this.ship.x = shipStartX;
this.ship.y = shipStartY;
this.ship.hasExplored = false;
this.ship.bulletPool.init("bullet");
score = 0;
displayedScore = 0;
bossExist = false;
this.boss.life = 100;
this.boss.bulletPool.init("boss_bullet");
this.boss.fireRate = 0;
while(this.ship.livesPool.getSize() < 3){
this.ship.livesPool.increaseLives();
}
document.getElementById('game-over').style.display = "none";
this.runGame();
};
this.start = function () {
gameStarted = true;
document.getElementById('main-menu').style.display = 'none';
document.getElementById('score-board').style.display = 'block';
};
this.backHome = function () {
gameStarted = false;
document.getElementById('game-over').style.display = 'none';
document.getElementById('score-board').style.display = 'none';
document.getElementById('main-menu').style.display = 'block';
this.restart();
};
}
Ship class.
function Ship() {
this.speed = 5;
this.bulletPool = new Pool(maxNumOfBullets);
this.bulletPool.init("bullet");
this.bulletSoundPool = new SoundPool(maxNumOfBullets);
this.bulletSoundPool.init("bullet");
this.livesPool = new Pool(3);
this.livesPool.init("lives");
this.hasExplored = false;
this.life = 3;
var fireRate = 15;
var counter = 0;
this.draw = function () {
if (this.livesPool.getSize() <= 0) {
this.context.clearRect(this.x, this.y, this.width, this.height);
}
else {
this.context.drawImage(imageRepository.ship, this.x, this.y);
}
}
this.move = function () {
counter++;
// Determine if the action is move action
if (KEY_STATUS.left || KEY_STATUS.right ||
KEY_STATUS.down || KEY_STATUS.up) {
// The ship moved, so erase it's current image so it can
// be redrawn in it's new location
this.context.clearRect(this.x, this.y, this.width, this.height);
// Update x and y according to the direction to move and
// redraw the ship. Change the else if's to if statements
// to have diagonal movement.
if (KEY_STATUS.left) {
this.x -= this.speed
if (this.x <= 0) // Keep player within the screen
this.x = 0;
} else if (KEY_STATUS.right) {
this.x += this.speed
if (this.x >= this.canvasWidth - this.width)
this.x = this.canvasWidth - this.width;
} else if (KEY_STATUS.up) {
this.y -= this.speed
if (this.y <= this.canvasHeight / 4 * 3)
this.y = this.canvasHeight / 4 * 3;
} else if (KEY_STATUS.down) {
this.y += this.speed
if (this.y >= this.canvasHeight - this.height)
this.y = this.canvasHeight - this.height;
}
}
this.draw();
if (KEY_STATUS.space && counter >= fireRate) {
this.fire();
counter = 0;
}
};
this.fire = function () {
this.bulletPool.getTwo(this.x + imageRepository.ship.width / 10, this.y, 3);
this.bulletSoundPool.get();
};
}
Pool class.
function Pool(maxSize) {
var size = maxSize;
var pool = [];
var type = "";
// This design enables us to not need to create an object each loop
this.init = function (obj) {
if (obj === "bullet") {
type = "bullet";
for (var i = 0; i < size; i++) {
var bullet = new Bullet("bullet");
bullet.init(0, 0, imageRepository.bullet.width, imageRepository.bullet.height);
bullet.collidableWith = "enemy";
bullet.type = "bullet";
pool[i] = bullet;
}
}
else if (obj === "enemy") {
type = "enemy";
for (var i = 0; i < size; i++) {
var enemy = null;
var rand = Math.floor(Math.random() * 10);
if (rand < 8) {
enemy = new Enemy("enemy", 0, 10);
enemy.init(0, 0, imageRepository.enemy.width, imageRepository.enemy.height);
}
else {
enemy = new Enemy("enemy2", 2, 15);
enemy.init(0, 0, imageRepository.enemy2.width, imageRepository.enemy2.height);
}
enemy.collidableWith = "ship";
enemy.type = "enemy";
pool[i] = enemy;
}
}
else if (obj === "boss_bullet") {
type = "boss_bullet";
for (var i = 0; i < size; i++) {
var bullet = new Bullet("boss_bullet");
bullet.init(0, 0, imageRepository.boss_bullet.width, imageRepository.boss_bullet.height);
bullet.collidableWith = "ship";
bullet.type = "bullet";
pool[i] = bullet;
}
}
else if (obj === "lives") {
type = "lives";
for (var i = 0; i < size; i++) {
var lives = new Lives();
lives.init(imageRepository.background.width - ((i + 1) * imageRepository.lives.width) - 10,
imageRepository.background.height - imageRepository.lives.height - 10,
imageRepository.lives.width, imageRepository.lives.height);
pool[i] = lives;
}
}
};
// Return pool attribute for usage in checking collision
this.getPool = function () {
var res = [];
for (var i = 0; i < pool.length; i++) {
if (pool[i].alive) {
res.push(pool[i]);
}
}
return res;
};
this.get = function (x, y, speed) {
if (pool[size - 1] instanceof Bullet) {
if (!pool[size - 1].alive) {
pool[size - 1].spawn(x, y, speed);
pool.unshift(pool.pop());
}
}
else if (pool[size - 1] instanceof Enemy) {
if (!pool[size - 1].alive) {
if (!(pool[0].alive && pool[0].y <= pool[0].height)) {
pool[size - 1].spawn(x, y, speed);
pool.unshift(pool.pop());
}
}
}
};
this.getTwo = function (x, y, speed) {
if (type === "bullet") {
if (!pool[size - 1].alive && !pool[size - 2].alive) {
this.get(x, y, speed);
this.get(x + (imageRepository.ship.width * 8) / 10
- imageRepository.bullet.width, y, speed);
}
}
else if (type === "boss_bullet") {
if (!pool[size - 1].alive && !pool[size - 2].alive) {
this.get(x, y, speed);
// This will have the center of boss as the center between two bullets
// x + 2 * (imageRepository.boss.width / 2 - x) - imageRepository.boss_bullet.width
this.get(x + imageRepository.boss.width * 3 / 5 - imageRepository.boss_bullet.width,
y, speed);
console.log(x);
console.log(x + imageRepository.boss.width * 3 / 5 - imageRepository.boss_bullet.width);
}
}
};
this.animate = function () {
for (var i = 0; i < size; i++) {
if (pool[i].alive) {
if (pool[i].draw()) {
pool[i].clear();
pool.push((pool.splice(i, 1))[0]);
}
}
else
break;
}
};
this.getSize = function () {
return size;
};
this.setSize = function (input) {
size = input;
};
this.decreaseLives = function () {
if (size >= 1) {
if (pool[size - 1] instanceof Lives) {
pool[size - 1].setDamaged(true);
size--;
}
}
};
this.increaseLives = function(){
if (pool[size - 1] instanceof Lives){
pool[size - 1].setDamaged(true);
size++;
}
};
}
Lives class.
function Lives() {
this.alive = true;
this.damaged = false;
this.draw = function () {
this.context.clearRect(this.x, this.y, this.width, this.height);
this.context.drawImage(imageRepository.lives, this.x, this.y);
if (this.damaged)
return true;
}
this.clear = function () {
alive = false;
this.x = -1 * this.width;
this.y = -1 * this.height;
}
this.getDamaged = function(){
return this.damaged;
}
this.setDamaged = function(input){
this.damaged = input;
}
}

getPool is a function, you need to call it:
if (game.ship.livesPool.getPool()[0].getDamaged())
// ^^

Cannot read property 'x' of undefined JavaScript

I'm getting an error:
Uncaught TypeError: Cannot read property 'x' of undefined
I'm trying to make an object move, however, I'm getting this issue when trying to use Vector2. Here is my code:
Player.js
var bullets = [];
var LEFT = 0;
var RIGHT = 1;
var UP = 2;
var DOWN = 3;
var Player = function(){
this.sprite = new Sprite("playerplaceholder.png");
this.sprite.buildAnimation(1, 1, 32, 32, -1, [0]);
this.sprite.setAnimationOffset(0, 0, 0);
this.sprite.setLoop(0, false);
this.position = new Vector2();
this.position.set(200, 200);
this.width = 48
this.height = 48
this.velocity = new Vector2();
this.moveVector = new Vector2();
this.moveVector.set(this.position.x, this.position.y);
};
Player.prototype.update = function(deltaTime)
{
this.sprite.update(deltaTime);
if((keyboard.isKeyDown(keyboard.KEY_LEFT)) != (keyboard.isKeyDown(keyboard.KEY_RIGHT)))
{
if(keyboard.isKeyDown(keyboard.KEY_RIGHT))
{
Player.moveVector.x += 1;
}
else
{
Player.moveVector.x += -1;
}
}
if((keyboard.isKeyDown(keyboard.KEY_UP)) != (keyboard.isKeyDown(keyboard.KEY_UP)))
{
if(keyboard.isKeyDown(keyboard.KEY_DOWN))
{
Player.moveVector += -1;
}
else
{
Player.moveVector += 1;
}
}
Player.position += Player.moveVector;
}
Player.prototype.draw = function()
{
this.sprite.draw(context, this.position.x, this.position.y);
}
Vector2
var Vector2 = function()
{
this.x = 0;
this.y = 0;
};
Vector2.prototype.set = function(x,y)
{
this.x = x;
this.y = y;
};
Vector2.prototype.add = function(a_x,a_y)
{
return (this.x + a_x),(this.y + a_y);
}
Vector2.prototype.subtract = function(a_x,a_y)
{
return (this.x - a_x),(this.y - a_y);
}
Vector2.prototype.MultiplyScalar = function(input)
{
return (this.x * input),(this.y * input);
}
Vector2.prototype.Magnitude = function ()
{
return Math.sqrt((x*x) + (y*y)) //Gives magnitude of current vector2
}
Vector2.prototype.Normalize = function ()
{
var rect = new Vector2();
rect.x = this.x / this.Magnitude();
rect.y = this.y / this.Magnitude();
return ret;
}

Probably this error is because you are trying to access moveVector function wrong.
Player.moveVector.x += 1;
Here you are accessing moveVector on the Player function that is undefined. Probably what you wanted was something like this:
this.moveVector.x += 1;
Same for the other in your Player.prototype.update:
Player.prototype.update = function(deltaTime)
{
this.sprite.update(deltaTime);
if((keyboard.isKeyDown(keyboard.KEY_LEFT)) != (keyboard.isKeyDown(keyboard.KEY_RIGHT)))
{
if(keyboard.isKeyDown(keyboard.KEY_RIGHT))
{
this.moveVector.x += 1;
}
else
{
this.moveVector.x += -1;
}
}
if((keyboard.isKeyDown(keyboard.KEY_UP)) != (keyboard.isKeyDown(keyboard.KEY_UP)))
{
if(keyboard.isKeyDown(keyboard.KEY_DOWN))
{
this.moveVector += -1;
}
else
{
this.moveVector += 1;
}
}
this.position += this.moveVector;
}

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