So we pretty much have this program working fine, we just need a little help, or a good pointer in the right direction on how we would start and stop the animation. I have tried several methods and none seem to have worked. I have spent a good amount of time online attempting to find help for the solution. I have come to believe that the problem lies somewhere in the lines that tell the shape to move. Thank you for any help in advance.
JS:
var myGamePiece;
function startGame() {
myGamePiece = new component(30, 30, "red", 10, 120);
myGameArea.start();
}
var myGameArea = {
canvas : document.createElement("canvas"),
start : function() {
this.canvas.width = 480;
this.canvas.height = 270;
this.context = this.canvas.getContext("2d");
document.body.insertBefore(this.canvas, document.body.childNodes[0]);
this.interval = setInterval(updateGameArea, 20);
},
clear : function() {
this.context.clearRect(0, 0, this.canvas.width, this.canvas.height);
}
}
function component(width, height, color, x, y) {
this.width = width;
this.height = height;
this.speedX = 0;
this.speedY = 0;
this.x = x;
this.y = y;
this.update = function() {
ctx = myGameArea.context;
ctx.fillStyle = color;
ctx.fillRect(this.x, this.y, this.width, this.height);
}
this.newPos = function() {
this.x += this.speedX;
this.y += this.speedY;
}
}
function updateGameArea() {
myGameArea.clear();
myGamePiece.newPos();
myGamePiece.update();
}
function moveup() {
myGamePiece.speedY -= 1;
}
function movedown() {
myGamePiece.speedY += 1;
}
function moveleft() {
myGamePiece.speedX -= 1;
}
function moveright() {
myGamePiece.speedX += 1;
}
HTML:
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0"/>
<script type="text/javascript" src="HallettBrocatoLab2.js"></script>
<style>
canvas {
border:1px solid #d3d3d3;
background-color: #f1f1f1;
}
</style>
</head>
<body onload="startGame()">
<div style="text-align:center;width:480px;">
<button onclick="moveup()">UP</button><br><br>
<button onclick="moveleft()">LEFT</button>
<button onclick="moveright()">RIGHT</button><br><br>
<button onclick="movedown()">DOWN</button><br><br>
<button onclick="start()">Start</button>
<button onclick="stop()">Stop</button>
</div>
<p>If you click a button the red square will start moving. Click the same button many times, and it will move faster and faster.</p>
</body>
</html>
The clearInterval() method clears a timer set with the setInterval() method.
The ID value returned by setInterval() is used as the parameter for the clearInterval() method.
add a function end pauseGame()
function pauseGame(){
clearInterval(this.interval);
}
change the definition of updateGameArea function
function updateGameArea() {
if(condition_to_stop){
myGameArea.pauseGame();
}
myGameArea.clear();
myGamePiece.newPos();
myGamePiece.update();
}
Related
I want to make the canvases PNG file, when exported, to be not squished ( Original size: Width: 480 pixels, height: 360 pixels. ) and plus, have the blue background color ( Color: #85c9ff ) . Source:
HTML:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width">
<title>Flippy in JavaScript! - Replit</title>
<link href="style.css" rel="stylesheet" type="text/css" />
</head>
<body onload="startGame()">
<canvas id="flippyGoesHere"></canvas>
<center>
<button onmousedown="moveup()" onmouseup="clearmove()" ontouchstart="moveup()">UP</button><br><br>
<div>
<button onmousedown="moveleft()" onmouseup="clearmove()" ontouchstart="moveleft()">LEFT</button>
<button onmousedown="moveright()" onmouseup="clearmove()" ontouchstart="moveright()">RIGHT</button>
<br>
<br>
</div>
<button onmousedown="movedown()" onmouseup="clearmove()" ontouchstart="movedown()">DOWN</button>
<br>
<br>
<button onclick="exportAsPng()">EXPORT AS IMAGE</button>
<br>
<br>
</center>
<script src="script.js"></script>
</body>
</html>
JS:
var myGamePiece;
var imgLink = document.getElementById("imgLink")
function startGame() {
myGamePiece = new component(20, 10, "/flippy.svg", 140, 70, "image");
myGameArea.start();
myGameArea.context.fillStyle = "#85c9ff"
myGameArea.context.fillRect(0, 0, myGameArea.canvas.width, myGameArea.canvas.height)
}
var myGameArea = {
canvas: document.getElementById("flippyGoesHere"),
start: function () {
this.context = this.canvas.getContext("2d");
document.body.insertBefore(this.canvas, document.body.childNodes[0]);
this.frameNo = 0;
this.interval = setInterval(updateGameArea, 20);
},
clear: function () {
this.context.clearRect(0, 0, this.canvas.width, this.canvas.height);
},
stop: function () {
clearInterval(this.interval);
}
}
function component(width, height, color, x, y, type) {
this.type = type;
if (type == "image") {
this.image = new Image();
this.image.src = color;
}
this.width = width;
this.height = height;
this.speedX = 0;
this.speedY = 0;
this.x = x;
this.y = y;
this.update = function () {
ctx = myGameArea.context;
if (type == "image") {
ctx.drawImage(this.image,
this.x,
this.y,
this.width, this.height);
} else {
ctx.fillStyle = color;
ctx.fillRect(this.x, this.y, this.width, this.height);
}
}
this.newPos = function () {
this.x += this.speedX;
this.y += this.speedY;
}
}
function updateGameArea() {
myGameArea.clear();
myGamePiece.newPos();
myGamePiece.update();
}
function moveup() {
myGamePiece.speedY = -1;
}
function movedown() {
myGamePiece.speedY = 1;
}
function moveleft() {
myGamePiece.speedX = -1;
}
function moveright() {
myGamePiece.speedX = 1;
}
function clearmove() {
myGamePiece.speedX = 0;
myGamePiece.speedY = 0;
}
function exportAsPng() {
imgLink.setAttribute("href", myGameArea.canvas.toDataURL())
imgLink.click()
}
And CSS, I don't know why:
body {
margin: 0;
}
a#imgLink {
display: none;
}
a#imgLink::before {
content: attr(href);
}
canvas#flippyGoesHere {
width: 480px;
height: 360px;
background-color: #85c9ff;
}
button { /* For all buttons! */
cursor: pointer;
}
Demo is here!
Here's the resulted image, when the turtle is not moving:
Building on KeroppiMomo's answer ...
Use the myGameArea.clear() method to colour the background too
var myGameArea = {
...
clear: function () {
myGameArea.context.fillStyle = "#85c9ff"
myGameArea.context.fillRect(0, 0, myGameArea.canvas.width,
myGameArea.canvas.height)
},
Get rid of all of the css for canvas#flippyGoesHere, that is just confusing things as it's affecting the display of the canvas.
You can set the canvas size in the html like KeroppiMomo suggested, or you can set it in the javascript (perhaps in your startGame() function):
myGameArea.canvas.height = 500
myGameArea.canvas.width = 500
You can see that the width and height of the canvas is not what you specified in CSS: myGameArea.canvas.width is 300 and myGameArea.canvas.height is 150. The problem is that the actual size of the canvas is different from its display size.
Setting the canvas size in HTML reveals that the exported image is the same as the canvas.
<canvas id="flippyGoesHere" width="480" height="360"></canvas>
The issue with the background color also lies in the CSS. Specifying the background color in CSS only displays that color, not rendering it in the canvas.
Filling the canvas with the background color (and for good practice, removing the background-color in CSS) should solve the problem.
this.update = function () {
ctx = myGameArea.context;
ctx.fillStyle = "#85c9ff";
ctx.fillRect(0, 0, width, height);
// ...
}
So i'm new to this and have probably coded it wrong to start off with. I'm thinking after doing research that i should have stored my other game pieces in an array or as seperate variables. Please correct me if im wrong.
Here is my code
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0"/>
<style>
canvas {
border:5px solid #d3d3d3;
background-color: green;
}
</style>
</head>
<body onload="startGame()">
<script>
var myGamePiece;
var myObstacle
function startGame() {
myGamePiece = new component(30, 30, "black", 350, 445);
blueGamePiece = new component(20, 20, "blue", 20, 20);
whiteGamePiece = new component(5, 40, "white",400, 20);
brownGamePiece = new component(25, 25, "brown", 650, 20);
myGameArea.start();
}
var myGameArea = {
canvas : document.createElement("canvas"),
start : function() {
this.canvas.width = 700;
this.canvas.height = 480;
this.context = this.canvas.getContext("2d");
document.body.insertBefore(this.canvas, document.body.childNodes[0]);
this.interval = setInterval(updateGameArea, 20);
window.addEventListener('keydown', function (e) {
myGameArea.key = e.keyCode;
})
window.addEventListener('keyup', function (e) {
myGameArea.key = false;
})
},
clear : function() {
this.context.clearRect(0, 0, this.canvas.width, this.canvas.height);
},
stop : function() {
clearInterval(this.interval);
}
}
function component(width, height, color, x, y) {
this.width = width;
this.height = height;
this.speedX = 0;
this.speedY = 0;
this.x = x;
this.y = y;
this.update = function(){
ctx = myGameArea.context;
ctx.fillStyle = color;
ctx.fillRect(this.x, this.y, this.width, this.height);
}
this.newPos = function() {
this.x += this.speedX;
this.y += this.speedY;
}
}
function updateGameArea() {
myGameArea.clear();
myGamePiece.speedX = 0;
myGamePiece.speedY = 0;
if (myGameArea.key && myGameArea.key == 37) {myGamePiece.speedX = -5; }
if (myGameArea.key && myGameArea.key == 39) {myGamePiece.speedX = 5;}
myGamePiece.newPos();
myGamePiece.update();
myGamePiece.update();
blueGamePiece.y += 1;
blueGamePiece.update();
whiteGamePiece.y +=3;
whiteGamePiece.update();
brownGamePiece.y +=2;
brownGamePiece.update();
}
</script>
</body>
</html>
I simply want to stop myGamePiece leaving the canvass not bounce it back.
Any other advice would be more than welcome.
Thankyou very much in advance.
Solution: Replace "this.update" function with this code.
this.update = function(){
if(this.x < 0){this.x = 0}
if(this.y < 0){this.y = 0}
if(this.x + this.width > myGameArea.canvas.width){this.x = myGameArea.canvas.width - this.width}
if(this.y + this.height > myGameArea.canvas.height){this.y = myGameArea.canvas.height - this.height}
ctx = myGameArea.context;
ctx.fillStyle = color;
ctx.fillRect(this.x, this.y, this.width, this.height);
}
I am developing a game using JavaScript and I want to have the scenes of a classic 1990's game where the text appears in split-second intervals then disappears once the user clicks next. Is there a way to do this just using JavaScript?
I'm using PhpStorm for the moment. I have yet to start as I'm designing the blueprints with my friend. I am also a bit confused about where to start because I have searched for methods but no luck.
Since You Are Making A Game You Will Be Having A Canvas Too
So Use This Code If have Any Questions Ask Me
HTML
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0"/>
<style>
canvas {
border:1px solid #d3d3d3;
background-color: #f1f1f1;
}
</style>
</head>
<body onload="startGame()">
</body>
</html>
Javascript
<script>
var myGamePiece;
var myTitle;
//Function To Start the Game
function startGame() {
myTitle = new component("20px", "Consolas", "black", 150, 135, "text");
myGameArea.start();
}
// myGameArea Is The Canvas in Which The Whole Drawing Process Will be Drawn & The Title Is Drawn In This Too
var myGameArea = {
canvas : document.createElement("canvas"),
start : function() {
this.canvas.width = 480;
this.canvas.height = 270;
this.context = this.canvas.getContext("2d");
document.body.insertBefore(this.canvas, document.body.childNodes[0]);
this.frameNo = 0;
// setInterval Function Draws the Canvas 50 times in a Second You Can Change The Value Of 50 IF You Want
this.interval = setInterval(updateGameArea, 50);
},
clear : function() {
this.context.clearRect(0, 0, this.canvas.width, this.canvas.height);
},
}
// Component Function Makes a New Component Like We Have A Title By Component Function
function component(width, height, color, x, y, type) {
this.type = type;
this.width = width;
this.height = height;
this.x = x;
this.y = y;
this.update = function() {
ctx = myGameArea.context;
// This Checks if Component Type is Text And Every Frame is Divided By 70 Then Nothing Will Happen Else Your Title Will Appear You Glitch is Because Of This Function You Can The Value As You Want
if (this.type == "text" && everyinterval(70) ) {
} else {
ctx.font = this.width + " " + this.height;
ctx.fillStyle = color;
ctx.fillText(this.text, this.x, this.y);
}
}
}
// This Function Updates GameArea (The Canvas) I Added The Frame No So You Can See The Glitch At Every Frame Number
function updateGameArea() {
myGameArea.frameNo += 1;
myGameArea.clear();
myTitle.text = "Title Glitching at " + myGameArea.frameNo;
myTitle.update();
}
// The Function To Make The Glitch Which Divide's The FrameNo By "n" Number
function everyinterval(n) {
if ((myGameArea.frameNo / n) % 1 == 0) {return true;}
return false;
}
</script>
Hope This Helps!
I'm making a simple Javascript game for a school project. I'm trying to replace the red square with an image(in the following link).
enter link description here
How can i achieve this?
Great question! Use a snippet to post your code. This link should provide a complete answer add image
var myGamePiece;
function startGame() {
myGamePiece = new component(30, 30, "red", 10, 120);
myGameArea.start();
}
var myGameArea = {
canvas : document.createElement("canvas"),
start : function() {
this.canvas.width = 480;
this.canvas.height = 270;
this.context = this.canvas.getContext("2d");
document.body.insertBefore(this.canvas, document.body.childNodes[0]);
this.interval = setInterval(updateGameArea, 20);
},
clear : function() {
this.context.clearRect(0, 0, this.canvas.width, this.canvas.height);
}
}
function component(width, height, color, x, y) {
this.width = width;
this.height = height;
this.speedX = 0;
this.speedY = 0;
this.x = x;
this.y = y;
this.update = function() {
ctx = myGameArea.context;
ctx.fillStyle = color;
ctx.fillRect(this.x, this.y, this.width, this.height);
}
this.newPos = function() {
this.x += this.speedX;
this.y += this.speedY;
}
}
function updateGameArea() {
myGameArea.clear();
myGamePiece.newPos();
myGamePiece.update();
}
function moveup() {
myGamePiece.speedY -= 1;
}
function movedown() {
myGamePiece.speedY += 1;
}
function moveleft() {
myGamePiece.speedX -= 1;
}
function moveright() {
myGamePiece.speedX += 1;
}
canvas {
border:1px solid #d3d3d3;
background-color: #f1f1f1;
}
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0"/>
</head>
<body onload="startGame()">
<div style="text-align:center;width:480px;">
<button onclick="moveup()">UP</button><br><br>
<button onclick="moveleft()">LEFT</button>
<button onclick="moveright()">RIGHT</button><br><br>
<button onclick="movedown()">DOWN</button>
</div>
<p>If you click a button the red square will start moving. Click the same button many times, and it will move faster and faster.</p>
</body>
</html>
I am trying to develop a game and i am starting to dip my toes into the HTML <canvas> tag and using it with javascript. My program here is my work in progress clone of PONG. I have managed to add the two paddles with no error but as i have added the Ball function it simply refuses to draw anything on the screen and thus i am given a page covered in black.
Could it be because i am using classes?
Here is the code:
// ctx.fillStyle = 'rgba(red, green, blue, alpha)';
// ctx.fillRect(x, y, width, height);
var canvas;
var ctx;
var dx = 5;
var dy = 5;
//Class Definitions
function Game(width, height, colour) {
this.width = width;
this.height = height;
this.colour = colour;
}
function Player(width, height, colour, x, y, up, down) {
this.width = width;
this.height = height;
this.colour = colour;
this.x = x;
this.y = y;
this.up = up;
this.down = down;
this.move = function(ny) {
this.y = this.y + ny;
ctx.fillStyle = this.colour;
ctx.fillRect(this.x, this.y, this.width, this.height);
};
}
function Ball(width, height, colour, x , y, isTouched, isInGoal) {
this.width = width;
this.height = height;
this.colour = colour;
this.x = x;
this.y = y;
this.isTouched = isTouched;
this.isInGoal = isInGoal;
this.move = function() {
clear();
this.x = this.x + 1;
ctx.fillStyle = this.colour;
ctx.fillRect(this.x, this.y, this.width, this.height);
};
}
//Creating new Classes
var gameStage = new Game((window.innerWidth), (window.innerHeight), 'rgb(0,0,0)');
var paddleOne = new Player(10, 150, 'rgb(255,255,255)', (gameStage.width/10), (gameStage.height/2), 38, 40);
var paddleTwo = new Player(10, 150, 'rgb(255,255,255)', (gameStage.width/1.1), (gameStage.height/2), 87, 83);
var ball = new Ball(20, 20, 'rgb(255,255,255)', (gameStage.width/2), (gameStage.height/2), 0, 0);
//Initialisation
function init(){
canvas = document.getElementById('game');
canvas.setAttribute('width', gameStage.width);
canvas.setAttribute('height', gameStage.height);
canvas.setAttribute('tabindex', 0);
if (game.getContext){
ctx = canvas.getContext('2d');
return setInterval(ball.move, 10);
return setInterval(draw, 10);
}
}
//Canvas Functions
function clear(){
ctx.clearRect(0, 0, gameStage.width, gameStage.height);
}
function draw() {
clear();
ctx.fillStyle = gameStage.colour;
ctx.fillRect(0, 0, gameStage.width, gameStage.height);
ctx.fillStyle = paddleOne.colour;
ctx.fillRect(paddleOne.x, paddleOne.y, paddleOne.width, paddleOne.height);
ctx.fillStyle = paddleTwo.colour;
ctx.fillRect(paddleTwo.x, paddleTwo.y, paddleTwo.width, paddleTwo.height);
console.log("PlayerOne Y Coordinate: " + paddleOne.y + "\n");
console.log("PlayerTwo Y Coordinate: " + paddleTwo.y + "\n");
}
//Player Control
function doKeyDown(e) {
if (e.keyCode == paddleOne.up){
paddleOne.move(-5);
} else if (e.keyCode == paddleOne.down) {
paddleOne.move(5);
} else if (e.keyCode == paddleTwo.up) {
paddleTwo.move(-5);
} else if (e.keyCode == paddleTwo.down) {
paddleTwo.move(5);
}
}
//For HTML
function beginStuff(){
init();
window.addEventListener('keydown', doKeyDown, true);
}
* { margin: 0; padding: 0;}
body, html {height: 100%;}
#game {
position: absolute;
width:100%;
height:100%;
background-color: #000000;
}
<!DOCTYPE HTML>
<htmL>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>A game</title>
<script type="text/javascript" src="game.js"></script>
<link rel="stylesheet" type="text/css" href="style.css">
</head>
<body onload="beginStuff();" >
<canvas id="game">
Please upgrade your browser to support HTML5. <br/>
</canvas>
</body>
</htmL>
This looks wrong to me:
return setInterval(ball.move, 10);
return setInterval(draw, 10);
Firstly, you've got 2 returns. Secondly, you've lost the binding on the move method:
return setInterval(ball.move.bind(ball), 10);
If that doesn't fix it I suggest stepping through in a debugger, line-by-line, making sure that everything is doing exactly what you expect it to.
With help from #skirtle, i moved the ball.move(); to the draw() function and removed the clear() call from the ball.move() function.