I am making a game with html and javascript. Just for clarification, this is not a duplicate or anything. Nothing has the answer I need. Also before I explain, I want to say I have no trouble with the key listener, my game knows when a key is pressed and when it is released. Okay, I have 5 frames of a character walking. I have a while loop that basically says while the key D is pressed or Right arrow is pressed, then increment the frames to make it look like the character is walking. Then it has a setTimeout function that pauses for 1/10 of a second. This should make it look like the character is walking. I know it has something to do with the setTimeout() function. Here is the while loop:
while (keys[68] || keys[39]) {
charFrame++;
setTimeout(function() {
}, 100);
}
Then here is my code:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Sparring Spartans</title>
<style type="text/css">
</style>
</head>
<body>
<canvas id="canvas" width="1000" height="600"></canvas>
<script type="text/javascript">
var canvas = document.getElementById("canvas");
var context = canvas.getContext("2d");
var width = canvas.width;
var height = canvas.height;
var groundX = 0, groundY = 400;
var playerx = width/2, playery = groundY-120;
var charFrame = 1;
var speed = 4;
var keys = [];
window.addEventListener("keydown", function(e) {
keys[e.keyCode] = true;
}, false);
window.addEventListener("keyup", function(e) {
delete keys[e.keyCode];
}, false);
var spartan1 = new Image();
spartan1.src = "spartan1.png";
var spartan2 = new Image();
spartan2.src = "spartan2.png";
var spartan3 = new Image();
spartan3.src = "spartan3.png";
var spartan4 = new Image();
spartan4.src = "spartan4.png";
var spartan5 = new Image();
spartan5.src = "spartan5.png";
var stone = new Image();
stone.src = "stone.png";
function game() {
update();
render();
}
function player() {
if (charFrame === 1) {
context.drawImage(spartan1, playerx, playery);
} else if (charFrame === 2) {
context.drawImage(spartan2, playerx, playery);
} else if (charFrame === 3) {
context.drawImage(spartan3, playerx, playery);
} else if (charFrame === 4) {
context.drawImage(spartan4, playerx, playery);
} else if (charFrame === 5) {
context.drawImage(spartan5, playerx, playery);
}
}
function ground() {
for (var i = 0; i <= 1000; i += 55) {
context.drawImage(stone, i, groundY);
}
for (var i = 0; i <= 1000; i += 55) {
context.drawImage(stone, i, groundY+55);
}
for (var i = 0; i <= 1000; i += 55) {
context.drawImage(stone, i, groundY+110);
}
for (var i = 0; i <= 1000; i += 55) {
context.drawImage(stone, i, groundY+165);
}
}
function manager() {
ground();
while (keys[68] || keys[39]) {
charFrame++;
setTimeout(function() {
}, 100);
}
player();
}
function update() {
manager();
player();
}
function render() {
context.fillStyle = "#AFE4FF";
context.fillRect(0, 0, width, height);
manager();
}
setInterval(function() {
game();
}, 1000/30);
</script>
</body>
</html>
What am I doing wrong? I know it HAS to be the setTimeout, but I have tried to fix this problem many times. The images don't even change.
Because your manager function gets called 30 times per second, you should check your keypress once per frame using an if statement instead of a loop:
function manager() {
ground();
if (keys[68] || keys[39]) {
charFrame++;
}
}
In addition, your manager function is getting called twice per frame, once in the update function and once in the render function. Also, your player function is called both in update and in manager, again twice per frame. Your code will need some refactoring in order to work properly, to make sure nothing gets called twice per frame.
Related
I'm trying to change image position using JavaScript using my code but for some reason it doesn't work. Can someone explain the reason.
var walk, isWaveSpawned = true;
var walkers = [];
function start()
{
walk = document.getElementById("walk");
draw(); //Animation function
}
function draw()
{
if(isWaveSpawned) //Generate a wave of 5 "walkers"
{
isWaveSpawned = false;
for(var i = 0; i < 5; i++
walkers.push(new createWalker());
}
for(var o = 0; o < walkers.length; o++) //Add 1px to x position after each frame
{
walkers[o].x += walkers[o].speed;
walkers[o].image.style.left = walkers[o].x;
walkers[o].image.style.top = walkers[o].y;
}
requestAnimationFrame(draw);
}
function createWalker()
{
this.x = 0;
this.y = 100;
this.speed = 1;
this.image = walk.cloneNode(false); //Possible cause of issue
}
<!DOCTYPE html>
<html>
<body onload="start()">
<img id="walk" src="https://i.imgur.com/ArYIIjU.gif">
</body>
</html>
My GIF image is visible in top left corner but doesn't move.
P.S. Added a HTML/JS snippet but it outputs some errors while in my end these errors are not seen.
First let's modify the way you're cloning the gif - get rid of this line:
this.image = walk.cloneNode(false);
and insert this:
this.image = document.createElement("img");
This will create a fresh empty HTML image element.
Now assign it's .src property the source of your gif:
this.image.src=document.getElementById("walk").src;
and set the CSS position property to absolute:
this.image.style="position:absolute;";
finally add this new image element to the body using:
document.body.appendChild(this.image);
If you hit run you will still not see any movement because there's still a little fix to do!
Find this line:
walkers[o].image.style.left = walkers[o].x;
and change it to this:
walkers[o].image.style.left = walkers[o].x + "px";
var walk, isWaveSpawned = true;
var walkers = [];
function start() {
walk = document.getElementById("walk");
draw(); //Animation function
}
function draw() {
if (isWaveSpawned) //Generate a wave of 5 "walkers"
{
isWaveSpawned = false;
for (var i = 0; i < 5; i++)
walkers.push(new createWalker());
}
for (var o = 0; o < walkers.length; o++) //Add 1px to x position after each frame
{
walkers[o].x += walkers[o].speed;
walkers[o].image.style.left = walkers[o].x + "px";
walkers[o].image.style.top = walkers[o].y + "px";
}
requestAnimationFrame(draw);
}
function createWalker() {
this.x = 0;
this.y = 100;
this.speed = 1;
this.image = document.createElement("img");
this.image.src = document.getElementById("walk").src;
this.image.style = "position:absolute;";
document.body.appendChild(this.image);
}
start();
<body>
<img id="walk" src="https://i.imgur.com/ArYIIjU.gif">
</body>
Im trying to make simple game in canvas. I made animation for hero using setTimeout() function. I check pressed keys with function moove(e):
Everything works pretty fine when i press leftarrow or rightarrow for the first time, but then hero doesnt moove. Any recomendations to the code is appreciated.
var cns = document.getElementById("can");
cns.height = 600;
cns.width = 300;
var ctx = cns.getContext("2d");
var hero = new Image();
hero.src = "images/hero.png";
hero.onload = function() {
ctx.drawImage(hero, 120, 570);
hero.xx = 120;
hero.yy = 570;
};
var intervalL, intervalR, intervalLL, intervalRR;
var keys = [];
function moove(e) {
keys[e.keyCode] = (e.type == "keydown");
if (keys[37]) {
clearTimeout(intervalR);
clearTimeout(intervalRR);
goLeft(hero);
} else {
clearTimeout(intervalL);
clearTimeout(intervalLL);
}
if (keys[39]) {
clearTimeout(intervalL);
clearTimeout(intervalLL);
goRight(hero);
} else {
clearTimeout(intervalR);
clearTimeout(intervalRR);
}
}
function goLeft(img) {
var x = img.xx,
y = img.yy;
function f() {
ctx.clearRect(img.xx, img.yy, img.width, img.height);
ctx.drawImage(img, x, y);
img.xx = x;
img.yy = y;
x -= 1.2;
if (x < -35) {
x = cns.width;
}
}
if (!intervalL) {
intervalL = setTimeout(function run() {
f();
intervalLL = setTimeout(run, 5);
}, 5);
}
}
Function goRight is similiar to goLeft.
Function moove is called in tag body onkeydown='moove(event)' onkeyup='moove(event)'.
You can check the project here: https://github.com/Fabulotus/Fabu/tree/master/Canvas%20game%20-%20dodge%20and%20jump
The reason it doesn't work the first time is because the first time through you are setting the position to its previous position (x = image.xx) then updating x after you draw. You should update the x value x -= 1.2 before calling drawImage
Here is a "working" version of your code:
var cns = document.getElementById("can");
cns.height = 170;
cns.width = 600;
var ctx = cns.getContext("2d");
var hero = new Image();
hero.src = "http://swagger-net-test.azurewebsites.net/api/Image";
hero.onload = function() {
ctx.drawImage(hero, cns.width-10, cns.height/2);
hero.xx = cns.width-10;
hero.yy = cns.height/2;
};
var intervalL, intervalR, intervalLL, intervalRR;
var keys = [];
function goLeft(img) {
function f() {
ctx.beginPath()
ctx.clearRect(0, 0, cns.width, cns.height);
ctx.drawImage(img, img.xx, img.yy);
img.xx--;
if (img.xx < -img.width) {
img.xx = cns.width;
}
}
if (!intervalL) {
intervalL = setTimeout(function run() {
f();
intervalLL = setTimeout(run, 5);
}, 5);
}
}
goLeft(hero)
<canvas id="can">
As you can see the function goLeft has been significantly simplified.
One recommendation: avoid the many setTimeout and clearTimeout instead use one setInterval to call a draw function that takes care of drawing everything on your game, all the other function should just update the position of your gameObjects.
I'm a bit new to JavaScript and have been playing around with Phaser lately. So I'm building an infinite side scroller and everything works fine except that my player won't collide with the walls. Both sprites have physics enabled and I have tried multiple solutions, none of which work. Can you please help me out?
function bloxo()
{
var game = new Phaser.Game(1200, 600, Phaser.CANVAS, 'gameStage', { preload: preload, create: create, update: update });
var prevHole = 3;
function preload() {
game.load.image('bloxoDown','../bloxo/assets/images/bloxoDown.png');
game.load.image('bloxoUp','../bloxo/assets/images/bloxoUp.png');
game.load.image('wall','../bloxo/assets/images/platform.png',400,200);
var space;
var esc;
var player;
var walls;
var score;
}
function create() {
//Canvas With a White Bacground and Physics is Created
game.stage.backgroundColor = "#ffffff";
game.physics.startSystem(Phaser.Physics.ARCADE);
//Sets the initial Score.
score = 0;
//Sets how fast the tiles move
tileSpeed = -300;
tileWidth = game.cache.getImage('wall').width;
tileHeight = game.cache.getImage('wall').height;;
//Keys for User Input are created
space = game.input.keyboard.addKey(Phaser.Keyboard.SPACEBAR);
esc = game.input.keyboard.addKey(Phaser.Keyboard.ESC);
//Adds Bloxo to the game as a sprite.
player = game.add.sprite(200,200,'bloxoDown');
player.scale.setTo(0.6, 0.6);
game.physics.enable(player, Phaser.Physics.ARCADE);
player.body.collideWorldBounds = true;
player.body.immovable = true;
//Walls Group is created
walls = game.add.physicsGroup();
walls.createMultiple(50, 'wall');
walls.enableBody = true;
game.physics.arcade.overlap(player, walls,null,this)
game.physics.arcade.collide(player,walls,gameOver);
// Stop the following keys from propagating up to the browser
game.input.keyboard.addKeyCapture([ Phaser.Keyboard.SPACEBAR, Phaser.Keyboard.ESC,]);
//Unpausing Function
window.onkeydown = function(event)
{
if (esc.onDown && (esc.timeDown > 2000))
{
if(game.paused)
{
game.paused = !game.paused;
pauseLbl.destroy();
}
}
}
//Add an initial platform
addWall();
//Add a platform every 3 seconds
var timerWorld = game.time.events.loop(500, addWall);
}
function update() {
if (space.isDown)
{
player.body.y -=5;
bloxoUp();
}
else
{
player.body.y +=5;
bloxoDown();
}
if(esc.isDown)
{
pauseGame();
}
}
function bloxoUp()
{
player.loadTexture('bloxoUp');
}
function bloxoDown()
{
player.loadTexture('bloxoDown');
}
function pauseGame()
{
game.paused = true;
pauseLbl = game.add.text(500, 300, 'Game Paused', { font: '30px Roboto', fill: '#aaaaaa' });
}
function addTile(x,y)
{
//Get a tile that is not currently on screen
var tile = walls.getFirstDead();
//Reset it to the specified coordinates
tile.reset(x,y);
tile.body.velocity.x = tileSpeed;
tile.body.immovable = true;
//When the tile leaves the screen, kill it
tile.checkWorldBounds = true;
tile.outOfBoundsKill = true;
}
function addWall()
{
//Speed up the game to make it harder
tileSpeed -= 1;
score += 1;
//Work out how many tiles we need to fit across the whole screen
var tilesNeeded = Math.ceil(game.world.height / tileHeight);
//Add a hole randomly somewhere
do
{
var hole = Math.floor(Math.random() * (tilesNeeded - 2)) + 1;
}while((hole > (prevHole + 2)) && (hole < (prevHole - 2)) );
prevHole = hole;
//Keep creating tiles next to each other until we have an entire row
//Don't add tiles where the random hole is
for (var i = 0; i < tilesNeeded; i++){
if (i != hole && (i != hole+1 && i != hole-1) && (i != hole+2 && i != hole-2)){
addTile(game.world.width, i * tileHeight);
}
}
}
function gameOver()
{
console.log("player hit");
player.kill();
game.state.start(game.state.current);
}
}
You have just to move collide call into your update method:
game.physics.arcade.collide(player, walls, gameOver);
Take a look to the runnable snippet below(I have resized the canvas for the preview, sorry) or Fiddle:
var game = new Phaser.Game(450, 150, Phaser.CANVAS, 'gameStage', {
preload: preload,
create: create,
update: update
});
var prevHole = 3;
function preload() {
game.load.image('bloxoDown', '../bloxo/assets/images/bloxoDown.png');
game.load.image('bloxoUp', '../bloxo/assets/images/bloxoUp.png');
game.load.image('wall', '../bloxo/assets/images/platform.png', 400, 100);
var space;
var esc;
var player;
var walls;
var score;
}
function create() {
//Canvas With a White Bacground and Physics is Created
game.stage.backgroundColor = "#ffffff";
game.physics.startSystem(Phaser.Physics.ARCADE);
//Sets the initial Score.
score = 0;
//Sets how fast the tiles move
tileSpeed = -300;
tileWidth = game.cache.getImage('wall').width;
tileHeight = game.cache.getImage('wall').height;;
//Keys for User Input are created
space = game.input.keyboard.addKey(Phaser.Keyboard.SPACEBAR);
esc = game.input.keyboard.addKey(Phaser.Keyboard.ESC);
//Adds Bloxo to the game as a sprite.
player = game.add.sprite(200, 200, 'bloxoDown');
player.scale.setTo(0.6, 0.6);
game.physics.enable(player, Phaser.Physics.ARCADE);
player.body.collideWorldBounds = true;
player.body.immovable = true;
//Walls Group is created
walls = game.add.physicsGroup();
walls.createMultiple(50, 'wall');
walls.enableBody = true;
game.physics.arcade.overlap(player, walls, null, this)
// remove your call to collide
// Stop the following keys from propagating up to the browser
game.input.keyboard.addKeyCapture([Phaser.Keyboard.SPACEBAR, Phaser.Keyboard.ESC, ]);
//Unpausing Function
window.onkeydown = function(event) {
if (esc.onDown && (esc.timeDown > 2000)) {
if (game.paused) {
game.paused = !game.paused;
pauseLbl.destroy();
}
}
}
//Add an initial platform
addWall();
//Add a platform every 3 seconds
var timerWorld = game.time.events.loop(500, addWall);
}
function update() {
if (space.isDown) {
player.body.y -= 5;
bloxoUp();
} else {
player.body.y += 5;
bloxoDown();
}
// move your collide call here
game.physics.arcade.collide(player, walls, gameOver);
if (esc.isDown) {
pauseGame();
}
}
function bloxoUp() {
player.loadTexture('bloxoUp');
}
function bloxoDown() {
player.loadTexture('bloxoDown');
}
function pauseGame() {
game.paused = true;
pauseLbl = game.add.text(500, 300, 'Game Paused', {
font: '30px Roboto',
fill: '#aaaaaa'
});
}
function addTile(x, y) {
//Get a tile that is not currently on screen
var tile = walls.getFirstDead();
//Reset it to the specified coordinates
if (tile) {
tile.reset(x, y);
tile.body.velocity.x = tileSpeed;
tile.body.immovable = true;
//When the tile leaves the screen, kill it
tile.checkWorldBounds = true;
tile.outOfBoundsKill = true;
}
}
function addWall() {
//Speed up the game to make it harder
tileSpeed -= 1;
score += 1;
//Work out how many tiles we need to fit across the whole screen
var tilesNeeded = Math.ceil(game.world.height / tileHeight);
var prevHole;
//Add a hole randomly somewhere
do {
var hole = Math.floor(Math.random() * (tilesNeeded - 2)) + 1;
} while ((hole > (prevHole + 2)) && (hole < (prevHole - 2)));
prevHole = hole;
//Keep creating tiles next to each other until we have an entire row
//Don't add tiles where the random hole is
for (var i = 0; i < tilesNeeded; i++) {
if (i != hole && (i != hole + 1 && i != hole - 1) && (i != hole + 2 && i != hole - 2)) {
addTile(game.world.width, i * tileHeight);
}
}
}
function gameOver() {
console.log("player hit");
player.kill();
game.state.start(game.state.current);
}
canvas{
border: 5px solid #333;
margin-left:25px;
margin-top:25px;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/phaser/2.6.2/phaser.min.js"></script>
I am trying to complete This tutorial on making a tic tac toe game using JavaScript and HTML5.
I've followed each step in the video multiple times. While my code seems to match the code in video I keep encountering an error: Uncaught Reference Error: draw is not defined. The error occurs in line 12.
I must be overlooking something. Can anyone point it out?
<!DOCTYPE html>
<html>
<head>
<title>Tic Tac Toe!</title>
<script type="text/javascript">
var c, canvas;
var turn = 1;
window.onload = function() {
canvas = document.getElementById("canvas");
c = canvas.getContext("2d");
draw();
}
var moves = [];
window.onclick = function(e) {
if(e.pageX < 500 && e.pageY < 500) {
var cX = Math.floor(e.pageX / (500 / 3));
var cY = Math.floor(e.pageY / (500 / 3));
var alreadyClicked = false;
for(i in moves) {
if(moves[i][0] == cX && moves[i][1] == cY) {
alreadyClicked = true;
}
}
if(alreadyClicked == false) {
moves[(moves.length)] = [cX, cY, turn];
turn = turn * -1;
draw();
}
}
var bg = new Image();
var x = new Image();
var o = new Image();
bg.src = "ttt_board.png";
x.src = "ttt_x.png";
o.src = "ttt_o.png";
function draw() {
c.clearRect(0, 0, 500, 500);
c.drawImage(bg, 0, 0);
for(i in moves) {
if(moves[i][2] == 1) {
c.drawImage(x, Math.floor(moves[i][0] * (500 / 3) + 10), Math.floor(moves[i][1](500 / 3) + 10))
} else {
c.drawImage(o, Math.floor(moves[i][0] * (500 / 3) + 10), Math.floor(moves[i][1] * (500 / 3) + 10));
}
}
}
};
</script>
</head>
<body>
<canvas id="canvas" width="500px" height="500px"></canvas>
</body>
</html>
The problem is that draw is defined in window.onclick, but you are trying to call it from window.onload. Are you sure you do not have a closing bracket missing before the definition of draw?
Try moving the draw() function out of the window.click function.
window.onclick = function(e) {
// ...
};
function draw() {
// ...
}
One of the major benefits of being strict with your indentation is that you can pick up these bugs very quickly.
window.click = function(e) {
// ...
function draw() {
// ...
}
};
Is the code you had.
As a result of draw being located inside of the window.onclick anonymous function, it is scoped there. Since window.onload does not share the scope of that anonymous function, you cannot access draw from window.onload. You should removed the draw function from your window.onclick event so that it may be called from other scopes.
function draw(){}
window.onload = function(){ /*code*/ };
window.onclick = function(){ /* code */ };
So I have these functions to fade a canvas in and out that aren't working the way I expect them to. Here's what I'm working with at the moment:
function fade_out ()
{
var canvas = document.getElementById("builder");
var context = canvas.getContext('2d');
console.log(context.globalAlpha);
context.globalAlpha -= 0.01;
if(context.globalAlpha > 0)
{
setTimeout(fade_out, 5);
}
}
function fade_in ()
{
var canvas = document.getElementById("builder");
var context = canvas.getContext('2d');
context.globalAlpha += 0.01;
if(context.globalAlpha < 1)
{
setTimeout(fade_in, 5);
}
}
My intent was to make it a half second fade. What I ended up with was it just blinking in and out in a flash. The console.log in the first function tells me it's not even close to working the way I expect it to. What went wrong here?
EDIT: There seems to be an endless loop going, and the context.globalAlpha is getting into 20 significant digits, even though I didn't use numbers like that.
function fade_in() {
setTimeout( function() {
var cn = document.getElementById("builder");
var ct = cn.getContext('2d').globalAlpha;
ct += 0.02;
if(ct >= 1) {
ct=1;
}
if (ct < 1) {
fade_in();
}
else {
return false;
}
}, 30);
}
function fade_out() {
setTimeout( function() {
var cn = document.getElementById("builder");
var ct = cn.getContext('2d').globalAlpha;
ct -= 0.02;
if(ct <= 0) {
ct=0;
}
if (ct > 0) {
fade_out();
}
else {
return false;
}
}, 30);
}