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javascripthtml2d-games

how to add a play again feature to javascript game


I am having a hard time adding a play again function for my code and I do not know what I am doing wrong. Any help???? It seems like I do not update my gameArea after the player is dead in the game.

Also, my score does not show anymore after I used an image instead of text in the display. How can I add score while displaying images in my code

<!DOCTYPE html>
<html>
<head>


<style>
canvas {
    border:1px solid #d3d3d3;
    background-image: url("https://i.sstatic.net/WHu9Z.png");
}
</style>
</head>
<body>
<script>

var myGamePiece;
var myObstacles = [];
var myScore;

function startGame() {
    myGamePiece = new component(40, 40, "http://orig15.deviantart.net/a436/f/2012/101/1/c/mario_sprite_by_flamingdragon5000-d4vt57a.png", 10, 120, "image");
    myGamePiece.gravity = 0.05;
    myScore = new component("30px", "Consolas", "black", 280, 40, "text");
    myGameArea.start();
}

var myGameArea = {
    canvas : document.createElement("canvas"),
    start : function() {
        this.canvas.width = 480;
        this.canvas.height = 350;
        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);
    }
}

function component(width, height, color, x, y, type) {
    this.type = type;
    if (type == "image") {
        this.image = new Image();
        this.image.src = color;
    }
    this.score = 0;
    this.width = width;
    this.height = height;
    this.speedX = 0;
    this.speedY = 0;
    this.x = x;
    this.y = y;
    this.gravity = 0;
    this.gravitySpeed = 0;
    this.update = function() {
        ctx = myGameArea.context;
        if (this.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.gravitySpeed += this.gravity;
        this.x += this.speedX;
        this.y += this.speedY + this.gravitySpeed;
        this.hitBottom();
    }
    this.hitBottom = function() {
        var rockbottom = myGameArea.canvas.height - this.height -23;
        if (this.y > rockbottom) {
            this.y = rockbottom;
            this.gravitySpeed = 0;
        }
    }
    this.crashWith = function(otherobj) {
        var myleft = this.x;
        var myright = this.x + (this.width);
        var mytop = this.y;
        var mybottom = this.y + (this.height);
        var otherleft = otherobj.x;
        var otherright = otherobj.x + (otherobj.width);
        var othertop = otherobj.y;
        var otherbottom = otherobj.y + (otherobj.height);
        var crash = true;
        if ((mybottom < othertop) || (mytop > otherbottom) || (myright < otherleft) || (myleft > otherright)) {
            crash = false;
        }
        return crash;
    }
}

function updateGameArea() {
    var x, height, gap, minHeight, maxHeight, minGap, maxGap;
    for (i = 0; i < myObstacles.length; i += 1) {
        if (myGamePiece.crashWith(myObstacles[i])) {
            return;
        }
    }
    myGameArea.clear();
    myGameArea.frameNo += 1;
    if (myGameArea.frameNo == 1 || everyinterval(150)) {
        x = myGameArea.canvas.width;
        minHeight = 20;
        maxHeight = 200;
        height = Math.floor(Math.random()*(maxHeight-minHeight+1)+minHeight);
        minGap = 90;
        maxGap = 200;
        gap = Math.floor(Math.random()*(maxGap-minGap+1)+minGap);
        myObstacles.push(new component(50, height, "green", x, 0));
        myObstacles.push(new component(50, x - height - gap, "green", x, height + gap));
    }
    for (i = 0; i < myObstacles.length; i += 1) {
        myObstacles[i].x += -1;
        myObstacles[i].update();
    }
    myScore.text="SCORE: " + myGameArea.frameNo;
    myScore.update();
    myGamePiece.newPos();
    myGamePiece.update();
}

function everyinterval(n) {
    if ((myGameArea.frameNo / n) % 1 == 0) {return true;}
    return false;
}

function accelerate(n) {
    myGamePiece.gravity = n;
}

function clickPlayagain() {
     myGameArea.stop(); 

    // myGameArea2.stop();  
    startGame();


}
startGame();
</script>
<br>
<button onmousedown="accelerate(-0.15)" onmouseup="accelerate(0.08)">ACCELERATE</button>
<button id="playagain" onclick="clickPlayagain()">Play again</button>

<p>Use the ACCELERATE button to stay in the air</p>
</body>
</html>

Solution

  • Hope it helps:

    <!DOCTYPE html>
    <html>
    <head>
    
    
    <style>
    canvas {
        border:1px solid #d3d3d3;
        background-image: url("https://i.sstatic.net/WHu9Z.png");
    }
    </style>
    </head>
    <body>
    <script>
    
    var myGamePiece;
    var myObstacles = [];
    var myScore;
    var myGameArea;
    
    function startGame() {
        myGamePiece = new component(40, 40, "http://orig15.deviantart.net/a436/f/2012/101/1/c/mario_sprite_by_flamingdragon5000-d4vt57a.png", 10, 120, "image");
        myGamePiece.gravity = 0.05;
        myScore = new component("30px", "Consolas", "black", 280, 40, "text");
        if(myGameArea){
            document.removeChild(myGameArea.canvas);
        }
        myGameArea = {
            canvas : document.createElement("canvas"),
            start : function() {
                this.canvas.width = 480;
                this.canvas.height = 350;
                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);
            }
        }
        myGameArea.start();
    }
    
    function reset(){
        myGamePiece = undefined;
        myObstacles = [];
        myScore = "";
    }
    
    function component(width, height, color, x, y, type) {
        this.type = type;
        if (type == "image") {
            this.image = new Image();
            this.image.src = color;
        }
        this.score = 0;
        this.width = width;
        this.height = height;
        this.speedX = 0;
        this.speedY = 0;
        this.x = x;
        this.y = y;
        this.gravity = 0;
        this.gravitySpeed = 0;
        this.update = function() {
            ctx = myGameArea.context;
            if (this.type == "image") {
                ctx.drawImage(this.image,
                    this.x,
                    this.y,
                    this.width, this.height);
            }
            if (this.type == "text") {
                ctx.font = this.width + " " + this.height;
                ctx.fillStyle = color;
                ctx.fillText(this.text, this.x, this.y);
            }
            ctx.fillStyle = color;
            ctx.fillRect(this.x, this.y, this.width, this.height);
        }
        this.newPos = function() {
            this.gravitySpeed += this.gravity;
            this.x += this.speedX;
            this.y += this.speedY + this.gravitySpeed;
            this.hitBottom();
        }
        this.hitBottom = function() {
            var rockbottom = myGameArea.canvas.height - this.height -23;
            if (this.y > rockbottom) {
                this.y = rockbottom;
                this.gravitySpeed = 0;
            }
        }
        this.crashWith = function(otherobj) {
            var myleft = this.x;
            var myright = this.x + (this.width);
            var mytop = this.y;
            var mybottom = this.y + (this.height);
            var otherleft = otherobj.x;
            var otherright = otherobj.x + (otherobj.width);
            var othertop = otherobj.y;
            var otherbottom = otherobj.y + (otherobj.height);
            var crash = true;
            if ((mybottom < othertop) || (mytop > otherbottom) || (myright < otherleft) || (myleft > otherright)) {
                crash = false;
            }
            return crash;
        }
    }
    
    function updateGameArea() {
        var x, height, gap, minHeight, maxHeight, minGap, maxGap;
        for (i = 0; i < myObstacles.length; i += 1) {
            if (myGamePiece.crashWith(myObstacles[i])) {
                return;
            }
        }
        myGameArea.clear();
        myGameArea.frameNo += 1;
        if (myGameArea.frameNo == 1 || everyinterval(150)) {
            x = myGameArea.canvas.width;
            minHeight = 20;
            maxHeight = 200;
            height = Math.floor(Math.random()*(maxHeight-minHeight+1)+minHeight);
            minGap = 90;
            maxGap = 200;
            gap = Math.floor(Math.random()*(maxGap-minGap+1)+minGap);
            myObstacles.push(new component(50, height, "green", x, 0));
            myObstacles.push(new component(50, x - height - gap, "green", x, height + gap));
        }
        for (i = 0; i < myObstacles.length; i += 1) {
            myObstacles[i].x += -1;
            myObstacles[i].update();
        }
        myScore.text="SCORE: " + myGameArea.frameNo;
        myScore.update();
        myGamePiece.newPos();
        myGamePiece.update();
    }
    
    function everyinterval(n) {
        if ((myGameArea.frameNo / n) % 1 == 0) {return true;}
        return false;
    }
    
    function accelerate(n) {
        myGamePiece.gravity = n;
    }
    
    function clickPlayagain() {
         reset();
         startGame();
    
    }
    startGame();
    </script>
    <br>
    <button onmousedown="accelerate(-0.15)" onmouseup="accelerate(0.08)">ACCELERATE</button>
    <button id="playagain" onclick="clickPlayagain()">Play again</button>
    
    <p>Use the ACCELERATE button to stay in the air</p>
    </body>
    </html>