Question

我在网上看到了一个带有源代码的游戏，我想把红色方块改成Flappy bird的图像，因为游戏看起来就像它。你能帮我把红色方块改成图像吗？

HTML代码：

＆＃13;

<!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()">
<script>

var myGamePiece;
var myObstacles = [];
var myScore;

function startGame() {
    myGamePiece = new component(30, 30, "red", 10, 120);
    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 = 270;
        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;
    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 == "text") {
            ctx.font = this.width + " " + this.height;
            ctx.fillStyle = color;
            ctx.fillText(this.text, this.x, this.y);
        } 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;
        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 = 50;
        maxGap = 200;
        gap = Math.floor(Math.random()*(maxGap-minGap+1)+minGap);
        myObstacles.push(new component(10, height, "green", x, 0));
        myObstacles.push(new component(10, 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;
}
</script>
<br>
<button onmousedown="accelerate(-0.2)" onmouseup="accelerate(0.05)">ACCELERATE</button>
<p>Use the ACCELERATE button to stay in the air</p>
<p>How long can you stay alive?</p>
</body>
</html>

＆＃13;

您能提供更改控件和背景的代码吗？我想基于此自己制作游戏并了解更多信息。

Answer 1

（1）在HTML中定义图像并使用CSS隐藏它：

<img id="sourceImg" src="http://placebacon.net/40/40" style="display: none;">

（2）创建一个新的＆＃34;图像＆＃34;输入您的component功能：

if (this.type == "text") {
    ctx.font = this.width + " " + this.height;
    ctx.fillStyle = color;
    ctx.fillText(this.text, this.x, this.y);
} else if(this.type == "image") {
    var image = document.getElementById('sourceImg');
    ctx.drawImage(image, this.x, this.y)
} else {
    ctx.fillStyle = color;
    ctx.fillRect(this.x, this.y, this.width, this.height);
}

（3）在创建游戏时使用此新类型：

myGamePiece = new component(30, 30, null, 10, 120, "image");

（4）??

（5）利润！

＆＃13;

<!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()">
<img id="sourceImg" src="http://placebacon.net/40/40" style="display: none;">
<script>

var myGamePiece;
var myObstacles = [];
var myScore;

function startGame() {
    myGamePiece = new component(30, 30, null, 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 = 270;
        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;
    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 == "text") {
            ctx.font = this.width + " " + this.height;
            ctx.fillStyle = color;
            ctx.fillText(this.text, this.x, this.y);
        } else if(this.type == "image") {
            var image = document.getElementById('sourceImg');
            ctx.drawImage(image, this.x, this.y)
        } 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;
        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 = 50;
        maxGap = 200;
        gap = Math.floor(Math.random()*(maxGap-minGap+1)+minGap);
        myObstacles.push(new component(10, height, "green", x, 0));
        myObstacles.push(new component(10, 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;
}
</script>
<br>
<button onmousedown="accelerate(-0.2)" onmouseup="accelerate(0.05)">ACCELERATE</button>
<p>Use the ACCELERATE button to stay in the air</p>
<p>How long can you stay alive?</p>
</body>
</html>

＆＃13;

Answer 2

要修改后退颜色，请更改行

background-color：＃f1f1f1;

使用drawImage()

绘制图像

你可以在compponent函数上添加else if语句，taht创建正方形。

else if (this.type == "img") {
    var img=document.createElement('img');
    img.src=src;
    ctx.drawImage(img, this.x, this.y, this.width, this.height);
}

然后在控制你必须添加其他按钮并修改影响移动的方式，在newPos（）函数中就像这样：

this.newPos = function() {
    //this line increases gravity value
    this.gravitySpeed += this.gravity;
    //This line is movinh foward
    this.x += this.speedX;
    //This line makes the object falls
    this.y += this.speedY + this.gravitySpeed;

    this.hitBottom();
}

我已经在例子中将控件修改为向上和向下按钮。

＆＃13;

    <!DOCTYPE html>
    <html>
    <head>
    <meta name="viewport" content="width=device-width, initial-scale=1.0"/>
    <style>
    canvas {
        border:1px solid #d3d3d3;
        background-color: rgb(255,123,11);
    }
    </style>
    </head>
    <body onload="startGame()">
    <script>

    var myGamePiece;
    var myObstacles = [];
    var myScore;

    function startGame() {
        myGamePiece = new component(30, 30, "red", 10, 120, "img", "https://www.spreadshirt.ca/image-server/v1/mp/designs/12679277,width=178,height=178/red-flappy-bird.png");
        myGamePiece.gravity = 0;
        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 = 270;
            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, src) {
        this.type = type;
        this.src = src;
        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 == "text") {
                ctx.font = this.width + " " + this.height;
                ctx.fillStyle = color;
                ctx.fillText(this.text, this.x, this.y);
            } else if (this.type == "img") {
                var img=document.createElement('img');
                img.src=src;
                
                ctx.drawImage(img, 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;
            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 = 50;
            maxGap = 200;
            gap = Math.floor(Math.random()*(maxGap-minGap+1)+minGap);
            myObstacles.push(new component(10, height, "green", x, 0));
            myObstacles.push(new component(10, 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 move(n) {
        myGamePiece.gravity = n;   
    }

    function stopMove() {
        myGamePiece.gravity = 0;      
    }

    </script>
    <br>
    <!--<button onmousedown="accelerate(-0.2)" onmouseup="accelerate(0.05)">ACCELERATE</button>-->
    <button onmousedown="move(-0.2)" onmouseup="stopMove()">^</button>
    <button onmousedown="move(0.2)" onmouseup="stopMove()">v</button>
    <p>Use the ACCELERATE button to stay in the air</p>
    <p>How long can you stay alive?</p>
    </body>
    </html>

＆＃13;

你能帮我把这个游戏中的红色方块改成图像吗？

2 个答案: