我在做游戏,但遇到一个问题。当他向左移动时,我需要反转角色,我不能只创建反转图像并使用它,也不能反转画布,因为我将拥有一些新角色并且它们不会反转。一种方法是引用我的角色CSS属性,并使用js添加类似以下内容:
-webkit-transform: scaleX(-1);
transform: scaleX(-1);
我可以在画布上这样做吗?
用箭头移动
var canvas = document.getElementById('canvas');
var context = canvas.getContext('2d');
var lifes = 700;
var fon = new Image();
fon.src = "https://i.stack.imgur.com/HjXpq.jpg";
var life_red = new Image();
life_red.src = "https://i.stack.imgur.com/sGZ7l.jpg";
var life_green = new Image();
life_green.src = "https://i.stack.imgur.com/9eWXX.jpg";
var iron_man_img = new Image(); // Player walking right
iron_man_img.src = 'https://i.stack.imgur.com/aeTtS.png';
var iron_man = {
x: 300,
y: 50,
dx: 100,
dy: 0.1,
dfly: 500,
run: 0, //animation
runspeed: 5, // animation speed
fly: false,
timeforflying: 0,
alive: true
}
var keys = {};
function setKey(event, status) {
var code = event.keyCode;
var key;
if (code == 32) {
key = "Space";
} else if (code == 37) {
key = "Left";
} else if (code == 38) {
key = "Up";
} else if (code == 39) {
key = "Right";
} else if (code == 40) {
key = "Down";
} else {
key = String.fromCharCode(code);
}
keys[key] = status;
}
document.addEventListener('keydown', function(e) {
setKey(e, true);
});
document.addEventListener('keyup', function(e) {
setKey(e, false);
});
document.addEventListener('blur', function() {
keys = {};
});
function isDown(key) {
return keys[key];
}
iron_man_img.onload = function() {
last = Date.now();
game();
}
function game() {
var now = Date.now();
var dt = (now - last) / 1000;
update(dt);
render();
last = now;
requestAnimFrame(game);
}
function update(dt) {
if (isDown("Right") || isDown("D")) {
iron_man.run += iron_man.runspeed * dt;
iron_man.x += iron_man.runspeed * dt * 10;
}
if (isDown("Left") || isDown("A")) {
iron_man.run += iron_man.runspeed * dt;
iron_man.x -= iron_man.runspeed * dt * 10;
}
//console.log(iron_man.runspeed * dt);
}
function render() {
var width = window.innerWidth;
var height = window.innerHeight;
//console.log(width/height);
//console.log(700/500);
if (width / height > 700 / 500) {
$('canvas').css('height', height);
$('canvas').css('width', height / 500 * 700);
} else {
$('canvas').css('width', width);
$('canvas').css('height', width / 700 * 500);
}
context.fillStyle = "green";
curr_life = new Image();
curr_life.src = "Sprites/life_green.jpg";
for (var i = 0; i < 1800; i++) { // HP
if (i == lifes) {
curr_life.src = "Sprites/life_red.jpg";
}
//context.drawImage(curr_life, 240, 268, i, 0, 1, 1);
context.drawImage(curr_life, i, 0, 10, 10);
}
if (lifes != 0) {
//lifes--;
}
context.drawImage(fon, 0, 0, 1000, 1000);
context.drawImage(iron_man_img, 44 * (Math.round(iron_man.run) % 8) + 1.2, 0, 44, 65, iron_man.x, iron_man.y, 50, 60);
//console.log(iron_man.run);
//iron_man.x+=1;
//iron_man.x+=1;
}
var requestAnimFrame = (function() {
return window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
window.oRequestAnimationFrame ||
window.msRequestAnimationFrame ||
function(callback) {
window.setTimeout(callback, 50);
};
})();
#canvas {
background-color: lightblue;
margin: 0 auto;
position: absolute;
top: 0;
left: 0;
bottom: 0;
right: 0;
display: block;
padding: 0;
}
body {
overflow: hidden;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.0.0/jquery.min.js"></script>
<div align="center" class="canvas-div">
<canvas id="canvas" width="700" height="500" style="border: 1px solid black" class="canvas">
Canvas is not working in your browser
</canvas>
</div>
答案 0 :(得分:1)
正确的是,最好的方法是使用画布比例尺,为了使其正常工作,必须进行一些更改,但是我将尽我所能来解释它们。
为了保持方向感,我添加了iron_man.z
并使用-1表示左侧,而1表示右侧,因为这是缩放的原理。
接下来,在update()
中,我们需要根据所按的键将iron_man.z
设置为1或-1。
现在输入复数位。在运行平移和缩放之前,我们运行context.save()
来记住所有设置。
我们必须转换以设置比例原点,我们希望原点成为钢铁侠的中心。要计算出我们执行iron_man.x + width / 2和iron_man.y + height / 2(context.translate(iron_man.x + 25, iron_man.y + 30)
),这意味着Ironman的位置也需要有所不同,但是我们需要先缩放。
对于规模,我们只需要iron_man.z
,所以我们有context.scale(iron_man.z,1)
。
最后我们绘制图像,因为将原点设置为钢铁侠的中心,所以我们需要将x和y坐标放在-(width / 2),-(height / 2)。
最后,我们要使用context.restore()
var canvas = document.getElementById('canvas');
var context = canvas.getContext('2d');
var lifes = 700;
var fon = new Image();
fon.src = "https://i.stack.imgur.com/HjXpq.jpg";
var life_red = new Image();
life_red.src = "https://i.stack.imgur.com/sGZ7l.jpg";
var life_green = new Image();
life_green.src = "https://i.stack.imgur.com/9eWXX.jpg";
var iron_man_img = new Image(); // Player walking right
iron_man_img.src = 'https://i.stack.imgur.com/aeTtS.png';
var iron_man = {
x: 300,
y: 50,
z: -1,
dx: 100,
dy: 0.1,
dfly: 500,
run: 0, //animation
runspeed: 5, // animation speed
fly: false,
timeforflying: 0,
alive: true
}
var keys = {};
function setKey(event, status) {
var code = event.keyCode;
var key;
if (code == 32) {
key = "Space";
console.log(iron_man)
} else if (code == 37) {
key = "Left";
} else if (code == 38) {
key = "Up";
} else if (code == 39) {
key = "Right";
} else if (code == 40) {
key = "Down";
} else {
key = String.fromCharCode(code);
}
keys[key] = status;
}
document.addEventListener('keydown', function(e) {
setKey(e, true);
});
document.addEventListener('keyup', function(e) {
setKey(e, false);
});
document.addEventListener('blur', function() {
keys = {};
});
function isDown(key) {
return keys[key];
}
iron_man_img.onload = function() {
last = Date.now();
game();
}
function game() {
var now = Date.now();
var dt = (now - last) / 1000;
update(dt);
render();
last = now;
requestAnimFrame(game);
}
function update(dt) {
if (isDown("Right") || isDown("D")) {
iron_man.run += iron_man.runspeed * dt;
iron_man.x += iron_man.runspeed * dt * 10;
iron_man.z = 1;
}
if (isDown("Left") || isDown("A")) {
iron_man.run += iron_man.runspeed * dt;
iron_man.x -= iron_man.runspeed * dt * 10;
iron_man.z = -1;
}
//console.log(iron_man.runspeed * dt);
}
function render() {
var width = window.innerWidth;
var height = window.innerHeight;
//console.log(width/height);
//console.log(700/500);
if (width / height > 700 / 500) {
$('canvas').css('height', height);
$('canvas').css('width', height / 500 * 700);
} else {
$('canvas').css('width', width);
$('canvas').css('height', width / 700 * 500);
}
context.fillStyle = "green";
curr_life = new Image();
curr_life.src = "Sprites/life_green.jpg";
for (var i = 0; i < 1800; i++) { // HP
if (i == lifes) {
curr_life.src = "Sprites/life_red.jpg";
}
//context.drawImage(curr_life, 240, 268, i, 0, 1, 1);
context.drawImage(curr_life, i, 0, 10, 10);
}
if (lifes != 0) {
//lifes--;
}
context.drawImage(fon, 0, 0, 1000, 1000);
context.save();
context.translate(iron_man.x + 25, iron_man.y + 30);
context.scale(iron_man.z, 1);
context.drawImage(iron_man_img, 44 * (Math.round(iron_man.run) % 8) + 1.2, 0, 44, 65, -25, -30, 50, 60);
context.restore();
//console.log(iron_man.run);
//iron_man.x+=1;
//iron_man.x+=1;
}
var requestAnimFrame = (function() {
return window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
window.oRequestAnimationFrame ||
window.msRequestAnimationFrame ||
function(callback) {
window.setTimeout(callback, 50);
};
})();
#canvas {
background-color: lightblue;
margin: 0 auto;
position: absolute;
top: 0;
left: 0;
bottom: 0;
right: 0;
display: block;
padding: 0;
}
body {
overflow: hidden;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.0.0/jquery.min.js"></script>
<div align="center" class="canvas-div">
<canvas id="canvas" width="700" height="500" style="border: 1px solid black" class="canvas">
Canvas is not working in your browser
</canvas>
</div>