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webgl-snake.html
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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>webgl入门</title>
<script src="./js/initShader.js"></script>
<style>
html,
body {
width: 100vw;
height: 100vh;
padding: 0;
margin: 0;
display: flex;
justify-content: center;
align-items: center;
}
body::after {
content: '';
display: block;
width: 1px;
height: 500px;
background-color: aqua;
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
}
body::before {
content: '';
display: block;
width: 500px;
height: 1px;
background-color: darkviolet;
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
}
</style>
</head>
<body>
<canvas id="draw1" width="400" height="400" style="background: pink;">浏览器不支持canvas</canvas>
</body>
</html>
<script type="module">
const draw1 = document.getElementById('draw1');
const gl = draw1.getContext('webgl');
const VERTEX_SHADER_SOURCE = `
attribute vec4 aPosition;
void main(){
gl_Position=aPosition;
gl_PointSize=10.0;
}
`; //顶点
const FRAGMENT_SHADER_SOURCE = `
precision mediump float;
uniform vec2 uColor;
void main(){
gl_FragColor=vec4(uColor.r,uColor.g,0.0,1.0);
}
`;
const program = initShader(gl, VERTEX_SHADER_SOURCE, FRAGMENT_SHADER_SOURCE);
const aPosition = gl.getAttribLocation(program, 'aPosition');//第二个参数是源码里attribute声明的变量名
const uColor = gl.getUniformLocation(program, 'uColor');
gl.uniform2f(uColor, 1.0, 1.0);
//蛇身长度
let points = [{ x: 0, y: 0 }];
//食物的坐标
const random = {
isConnect: true,//判断是否更新食物坐标
};
//初始移动速度
let originSpeed = 0.02;
//行动速度
let speed = originSpeed;
//当前移动方向
let direction = 'x';
//允许吃掉食物的误差范围
let base = 1.5;
document.onkeydown = (e) => {
switch (e.keyCode) {
case 37:
//左
direction = 'x';
speed = -originSpeed;
break;
case 38:
//上
direction = 'y';
speed = originSpeed;
break;
case 39:
//右
direction = 'x';
speed = originSpeed;
break;
case 40:
//下
direction = 'y';
speed = -originSpeed;
break;
}
}
let timer = null;
function start() {
timer = setInterval(() => {
//边界判断
if (points[0].x > 1.0 || points[0].x < -1.0 || points[0].y > 1.0 || points[0].y < -1.0) {
alert('游戏结束');
restart();
}
if (points[0].x > random.x - base * originSpeed
&& points[0].x < random.x + base * originSpeed
&& points[0].y > random.y - base * originSpeed
&& points[0].y < random.y + base * originSpeed) {
points.push({ x: random.x, y: random.y }); //吃进食物，蛇身边长
random.isConnect = true;
}
createRandom();
draw();
}, 100)
}
start();
function restart() {
clearInterval(timer);
points = [{ x: 0, y: 0 }];
speed = originSpeed;
direction = 'x';
start();
}
function draw() {
gl.vertexAttrib2f(aPosition, random.x, random.y);
gl.drawArrays(gl.POINTS, 0, 1);
let prePoint = { ...points[0] };//保留上一个段身体的方向
for (const i in points) {
if (i == 0) {
points[0][direction] += speed;
} else {
points[i] = { ...prePoint };
points[i][direction] -= speed;
prePoint = { ...points[i]};
}
gl.vertexAttrib2f(aPosition, points[i].x, points[i].y);
gl.drawArrays(gl.POINTS, 0, 1);
}
}
function createRandom() {
if (random.isConnect) {
random.x = Math.random() * 2 - 1;
random.y = Math.random() * 2 - 1;
random.isConnect = false;
}
}
</script>