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webgl-translate.html
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webgl-translate.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>图形平移，缩放，旋转</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');
//attribute只传递顶点数量
// const VERTEX_SHADER_SOURCE = `
// attribute vec4 aPosition;
// attribute float aPointSize;
// attribute float aX;
// void main(){
// gl_Position=vec4(aPosition.x+aX,aPosition.y,aPosition.z,1.0);
// gl_PointSize=aPointSize;
// }
// `; //顶点-平移
// const VERTEX_SHADER_SOURCE = `
// attribute vec4 aPosition;
// attribute float aPointSize;
// attribute float aX;
// void main(){
// gl_Position=vec4(aPosition.x*aX,aPosition.y,aPosition.z,1.0);
// gl_PointSize=aPointSize;
// }
// `; //顶点-缩放
const VERTEX_SHADER_SOURCE = `
attribute vec4 aPosition;
attribute float aPointSize;
attribute float deg;
void main(){
gl_Position.x=aPosition.x*cos(deg)-aPosition.y*sin(deg);
gl_Position.y=aPosition.x*sin(deg)+aPosition.y*cos(deg);
gl_Position.z=aPosition.z;
gl_Position.w=aPosition.w;
gl_PointSize=aPointSize;
}
`; //顶点-旋转
const FRAGMENT_SHADER_SOURCE2 = `
precision mediump float;
uniform vec2 uColor;
void main(){
gl_FragColor=vec4(uColor.r,uColor.g,0.0,1.0);
}
`;//片元，uniform统一声明，所有点颜色一样
const program = initShader(gl, VERTEX_SHADER_SOURCE, FRAGMENT_SHADER_SOURCE2);
const aPosition = gl.getAttribLocation(program, 'aPosition');//第二个参数是源码里attribute声明的变量名
const aPointSize = gl.getAttribLocation(program, 'aPointSize');
const deg = gl.getAttribLocation(program, 'deg');
const uColor = gl.getUniformLocation(program, 'uColor');
gl.uniform2f(uColor, 1.0, 1.0);
//用类型化数组创建顶点数据，合并顶点location和size
const points = new Float32Array([
-0.5, -0.5, 0.0, 1.0, 10.0,
0.5, -0.5, 0.0, 1.0, 20.0,
// 0.0, 0.5, 30.0,
-0.5, 0.5, 0.0, 1.0, 30.0,
0.5, 0.5, 0.0, 1.0, 20.0,
// 0.5, 0.8, 10.0,
// 0.8, 0.5, 10.0
]);
const buffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
gl.bufferData(gl.ARRAY_BUFFER, points, gl.STATIC_DRAW);
const BYTES = points.BYTES_PER_ELEMENT//获取属性字节数
gl.vertexAttribPointer(aPosition, 4, gl.FLOAT, false, BYTES * 5, 0);
void gl.enableVertexAttribArray(aPosition);
gl.vertexAttribPointer(aPointSize, 1, gl.FLOAT, false, BYTES * 5, BYTES * 4);
void gl.enableVertexAttribArray(aPointSize);
// gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
// 循环图形移动
// let x = -1;
// setInterval(() => {
// x += 0.1;
// if (x > 1.0) {
// x = -1;
// }
// gl.vertexAttrib1f(aX, x);
// gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
// }, 200);
// 循环图形放大
// let x = 1;
// setInterval(() => {
// x += 0.1;
// if (x > 2.0) {
// x = 1;
// }
// gl.vertexAttrib1f(aX, x);
// gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
// }, 200);
// 循环图形旋转
let x = 1;
// setInterval(() => {
// x += 0.1;
// gl.vertexAttrib1f(deg, x);
// gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
// }, 200);
//计时器处理图形动画不友好
function animation() {
x += 0.1;
// x += -0.1;
gl.vertexAttrib1f(deg, x);
gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
requestAnimationFrame(animation);
}
animation();
</script>