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webgl-matrix.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>矩阵,圆角</title>
<script src="./js/initShader.js"></script>
<script src="./js/matrix.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;
uniform mat4 mat;
varying vec4 vPosition;
void main(){
// gl_Position=mat*aPosition;
gl_Position=aPosition;
vPosition=aPosition;
// gl_PointSize=aPointSize;
gl_PointSize=10.0;
}
`; //顶点
const FRAGMENT_SHADER_SOURCE = `
// precision mediump float;
precision lowp float;
uniform vec2 uColor;
varying vec4 vPosition;
uniform float radius; //自定义圆角半径
uniform float w;
uniform float h;
void setColor(float x, float y, vec2 target) {
float d = distance(vec2(target), vec2(x, y));
if (d > radius) {
discard;
} else {
gl_FragColor = vec4(1.0,0.0,0.0,1.0);
}
}
void main() {
float x = vPosition.x;
float y = vPosition.y;
// 左上边界，判断是否设置圆角
vec2 topLeft = vec2(-w + radius, h - radius);
// 右上
vec2 topRight = vec2(w - radius, h - radius);
// 左下
vec2 bottomLeft = vec2(-w + radius, -h + radius);
// 右下
vec2 bottomRight = vec2(w - radius, -h + radius);
if (x < topLeft.x && y > topLeft.y) {
setColor(x, y, topLeft);
} else if (x > topRight.x && y > topRight.y) {
setColor(x, y, topRight);
} else if (x < bottomLeft.x && y < bottomLeft.y) {
setColor(x, y, bottomLeft);
} else if (x > bottomRight.x && y < bottomRight.y) {
setColor(x, y, bottomRight);
} else {
gl_FragColor = vec4(1.0,0.0,0.0,1.0);
}
}
`;//片元，uniform统一声明，所有点颜色一样
const program = initShader(gl, VERTEX_SHADER_SOURCE, FRAGMENT_SHADER_SOURCE);
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 mat = gl.getUniformLocation(program, 'mat');
const uColor = gl.getUniformLocation(program, 'uColor');
const radius = gl.getUniformLocation(program, 'radius');
gl.uniform2f(uColor, 1.0, 1.0);
const w = gl.getUniformLocation(program, 'w');
const h = gl.getUniformLocation(program, 'h');
const size = 0.5;
gl.uniform1f(w, size);
gl.uniform1f(h, size);
//用类型化数组创建顶点数据，合并顶点location和size
const points = new Float32Array([
-size, -size, 0.0, 1.0, 10.0,
size, -size, 0.0, 1.0, 20.0,
// 0.0, 0.5, 30.0,
-size, size, 0.0, 1.0, 30.0,
size, size, 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.uniform1f(radius, 0.1);//注意顺序，保证在绘制之前
// gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
// let x = 0;
// function animation() {
// //平移
// // x += 0.01;
// // if(x>1){
// // x=-1;
// // }
// // const matrix=getTranslateMatrix(x,x);
// //缩放
// // x += 0.01;
// // if (x > 1.5) {
// // x = 0.1;
// // }
// // const matrix = getScaleMatrix(x,x);
// //旋转
// x += 0.01;
// const matrix = getRotateMatrix(x);
// gl.uniformMatrix4fv(mat, false, matrix);//(location,transpose,array)location对应uniform存储位置，transpose在webgl中恒为false，array矩阵数组
// gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
// requestAnimationFrame(animation);
// }
// animation();
const start = () => {
//这种不需要考虑执行顺序
gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
requestAnimationFrame(start)
}
start();
</script>