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webgl-cone.html
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webgl-cone.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>3D圆锥展示</title>
<script src="./js/initShader.js"></script>
<script src="./js/matrix4.js"></script>
<style>
html,
body {
width: 100vw;
height: 100vh;
padding: 0;
margin: 0;
display: flex;
justify-content: center;
align-items: center;
}
</style>
</head>
<body>
<canvas id="webgl" width="400" height="400">浏览器不支持canvas</canvas>
</body>
</html>
<script type="module">
// 顶点着色器
const VERTEX_SHADER_SOURCE = `
attribute vec4 aPosition;
attribute vec4 aColor;
uniform mat4 uMvpMatrix;
varying vec4 vColor;
varying vec3 vNormal; // 用于贴图
void main(){
vec4 vertexPosition=uMvpMatrix*aPosition;
gl_Position=vertexPosition;
vColor=aColor;
// 传递法向量。因为位置是以几何中心为原点的
vNormal = normalize(aPosition.xyz);
}
`;
// 片元着色器
const FRAGMENT_SHADER_SOURCE = `
precision mediump float;
varying vec4 vColor;
uniform samplerCube uSampler;
varying vec3 vNormal;
void main(){
gl_FragColor=vColor;
// gl_FragColor=textureCube(uSampler, normalize(vNormal));
}
`;
function initVertexBuffers(gl) {
let radius = 0.3;
let height = 1;
let divideNum = 60; // 自定义几份数据
let theta = Math.PI * 2 / divideNum; // 一个圆2Π是360°
/**
* 4
* / \
* 3 1
* \ /
* \ 2 /
* \ /
* 0
*/
let vertices = [0, -height / 2, 0];
// let vertices = [];
for (let i = 0; i < divideNum; i++) {
let x = radius * Math.cos(theta * i);
let z = radius * Math.sin(theta * i);
vertices.push(x, height / 2, z);
}
let colors = [];
let baseColor = [[1.0, 0.4, 0.4], [0.4, 1.0, 0.4], [0.4, 0.4, 1.0], [0.2, 0.4, 0.0], [0.4, 0.3, 0.8], [0.8, 1, 0.1]];
colors.push(1.0, 0.4, 0.4);
for (let i = 1; i < vertices.length; i++) {
// let color = baseColor[Math.floor(Math.random()*6)];
// colors = colors.concat(color);
colors.push(0.4, 1.0, 0.4);
}
let indices = [];
for (let i = 1; i <= divideNum; i++) {
if (i === divideNum) {
indices.push(0, i, 1);
} else {
indices.push(0, i, i + 1);
}
}
vertices = Float32Array.from(vertices);
colors = Float32Array.from(colors);
indices = Uint8Array.from(indices);
var indexBuffer = gl.createBuffer();
if (!indexBuffer)
return -1;
if (!initArrayBuffer(gl, program, vertices, 3, gl.FLOAT, 'aPosition'))
return -1;
if (!initArrayBuffer(gl, program, colors, 3, gl.FLOAT, 'aColor'))
return -1;
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, indexBuffer);
gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, indices, gl.STATIC_DRAW);
return indices.length;
}
function initArrayBuffer(gl, program, data, num, type, attribute) {
var buffer = gl.createBuffer();
if (!buffer) {
console.log('Failed to create the buffer object');
return false;
}
gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
gl.bufferData(gl.ARRAY_BUFFER, data, gl.STATIC_DRAW);
var a_attribute = gl.getAttribLocation(program, attribute);
if (a_attribute < 0) {
console.log('Failed to get the storage location of ' + attribute);
return false;
}
gl.vertexAttribPointer(a_attribute, num, type, false, 0, 0);
gl.enableVertexAttribArray(a_attribute);
return true;
}
function initTexture(gl, program) {
const uSampler = gl.getUniformLocation(program, 'uSampler');
let index = 0;
// 创建纹理对象
const texture = gl.createTexture();
// 翻转图片Y轴
gl.pixelStorei(gl.UNPACK_FLIP_Y_WEBGL, 1);
// 开启一个纹理单元
gl.activeTexture(gl[`TEXTURE${index}`]);//纹理编号
// 绑定纹理对象
gl.bindTexture(gl.TEXTURE_CUBE_MAP, texture);//（type,texture），type有两种gl.TEXTURE_2D,gl.TEXTURE_CUBE_MAP,texture纹理对象
// 配置纹理图像
const ctx = document.createElement("canvas").getContext("2d");
ctx.canvas.width = 128;
ctx.canvas.height = 128;
const faceInfos = [
{ target: gl.TEXTURE_CUBE_MAP_POSITIVE_X, faceColor: '#F00', textColor: '#0FF', text: '+X' },
{ target: gl.TEXTURE_CUBE_MAP_NEGATIVE_X, faceColor: '#FF0', textColor: '#00F', text: '-X' },
{ target: gl.TEXTURE_CUBE_MAP_POSITIVE_Y, faceColor: '#0F0', textColor: '#F0F', text: '+Y' },
{ target: gl.TEXTURE_CUBE_MAP_NEGATIVE_Y, faceColor: '#0FF', textColor: '#F00', text: '-Y' },
{ target: gl.TEXTURE_CUBE_MAP_POSITIVE_Z, faceColor: '#00F', textColor: '#FF0', text: '+Z' },
{ target: gl.TEXTURE_CUBE_MAP_NEGATIVE_Z, faceColor: '#F0F', textColor: '#0F0', text: '-Z' },
];
faceInfos.forEach((faceInfo) => {
const { target, faceColor, textColor, text } = faceInfo;
generateFace(ctx, faceColor, textColor, text);
// 上传画布到立方体贴图的每个面。
const level = 0;
const internalFormat = gl.RGBA;
const format = gl.RGBA;
const type = gl.UNSIGNED_BYTE;
// https://developer.mozilla.org/zh-CN/docs/Web/API/WebGLRenderingContext/texImage2D
gl.texImage2D(target, level, internalFormat, format, type, ctx.canvas);
});
gl.generateMipmap(gl.TEXTURE_CUBE_MAP);
gl.texParameteri(gl.TEXTURE_CUBE_MAP, gl.TEXTURE_MIN_FILTER, gl.LINEAR_MIPMAP_LINEAR);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
gl.enable(gl.CULL_FACE);
gl.enable(gl.DEPTH_TEST);
gl.uniform1i(uSampler, index);// 0为纹理编号
}
function generateFace(ctx, faceColor, textColor, text) {
const { width, height } = ctx.canvas;
ctx.fillStyle = faceColor;
ctx.fillRect(0, 0, width, height);
ctx.font = `${width * 0.7}px sans-serif`;
ctx.textAlign = 'center';
ctx.textBaseline = 'middle';
ctx.fillStyle = textColor;
ctx.fillText(text, width / 2, height / 2);
}
let rotationAngle = 0;
function draw() {
// 获取着色器变量
const uMvpMatrix = gl.getUniformLocation(program, 'uMvpMatrix');
// 设置视觉矩阵,三要素(视点,目标点,上方向)
rotationAngle += 1;
let eyex = 0;
let eyey = 2.0;
let eyez = 5.0;
const eye = [eyex, eyey, eyez];
const lookAt = [0.0, 0.0, 0.0];
const up = [0.0, 1.0, 0.0];
// 设置canvas的背景色
gl.clearColor(0.0, 0.0, 0.0, 1.0);
// 清理缓冲区
gl.clear(gl.COLOR_BUFFER_BIT);
// 开启隐藏面消除
gl.enable(gl.DEPTH_TEST);
// 开启半透明
// gl.enable(gl.BLEND);
// 设置半透明物体
// gl.blendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA);
// 贴纹理
// initTexture(gl, program);
var modelMatrix = new Matrix4() //创建模型矩阵
var viewMatrix = new Matrix4() //创建视图矩阵
var projMatrix = new Matrix4() //创建投影矩阵
var mvpMatrix = new Matrix4() //创建模型视图投影矩阵
modelMatrix.rotate(rotationAngle, 1.0, 1.0, 1.0) //设置模型矩阵,旋转
viewMatrix.setLookAt(...eye, ...lookAt, ...up) //设置视点、视线和上方向
projMatrix.setPerspective(30, canvas.width / canvas.height, 1, 100) //设置透视投影矩阵
mvpMatrix.set(projMatrix).multiply(viewMatrix).multiply(modelMatrix) //将模型矩阵、视图矩阵、投影矩阵相乘赋值给模型视图投影矩阵
gl.uniformMatrix4fv(uMvpMatrix, false, mvpMatrix.elements);
// 绘制
gl.drawElements(gl.TRIANGLES, n, gl.UNSIGNED_BYTE, 0);
// 动画
requestAnimationFrame(draw);
}
// 获取webgl上下文
const canvas = document.getElementById('webgl');
const gl = canvas.getContext('webgl');// 或getWebGLContext(canvas)
// 着色器
const program = initShader(gl, VERTEX_SHADER_SOURCE, FRAGMENT_SHADER_SOURCE);
// 顶点 颜色 索引缓冲区
const n = initVertexBuffers(gl);
// 绘制
draw();
</script>