wewindy

with temp_result as (
	select st_point(1, 2) as test_point
)
select st_asgeojson(test_point) as final_result from temp_result;

wewindy

uniform sampler2D Tex;
const float size = 0.5;  

void main(void)
{  
  vec2 realSize = vec2(textureSize(Tex, 0));  
  float ratio = (realSize.x > realSize.y) ? realSize.y/realSize.x : realSize.x/realSize.y;  
  
  vec2 texSize = vec2(512., 512.);
  vec2 xy = gl_FragCoord.xy;

wewindy

import { Color, defined, Event, Material, Property } from 'cesium'

const PolylineTrailLinkType = 'PolylineTrailLink'

const PolylineTrailLinkSource = /* glsl */`
czm_material czm_getMaterial(czm_materialInput materialInput) 
{
  czm_material material = czm_getDefaultMaterial(materialInput);
  vec2 st = materialInput.st;

wewindy

<button id="btn">ClickMe</button>
<script>
  const btn = document.getElementById('btn')
  let fileHandle
  btn.addEventListener('click', async () => {
    [fileHandle] = await window.showOpenFilePicker()
    const file = await fileHandle.getFile()
    const contents = await file.text()
    console.log(contents)
  })

wewindy

使用a标签的 click 事件以及 URL.createObjectURL 方法 适合小文件的下载（无后端）

保存二进制文件

const buffer = new Float32Array([1, 2, 3, 4, 5]) // 创建一个类型数组，大小为 20 bytes
// 创建 blob 对象，第一个参数可以放置多个变量，这里放一个就好了
const blob = new Blob([buffer], {
 type: "application/octet-stream"

wewindy

function main() {
  let last = 0
  // 上次渲染的值(此处初始化为一个整数)
  let lastState = Math.floor(Math.random() * 10)
  const canWeRender = function() {
    // 这次渲染的值
    const currentState = Math.floor(Math.random() * 10)
    // 比较二者是否一致，如果一致，则false，否则true
    if (currentState === lastState) {
      console.log("lastState eq. currentState. Will not render.")

wewindy

function friendlyFileSize(sizeInBytes) {
  if(sizeInBytes < 1024) {
    return `${sizeInBytes} Bytes`;
  } else if(sizeInBytes >= 1024 && sizeInBytes < 1048576) {
    return `${(sizeInBytes/1024).toFixed(2)} KB`;
  } else if(sizeInBytes >= 1048576) {
    return `${(sizeInBytes/1048576).toFixed(2)} MB`;
  }
}

wewindy

import localForage from 'localforage'

// 创建仓库对象，并创建名为 “test” 的 indexeddb 以及 名为 “testidb” 的表
const store = localForage.createInstance({
  driver: localForage.INDEXEDDB,
  name: "test",
  storeName: "testidb"
})

// 设置 key-value

wewindy

import Matrix2 from '../core/mat2.js'
import Matrix3, { transpose, multiply, } from '../core/mat3.js'

/**
 * 雅可比迭代法求解实对称矩阵的特征向量、特征值
 * @param {Matrix2 | Matrix3} matrix 二维数组，当前支持二维、三维迭代求解
 * @returns {Object} 返回一个对象 obj, obj.eigenVectors 是特征向量(二维数组)，obj.eigenValues 是特征值(一维数组)
 */
function jacobi(matrix) {
  const length = matrix.length === undefined ? matrix.dimensions : matrix.length

wewindy

/**
* 将矩阵（二维数组形式）转置的高效方法
* @param {Array[][]} arr 二维数组，子数组中元素个数应一致
*/
export function transpose(arr) {
  return arr[0].map((_, i) => arr.map(row => row[i]))
}