canvas多彩条纹效果代码
代码语言:html
所属分类:其他
代码描述:canvas多彩条纹效果代码
下面为部分代码预览,完整代码请点击下载或在bfwstudio webide中打开
<!DOCTYPE html>
<html lang="en" >
<head>
<meta charset="UTF-8">
<style>
body {
font-family: Arial, Helvetica, "Liberation Sans", FreeSans, sans-serif;
background-color: #fff;
margin: 0;
padding: 0;
border-width: 0;
}
</style>
</head>
<body >
<script >
"use strict";
window.addEventListener("load", function () {
let triWidth, triHeight; // length of triangle side and altitude
let canv, ctx; // canvas and context
let maxx, maxy; // canvas dimensions
let grid;
let nbx, nby;
let hnbx, hnby; // number of triangles in the half of the width, height of the canvas
let nbLines;
let events;
// shortcuts for Math.
const mrandom = Math.random;
const mfloor = Math.floor;
const mround = Math.round;
const mceil = Math.ceil;
const mabs = Math.abs;
const mmin = Math.min;
const mmax = Math.max;
const mPI = Math.PI;
const mPIS2 = Math.PI / 2;
const m2PI = Math.PI * 2;
const msin = Math.sin;
const mcos = Math.cos;
const matan2 = Math.atan2;
const mhypot = Math.hypot;
const msqrt = Math.sqrt;
const rac3 = msqrt(3);
const rac3s2 = rac3 / 2;
const mPIS3 = Math.PI / 3;
const sinPIS6 = 0.5;
const cosPIS6 = rac3s2;
const sinPIS3 = cosPIS6;
const cosPIS3 = sinPIS6;
//------------------------------------------------------------------------
function alea(mini, maxi) {
// random number in given range
if (typeof maxi == "undefined") return mini * mrandom(); // range 0..mini
return mini + mrandom() * (maxi - mini); // range mini..maxi
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
function intAlea(mini, maxi) {
// random integer in given range (mini..maxi - 1 or 0..mini - 1)
//
if (typeof maxi == "undefined") return mfloor(mini * mrandom()); // range 0..mini - 1
return mini + mfloor(mrandom() * (maxi - mini)); // range mini .. maxi - 1
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
function removeElement(array, element) {
let idx = array.indexOf(element);
array.splice(idx, 1);
} // removeElement
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
function randomElement(array) {
return array[intAlea(0, array.length)];
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
function arrayShuffle(array) {
/* randomly changes the order of items in an array
only the order is modified, not the elements
*/
let k1, temp;
for (let k = array.length - 1; k >= 1; --k) {
k1 = intAlea(0, k + 1);
temp = array[k];
array[k] = array[k1];
array[k1] = temp;
} // for k
return array;
} // arrayShuffle
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
/* returns lerp point between p0 and p1,
alpha = 0 will return p0, alpha = 1 will return p1
values of alpha outside [0,1] may be used to compute points outside the p0-p1 segment
*/
function lerp(p0, p1, alpha) {
return {
x: (1 - alpha) * p0.x + alpha * p1.x,
y: (1 - alpha) * p0.y + alpha * p1.y };
} // function lerp
//------------------------------------------------------------------------
class Triangle {
constructor(kx, ky) {
/* numbering of vertices / edges
0 2---1---1
/ \ \ /
2 0 2 0
/ \ \ /
2---1---1 0
*/
/* constructor */
this.kx = kx;
this.ky = ky;
this.kxc = kx - hnbx;
this.kyc = ky - hnby;
this.upsideDown = this.kxc + this.kyc & 1; // 0 or 1
this.setXY();
} // constructor
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
setBase(side) {
// where side is 0,1,2
this.base = side; // which side is the base ?
this.dirBase = [
[0, 1, 2],
[2, 1, 0]][
this.upsideDown][this.base]; // orientation of base (== base side number for normally oriented triangle)
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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