很久很久以前的一个很流行的java Applet放烟花效果,当初移到android过,这次摸鱼时间翻译成js代码,用canvas实现
这么多年,终于能大致看懂这代码了,
已经实现透明效果,只需要给body弄个好看的背景图片就行,但需要主色为深色,看到的人谁有兴趣美化下,弄个背景加个声音啥的,不过没啥用就是的了,只是弄着好玩
谁要是弄得漂亮也给我看下,虽然我已经是个老头了,但也有一颗爱美的心
主要学到的是
1. js里面的各种Array,https://developer.mozilla.org/zh-CN/docs/Web/JavaScript/Reference/Global_Objects/Uint8ClampedArray
2. java中,像素数组一般用int数组,一个int表示一个像素, 而js中一般用Uint8数组,四个uint8表示一个像素,转换要考虑高低位的问题, 这里getPix setPix中的转换过程 可以省略掉,但年纪大了,懒了
【感谢GPT的大力相助】
index.html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1.0">
<title>烟花</title>
<style>
#mainCanvas{
width: 800px;
height: 600px;
background-color: rgba(255, 255, 255, 0);
position: absolute;
top: 0;
left: 0;
}
</style>
<script src="fireworks.js"></script>
</head>
<body style="background: #000000 ;">
<canvas ref="mainCanvas" id="mainCanvas" ></canvas>
<script>
var f=new Fireworks(mainCanvas);
</script>
</body>
</html>
Fireworks.js
class Fireworks{
constructor(canvas) {
//0xff000000前面的ff表示透明度,可以调小让背景图显示出来 不过这里没研究清楚
this.alpha = 0xFF000000;
this.fps = 12;
this.canvas = canvas;
this.width = 800;
this.height = 600;
this.size= this.width*this.height;
//减2行,以免超出
this.size2=this.size-this.width*2;
this.canvas.width = this.width;
this.canvas.height = this.height;
this.ctx = canvas.getContext('2d');
this.imageData = this.ctx.createImageData(this.width, this.height);
this.canvas.addEventListener("mousedown", this.onDown.bind(this));
//最多烟花数量,炸一次算50个,也就是同时最多10个烟花在,
this.bits=500;
//炸开后的烟花数量
this.bit_max=50;
//炸开角度,但具体影响还不清楚
this.ru = 50;
this.rv = 50;
//中心点
this.m_centerX = Math.floor(this.width / 2);
this.m_centerY = Math.floor(this.height / 2);
//实际图像数据 每四个位置表示一个像素 R G B A
this.data=new ArrayBuffer(this.width*this.height*4);
this.dataView = new DataView(this.data);
//烟花计算数据
this.bit_px = new Array(this.bits).fill(0);
this.bit_py = new Array(this.bits).fill(0);
this.bit_vx = new Array(this.bits).fill(0);
this.bit_vy = new Array(this.bits).fill(0);
this.bit_sx = new Int32Array(this.bits).fill(0);
this.bit_sy = new Int32Array(this.bits).fill(0);
this.bit_l = new Int32Array(this.bits).fill(0);
this.bit_f = new Int32Array(this.bits).fill(0);
this.bit_p = new Int32Array(this.bits).fill(0);
this.bit_c = new Int32Array(this.bits).fill(0);
this.m_centerX = Math.floor(this.width / 2);
this.m_centerY = Math.floor(this.height / 2);
this.initData();
this.calculate();
}
initData(){
//最开始的时候给弄透明了
for(var i=0;i<this.size;i++){
this.dataView.setUint32(i*4,0x00000000,true);
}
this.imageData.data.set(new Uint8ClampedArray(this.dataView.buffer));
}
onDown(event){
this.m_mouseX = event.offsetX;
this.m_mouseY = event.offsetY;
let k = Math.floor(Math.random() * 256);
let l = Math.floor(Math.random() * 256);
let i1 = Math.floor(Math.random() * 256);
let j1 = (k << 16) | (l << 8) | i1 | this.alpha;
let k1 = 0;
console.log(this.bits);
console.log(this.bit_max);
for (let l1 = 0; l1 < this.bits; l1++) {
if (this.bit_f[l1] !== 0) {
continue;
}
this.bit_px[l1] = this.m_mouseX;
this.bit_py[l1] = this.m_mouseY;
let d = Math.random() * 6.2800000000000002;
let d1 = Math.random();
this.bit_vx[l1] = Math.sin(d) * d1;
this.bit_vy[l1] = Math.cos(d) * d1;
this.bit_l[l1] = Math.floor(Math.random() * 100) + 100;
this.bit_p[l1] = Math.floor(Math.random() * 3);
this.bit_c[l1] = j1;
this.bit_sx[l1] = this.m_mouseX;
this.bit_sy[l1] = this.height - 5;
this.bit_f[l1] = 2;
if (++k1 === this.bit_max) {
break;
}
}
//这里播放开始声音
//这里尝试点击后修改一个像素点的颜色
/* let pix=this.getPix(y*this.width+x);
console.log(pix);
this.setPix(y*this.width+x,0xffff00f0);
this.imageData.data.set(new Uint8ClampedArray(this.dataView.buffer)); */
}
getPix(byteOffset){
//获取像素点
return this.dataView.getUint32(byteOffset*4, true);
}
setPix(byteOffset,val){
this.dataView.setUint32(byteOffset*4,val,true);
}
bit_set(x,y,v){
//设置像素点
this.setPix(y * this.width + x,v);
}
fade(){
//全图慢慢扩散和淡化
for (let j = 0; j < this.size2; j++) {
//取四个点
const k = this.getPix(j);
//最后会是黑色,所以如果一个点的值是黑色,就可以不运算了
if(k==this.alpha){
this.setPix(j,0x00000000);
continue;
}
if(k==0x00000000){
continue;
}
//右边
const l = this.getPix(j+1);
//下一行的点
const i1 = this.getPix(j + this.width);
//下一行右边
const j1 = this.getPix(j + this.width + 1);
let i = (k & 0xff0000) >> 16;
let k1 = ((((l & 0xff0000) >> 16) - i) * 50 >> 8) + i;
i = (k & 0xff00) >> 8;
let l1 = ((((l & 0xff00) >> 8) - i) * 50 >> 8) + i;
i = k & 0xff;
let i2 = (((l & 0xff) - i) * 50 >> 8) + i;
i = (i1 & 0xff0000) >> 16;
let j2 = ((((j1 & 0xff0000) >> 16) - i) * 50 >> 8) + i;
i = (i1 & 0xff00) >> 8;
let k2 = ((((j1 & 0xff00) >> 8) - i) * 50 >> 8) + i;
i = i1 & 0xff;
let l2 = (((j1 & 0xff) - i) * 50 >> 8) + i;
let i3 = ((j2 - k1) * 50 >> 8) + k1;
let j3 = ((k2 - l1) * 50 >> 8) + l1;
let k3 = ((l2 - i2) * 50 >> 8) + i2;
let val = (i3 << 16) | (j3 << 8) | k3 | this.alpha;
this.setPix(j,val);
}
}
//计算烟花
rend() {
let flag2 = false;
for (let k = 0; k < this.bits; k++) {
switch (this.bit_f[k]) {
default:
break;
case 1:
this.bit_vy[k] += Math.random() / 50;
this.bit_px[k] += this.bit_vx[k];
this.bit_py[k] += this.bit_vy[k];
this.bit_l[k]--;
if (this.bit_l[k] === 0 || this.bit_px[k] < 0.0 || this.bit_py[k] < 0.0 || this.bit_px[k] > this.width || this.bit_py[k] > this.height - 3) {
this.bit_c[k] = this.alpha;
this.bit_f[k] = 0;
} else if (this.bit_p[k] === 0) {
if (Math.floor(Math.random() * 2) === 0) {
this.bit_set(Math.floor(this.bit_px[k]), Math.floor(this.bit_py[k]), -1);
}
} else {
this.bit_set(Math.floor(this.bit_px[k]), Math.floor(this.bit_py[k]), this.bit_c[k]);
}
break;
case 2:
//这里是飞行速度,
this.bit_sy[k] -= 10;
if (this.bit_sy[k] <= this.bit_py[k]) {
this.bit_f[k] = 1;
flag2 = true;
}
if (Math.floor(Math.random() * 20) === 0) {
let i = Math.floor(Math.random() * 2);
let j = Math.floor(Math.random() * 5);
this.bit_set(this.bit_sx[k] + i, this.bit_sy[k] + j, -1);
}
break;
}
}
if (flag2 ) {
//播放爆炸声音
}
}
calculate(){
this.fade();
this.rend();
this.imageData.data.set(new Uint8ClampedArray(this.dataView.buffer));
this.ctx.putImageData(this.imageData,0,0);
setTimeout(()=>{this.calculate()},50);
}
}
原始java代码
import java.applet.Applet;
import java.applet.AudioClip;
import java.awt.*;
import java.awt.image.MemoryImageSource;
import java.util.Random;
@SuppressWarnings("serial")
public class Test extends Applet implements Runnable {
public static void main(String[]args){
Test test=new Test();
test.init();
}
public Test() {
m_mouseX = 0;
m_mouseY = 0;
m_sleepTime = 5;
isError = false;
isInitialized = false;
rand = new Random();
bits = 50;
bit_px = new double[bits];
bit_py = new double[bits];
bit_vx = new double[bits];
bit_vy = new double[bits];
bit_sx = new int[bits];
bit_sy = new int[bits];
bit_l = new int[bits];
bit_f = new int[bits];
bit_p = new int[bits];
bit_c = new int[bits];
ru = 50;
rv = 50;
}
public void init() {
String s ="50";
if (s != null)
bits = Integer.parseInt(s);
s = "30";
if (s != null)
bit_max = Integer.parseInt(s);
s = "20";
if (s != null)
ru = Integer.parseInt(s);
s = "100";
if (s != null)
rv = Integer.parseInt(s);
s ="0";
if (s != null)
bit_sound = Integer.parseInt(s);
m_nAppX = getSize().width;
m_nAppY = getSize().height;
m_centerX = m_nAppX / 2;
m_centerY = m_nAppY / 2;
m_mouseX = m_centerX;
m_mouseY = m_centerY;
resize(m_nAppX, m_nAppY);
pixls = m_nAppX * m_nAppY;
pixls2 = pixls - m_nAppX * 2;
pix0 = new int[pixls];
offImage = new MemoryImageSource(m_nAppX, m_nAppY, pix0, 0, m_nAppX);
offImage.setAnimated(true);
dbImg = createImage(offImage);
for (int i = 0; i < pixls; i++)
pix0[i] = 0xff000000;
//sound1 = getAudioClip(getDocumentBase(), "firework.au");
//sound2 = getAudioClip(getDocumentBase(), "syu.au");
for (int j = 0; j < bits; j++)
bit_f[j] = 0;
isInitialized = true;
start();
}
private boolean stop;
public void run() {
while (!isInitialized)
try {
Thread.sleep(200L);
} catch (InterruptedException interruptedexception) {
}
do {
for (int j = 0; j < pixls2; j++) {
int k = pix0[j];
int l = pix0[j + 1];
int i1 = pix0[j + m_nAppX];
int j1 = pix0[j + m_nAppX + 1];
int i = (k & 0xff0000) >> 16;
int k1 = ((((l & 0xff0000) >> 16) - i) * ru >> 8) + i;
i = (k & 0xff00) >> 8;
int l1 = ((((l & 0xff00) >> 8) - i) * ru >> 8) + i;
i = k & 0xff;
int i2 = (((l & 0xff) - i) * ru >> 8) + i;
i = (i1 & 0xff0000) >> 16;
int j2 = ((((j1 & 0xff0000) >> 16) - i) * ru >> 8) + i;
i = (i1 & 0xff00) >> 8;
int k2 = ((((j1 & 0xff00) >> 8) - i) * ru >> 8) + i;
i = i1 & 0xff;
int l2 = (((j1 & 0xff) - i) * ru >> 8) + i;
int i3 = ((j2 - k1) * rv >> 8) + k1;
int j3 = ((k2 - l1) * rv >> 8) + l1;
int k3 = ((l2 - i2) * rv >> 8) + i2;
pix0[j] = i3 << 16 | j3 << 8 | k3 | 0xff000000;
}
rend();
offImage.newPixels(0, 0, m_nAppX, m_nAppY);
try {
Thread.sleep(m_sleepTime);
} catch (InterruptedException interruptedexception1) {
}
} while (!stop);
}
public void update(Graphics g) {
paint(g);
}
public void paint(Graphics g) {
g.drawImage(dbImg, 0, 0, this);
}
public void start() {
if (isError)
return;
isRunning = true;
if (runner == null) {
runner = new Thread(this);
runner.start();
}
}
@SuppressWarnings("deprecation")
public void stop() {
if (runner != null) {
runner.stop();
runner = null;
}
}
public boolean mouseMove(Event event, int i, int j) {
m_mouseX = i;
m_mouseY = j;
return true;
}
public boolean mouseDown(Event event, int i, int j) {
m_mouseX = i;
m_mouseY = j;
int k = (int) (rand.nextDouble() * 256D);
int l = (int) (rand.nextDouble() * 256D);
int i1 = (int) (rand.nextDouble() * 256D);
int j1 = k << 16 | l << 8 | i1 | 0xff000000;
int k1 = 0;
for (int l1 = 0; l1 < bits; l1++) {
if (bit_f[l1] != 0)
continue;
bit_px[l1] = m_mouseX;
bit_py[l1] = m_mouseY;
double d = rand.nextDouble() * 6.2800000000000002D;
double d1 = rand.nextDouble();
bit_vx[l1] = Math.sin(d) * d1;
bit_vy[l1] = Math.cos(d) * d1;
bit_l[l1] = (int) (rand.nextDouble() * 100D) + 100;
bit_p[l1] = (int) (rand.nextDouble() * 3D);
bit_c[l1] = j1;
bit_sx[l1] = m_mouseX;
bit_sy[l1] = m_nAppY - 5;
bit_f[l1] = 2;
if (++k1 == bit_max)
break;
}
if (bit_sound > 1)
sound2.play();
return true;
}
public boolean mouseExit(Event event, int i, int j) {
m_mouseX = i;
m_mouseY = j;
return true;
}
// (JAVA世纪网,java2000.net)
void rend() {
boolean flag2 = false;
for (int k = 0; k < bits; k++)
switch (bit_f[k]) {
default:
break;
case 1: // '\001'
bit_vy[k] += rand.nextDouble() / 50D;
bit_px[k] += bit_vx[k];
bit_py[k] += bit_vy[k];
bit_l[k]--;
if (bit_l[k] == 0 || bit_px[k] < 0.0D || bit_py[k] < 0.0D || bit_px[k] > (double) m_nAppX
|| bit_py[k] > (double) (m_nAppY - 3)) {
bit_c[k] = 0xff000000;
bit_f[k] = 0;
} else if (bit_p[k] == 0) {
if ((int) (rand.nextDouble() * 2D) == 0)
bit_set((int) bit_px[k], (int) bit_py[k], -1);
} else {
bit_set((int) bit_px[k], (int) bit_py[k], bit_c[k]);
}
break;
case 2: // '\002'
bit_sy[k] -= 5;
if ((double) bit_sy[k] <= bit_py[k]) {
bit_f[k] = 1;
flag2 = true;
}
if ((int) (rand.nextDouble() * 20D) == 0) {
int i = (int) (rand.nextDouble() * 2D);
int j = (int) (rand.nextDouble() * 5D);
bit_set(bit_sx[k] + i, bit_sy[k] + j, -1);
}
break;
}
if (flag2 && bit_sound > 0)
sound1.play();
}
void bit_set(int i, int j, int k) {
int l = i + j * m_nAppX;
pix0[l] = k;
}
private int m_nAppX;
private int m_nAppY;
private int m_centerX;
private int m_centerY;
private int m_mouseX;
private int m_mouseY;
private int m_sleepTime;
private boolean isError;
boolean isRunning;
boolean isInitialized;
Thread runner;
int pix0[];
MemoryImageSource offImage;
Image dbImg;
int pixls;
int pixls2;
Random rand;
int bits;
double bit_px[];
double bit_py[];
double bit_vx[];
double bit_vy[];
int bit_sx[];
int bit_sy[];
int bit_l[];
int bit_f[];
int bit_p[];
int bit_c[];
int bit_max;
int bit_sound;
int ru;
int rv;
AudioClip sound1;
AudioClip sound2;
}