とある既存のJavascriptを実際に自分の手で打ってみたのですが、どこを見直しても動きません。
自分で解決できなかったので、どこに問題があるかをご教授いただけますと幸いです。
完成すると雪のアニメーションが見られるみたいです。
HTML
1<!DOCTYPE html> 2<html lang="ja"> 3<head> 4 <meta charset="UTF-8"> 5 <meta http-equiv="X-UA-Compatible" content="IE=edge"> 6 <meta name="viewport" content="width=device-width, initial-scale=1.0"> 7 <title>雪のアニメーション</title> 8</head> 9<body> 10 <script src="ryan.js"></script> 11</body> 12</html>
JavaScript
1var canvas = document.querySelector('.snow'), 2ctx = canvas.getContext('2d'), 3windowW = window.innerWidth, 4windowH = window.innerHeight, 5numFlakes = 200, 6flakes = []; 7 8function Flake(x,y){ 9 var maxWeight = 5, 10 maxSpeed = 3; 11 12 13this.x = x; 14this.y = y; 15this.r = randomBetween(0,1), 16this.a = randomBetween(0,Math.PI); 17this.aStep = 0.01; 18 19this.weight = randomBetween(2,maxWeight); 20this.alpha = (this.weight/maxWeight); 21this.speed = (this.weight/maxWeight) * maxSpeed; 22 23this.update = function(){ 24 this.x += Math.cos(this.a)* this.r; 25 this.a += this.aStep; 26 27 this.y += this.speed; 28} 29 30} 31 32function init(){ 33 var i = numFlakes, 34 flake, 35 x, 36 y; 37 38 while(i--){ 39 x = randomBetween(0,windowW,true); 40 y = randomBetween(0,windowH,true); 41 42 flake = new Flake(x,y); 43 flakes.push(flake); 44 } 45 46 scaleCanvas(); 47 loop; 48} 49 50function scaleCanvas(){ 51 canvas.width = windowW; 52 canvas.height = windowH; 53} 54 55function loop(){ 56 var i = flakes.length, 57 z, 58 dist, 59 flakeA; 60 flakeB; 61 62 // clear canvas 63 ctx.save(); 64 ctx.setTransform(1,0,0,1,0,0); 65 ctx.clearRect(0,0,windowW,windowH); 66 ctx.restore(); 67 68 //loop of hell 69 while(i--){ 70 71 flakeA = flakes[i]; 72 flakeA.update(); 73 74 ctx.beginPath(); 75 ctx.arc(flakeA.x,flakeA.y,flakeA.weight,0,2*Math.PI,false); 76 ctx.fillStyle = 'rgba(255,255,255)' + flakeA.alpha + ')'; 77 ctx.fill(); 78 79 if(flakeA.y >= windowH){ 80 flakeA.y = -flakeA.weight; 81 } 82 } 83 84 requestAnimationFrame(loop); 85 } 86 87 function randomBetween(min,max,round){ 88 var num = Math.random() *(max - min + 1) + min; 89 90 if(round){ 91 return Math.floor(num); 92 }else{ 93 return num; 94 } 95 } 96 function distanceBetween(vector1,vector2){ 97 var dx = vector2.x - vector1.x, 98 dy = vector2.y - vector1.y; 99 100 return Math.sqrt(dx*dx + dy*dy); 101 } 102 103 init(); 104 var canvas = document.querySelector('.snow'), 105 ctx = canvas.getContext('2d'), 106 windowW = window.innerWidth, 107 windowH = window.innerHeight, 108 numFlakes = 200, 109 flakes = []; 110 111 function Flake(x,y){ 112 var maxWeight = 5, 113 maxSpeed = 3; 114 115this.x = x; 116this.y = y; 117this.r = randomBetween(0,1), 118this.a = randomBetween(0,Math.PI); 119this.aStep = 0.01; 120 121this.weight = randomBetween(2,maxWeight); 122this.alpha = (this.weight/maxWeight); 123this.speed = (this.weight/maxWeight) * maxSpeed; 124 125this.update = function(){ 126 this.x += Math.cos(this.a)* this.r; 127 this.a += this.aStep; 128 129 this.y += this.speed; 130 } 131 132} 133 134function init(){ 135 var i = numFlakes, 136 flake, 137 x, 138 y; 139 140 while(i--){ 141 x = randomBetween(0,windowW,true); 142 y = randomBetween(0,windowH,true); 143 144 flake = new Flake(x,y); 145 flakes.push(flake); 146 } 147 scaleCanvas(); 148 loop(); 149} 150 151function scaleCanvas(){ 152 canvas.width = windowW; 153 canvas.height = windowH; 154} 155 156function loop(){ 157 var i = flakes.length, 158 z, 159 dist, 160 flakeA, 161 flakeB; 162 163 ctx.save(); 164 ctx.setTransform(1,0,0,1,0,0); 165 ctx.clearRect(0,0,windowW,windowH); 166 ctx.restore(); 167 168 while(i--){ 169 flakeA = flakes[i]; 170 flakeA.update(); 171 172 173 ctx.beginPath(); 174 ctx.arc(flakeA.x,flakeA.y,flakeA.weight,0,2*Math.PI,false); 175 ctx.fillStyle = 'rgba(255,255,255)' + flakeA.alpha + ')'; 176 ctx.fill(); 177 178 if(flakeA.y >= windowH){ 179 flakeA.y = -flakeA.weight; 180 } 181 } 182 183 requestAnimationFrame(loop); 184 } 185 186 function randomBetween(min,max,round){ 187 var num = Math.random() *(max - min + 1) + min; 188 189 if(round){ 190 return Math.floor(num); 191 }else{ 192 return num; 193 } 194} 195 196function distanceBetween(vector1,vector2){ 197 var dx = vector2.x - vector1.x, 198 dy = vector2.y - vector1.y; 199 200 return Math.sqrt(dx*dx + dy*dy); 201} 202 203init(); 204 205
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2022/08/07 06:40