Javascript-Canvas-Projects/hackerEffectBG.html at main · KalamPinjar/Javascript-Canvas-Projects · GitHub

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<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            padding: 0;
            margin: 0;
            box-sizing: border-box;
        }

        body {
            overflow: hidden;
            background: #000;
        }

        canvas {
            background: #000;
            position: absolute;
            top: 0;
            left: 0;
        }
    </style>
</head>

<body>
    <canvas id="canvas1"></canvas>


    <script>
        const canvas = document.getElementById('canvas1')
        const ctx = canvas.getContext('2d')
        canvas.width = window.innerWidth
        canvas.height = window.innerHeight

        let gradient = ctx.createRadialGradient(
            canvas.width / 2,
            canvas.height / 2,
            100,
            canvas.width / 2,
            canvas.height / 2, canvas.width / 2)

        gradient.addColorStop(0, 'magenta')
        gradient.addColorStop(0.5, 'cyan')
        gradient.addColorStop(1, 'red')

        class Symbol {
            constructor(x, y, fontSize, canvasHeight) {
                this.characters = `アァカサタナハマヤャラワガザダバパイィキシチニヒミリヰギジヂビピウゥクスツヌフムユュルグズブヅプエェケセテネヘメレヱゲゼデベペオォコソトノホモヨョロヲゴゾドボポヴッン0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ`
                this.x = x
                this.y = y
                this.text = ''
                this.fontSize = fontSize
                this.canvasHeight = canvasHeight
            }
            draw(context) {
                this.text = this.characters.charAt(Math.floor(Math.random() * this.characters.length))

                context.fillText(this.text, this.x * this.fontSize, this.y * this.fontSize)
                if (this.y * this.fontSize > this.canvasHeight &&
                    Math.random() > 0.98) {
                    this.y = 0
                }
                else {
                    this.y += 1
                }
            }


        }

        class Effect {
            constructor(canvasWidth, canvasHeight) {
                this.canvasWidth = canvasWidth
                this.canvasHeight = canvasHeight
                this.fontSize = 15
                this.columns = this.canvasWidth / this.fontSize
                this.symbols = []
                this.#initialize()
                console.log(this.symbols)
            }
            #initialize() {
                for (let i = 0; i < this.columns; i++) {
                    this.symbols[i] = new Symbol(i, 0, this.fontSize, this.canvasHeight)

                }

            } reSize(width, height) {
                this.canvasWidth = width
                this.canvasHeight = height
                this.columns = this.canvasWidth / this.fontSize
                this.symbols = []
                this.#initialize()
            }
        }

        const effect = new Effect(canvas.width, canvas.height)

        let lastTime = 0
        const fps = 30
        const nextFrame = 1000 / fps
        let timer = 0

        function animate(timeStamp) {
            const deltaTime = timeStamp - lastTime
            lastTime = timeStamp

            if (timer > nextFrame) {
                ctx.fillStyle = `rgb(0,0,0,0.08)`
                ctx.textAlign = 'center'
                ctx.fillRect(0, 0, canvas.width, canvas.height)
                // ctx.fillStyle = '#0aff0a '
                ctx.fillStyle = gradient
                ctx.font = effect.fontSize + `px monospace`
                effect.symbols.forEach(symbol => symbol.draw(ctx))
                timer = 0
            }
            else {
                timer += deltaTime
            }

            requestAnimationFrame(animate)
        }
        animate(0)

        window.addEventListener('resize', function () {

            canvas.width = window.innerWidth
            canvas.height = window.innerHeight
            effect.reSize(canvas.width, canvas.height)

            gradient = ctx.createRadialGradient(
                canvas.width / 2,
                canvas.height / 2,
                100,
                canvas.width / 2,
                canvas.height / 2, canvas.width / 2)

            gradient.addColorStop(0, 'magenta')
            gradient.addColorStop(0.5, 'cyan')
            gradient.addColorStop(1, 'red')
        })
    </script>
</body>

</html>