烟花特效

 //烟花特效
    class Circle {
        constructor({origin, speed, color, angle, context}) {
            this.origin = origin
            this.position = {...this.origin}
            this.color = color
            this.speed = speed
            this.angle = angle
            this.context = context
            this.renderCount = 0
        }

        draw() {
            this.context.fillStyle = this.color
            this.context.beginPath()
            this.context.arc(this.position.x, this.position.y, 2, 0, Math.PI * 2)
            this.context.fill()
        }

        move() {
            this.position.x = (Math.sin(this.angle) * this.speed) + this.position.x
            this.position.y = (Math.cos(this.angle) * this.speed) + this.position.y + (this.renderCount * 0.3)
            this.renderCount++
        }
    }

    class Boom {
        constructor({origin, context, circleCount = 10, area}) {
            this.origin = origin
            this.context = context
            this.circleCount = circleCount
            this.area = area
            this.stop = false
            this.circles = []
        }

        randomArray(range) {
            const length = range.length
            const randomIndex = Math.floor(length * Math.random())
            return range[randomIndex]
        }

        randomColor() {
            const range = ['8', '9', 'A', 'B', 'C', 'D', 'E', 'F']
            return '#' + this.randomArray(range) + this.randomArray(range) + this.randomArray(range) + this.randomArray(range) + this.randomArray(range) + this.randomArray(range)
        }

        randomRange(start, end) {
            return (end - start) * Math.random() + start
        }

        init() {
            for (let i = 0; i < this.circleCount; i++) {
                const circle = new Circle({
                    context: this.context,
                    origin: this.origin,
                    color: this.randomColor(),
                    angle: this.randomRange(Math.PI - 1, Math.PI + 1),
                    speed: this.randomRange(1, 6)
                })
                this.circles.push(circle)
            }
        }

        move() {
            this.circles.forEach((circle, index) => {
                if (circle.position.x > this.area.width || circle.position.y > this.area.height) {
                    return this.circles.splice(index, 1)
                }
                circle.move()
            })
            if (this.circles.length == 0) {
                this.stop = true
            }
        }

        draw() {
            this.circles.forEach(circle => circle.draw())
        }
    }

    class CursorSpecialEffects {
        constructor() {
            this.computerCanvas = document.createElement('canvas')
            this.renderCanvas = document.createElement('canvas')

            this.computerContext = this.computerCanvas.getContext('2d')
            this.renderContext = this.renderCanvas.getContext('2d')

            this.globalWidth = window.innerWidth
            this.globalHeight = window.innerHeight

            this.booms = []
            this.running = false
        }

        handleMouseDown(e) {
            const boom = new Boom({
                origin: {x: e.clientX, y: e.clientY},
                context: this.computerContext,
                area: {
                    width: this.globalWidth,
                    height: this.globalHeight
                }
            })
            boom.init()
            this.booms.push(boom)
            this.running || this.run()
        }

        handlePageHide() {
            this.booms = []
            this.running = false
        }

        init() {
            const style = this.renderCanvas.style
            style.position = 'fixed'
            style.top = style.left = 0
            style.zIndex = '999999999999999999999999999999999999999999'
            style.pointerEvents = 'none'

            style.width = this.renderCanvas.width = this.computerCanvas.width = this.globalWidth
            style.height = this.renderCanvas.height = this.computerCanvas.height = this.globalHeight

            document.body.append(this.renderCanvas)

            window.addEventListener('mousedown', this.handleMouseDown.bind(this))
            window.addEventListener('pagehide', this.handlePageHide.bind(this))
        }

        run() {
            this.running = true
            if (this.booms.length == 0) {
                return this.running = false
            }

            requestAnimationFrame(this.run.bind(this))

            this.computerContext.clearRect(0, 0, this.globalWidth, this.globalHeight)
            this.renderContext.clearRect(0, 0, this.globalWidth, this.globalHeight)

            this.booms.forEach((boom, index) => {
                if (boom.stop) {
                    return this.booms.splice(index, 1)
                }
                boom.move()
                boom.draw()
            })
            this.renderContext.drawImage(this.computerCanvas, 0, 0, this.globalWidth, this.globalHeight)
        }
    }

    try {
        module.exports.default = module.exports = CursorSpecialEffects
    } catch (err) {
        console.log("错误", err);
    }
    var yh = new CursorSpecialEffects();
    yh.init();//烟花特效

标签：origin,特效,style,烟花,range,context,position,Math
来源： https://www.cnblogs.com/huluxia-fun/p/15215930.html