<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>在网页底部养鱼</title><link rel="stylesheet" href="./style.css">
</head>
<body>
<div id="fish-container" class="container"></div><script src='https://cdnjs.cloudflare.com/ajax/libs/jquery/3.6.0/jquery.min.js'></script><script src="./script.js"></script>
</body>
</html>
html, body{width: 100%;height: 100%;margin: 0;padding: 0;overflow: hidden;
}.container{width: 100%;height: 50%;transform: translateY(450px);margin: 0;padding: 0;background-color: #FFFFFF;
}
var RENDERER = {POINT_INTERVAL : 10,FISH_COUNT : 2,MAX_INTERVAL_COUNT : 40,INIT_HEIGHT_RATE : 0.5,THRESHOLD : 50,init : function(){this.setParameters();this.reconstructMethods();this.setup();this.bindEvent();this.render();},setParameters : function(){this.$window = $(window);this.$container = $('#fish-container');this.$canvas = $('<canvas />');this.context = this.$canvas.appendTo(this.$container).get(0).getContext('2d');this.points = [];this.fishes = [];this.watchIds = [];},createSurfacePoints : function(){var count = Math.round(this.width / this.POINT_INTERVAL);this.pointInterval = this.width / (count - 1);this.points.push(new SURFACE_POINT(this, 0));for(var i = 1; i < count; i++){var point = new SURFACE_POINT(this, i * this.pointInterval),previous = this.points[i - 1];point.setPreviousPoint(previous);previous.setNextPoint(point);this.points.push(point);}},reconstructMethods : function(){this.watchWindowSize = this.watchWindowSize.bind(this);this.jdugeToStopResize = this.jdugeToStopResize.bind(this);this.startEpicenter = this.startEpicenter.bind(this);this.moveEpicenter = this.moveEpicenter.bind(this);this.reverseVertical = this.reverseVertical.bind(this);this.render = this.render.bind(this);},setup : function(){this.points.length = 0;this.fishes.length = 0;this.watchIds.length = 0;this.intervalCount = this.MAX_INTERVAL_COUNT;this.width = this.$container.width();this.height = this.$container.height();this.fishCount = this.FISH_COUNT * this.width / 500 * this.height / 500;this.$canvas.attr({width : this.width, height : this.height});this.reverse = false;this.fishes.push(new FISH(this));this.createSurfacePoints();},watchWindowSize : function(){this.clearTimer();this.tmpWidth = this.$window.width();this.tmpHeight = this.$window.height();this.watchIds.push(setTimeout(this.jdugeToStopResize, this.WATCH_INTERVAL));},clearTimer : function(){while(this.watchIds.length > 0){clearTimeout(this.watchIds.pop());}},jdugeToStopResize : function(){var width = this.$window.width(),height = this.$window.height(),stopped = (width == this.tmpWidth && height == this.tmpHeight);this.tmpWidth = width;this.tmpHeight = height;if(stopped){this.setup();}},bindEvent : function(){this.$window.on('resize', this.watchWindowSize);this.$container.on('mouseenter', this.startEpicenter);this.$container.on('mousemove', this.moveEpicenter);this.$container.on('click', this.reverseVertical);},getAxis : function(event){var offset = this.$container.offset();return {x : event.clientX - offset.left + this.$window.scrollLeft(),y : event.clientY - offset.top + this.$window.scrollTop()};},startEpicenter : function(event){this.axis = this.getAxis(event);},moveEpicenter : function(event){var axis = this.getAxis(event);if(!this.axis){this.axis = axis;}this.generateEpicenter(axis.x, axis.y, axis.y - this.axis.y);this.axis = axis;},generateEpicenter : function(x, y, velocity){if(y < this.height / 2 - this.THRESHOLD || y > this.height / 2 + this.THRESHOLD){return;}var index = Math.round(x / this.pointInterval);if(index < 0 || index >= this.points.length){return;}this.points[index].interfere(y, velocity);},reverseVertical : function(){this.reverse = !this.reverse;for(var i = 0, count = this.fishes.length; i < count; i++){this.fishes[i].reverseVertical();}},controlStatus : function(){for(var i = 0, count = this.points.length; i < count; i++){this.points[i].updateSelf();}for(var i = 0, count = this.points.length; i < count; i++){this.points[i].updateNeighbors();}if(this.fishes.length < this.fishCount){if(--this.intervalCount == 0){this.intervalCount = this.MAX_INTERVAL_COUNT;this.fishes.push(new FISH(this));}}},render : function(){requestAnimationFrame(this.render);this.controlStatus();this.context.clearRect(0, 0, this.width, this.height);this.context.fillStyle = 'hsl(0, 0%, 0%)';for(var i = 0, count = this.fishes.length; i < count; i++){this.fishes[i].render(this.context);}this.context.save();this.context.globalCompositeOperation = 'xor';this.context.beginPath();this.context.moveTo(0, this.reverse ? 0 : this.height);for(var i = 0, count = this.points.length; i < count; i++){this.points[i].render(this.context);}this.context.lineTo(this.width, this.reverse ? 0 : this.height);this.context.closePath();this.context.fill();this.context.restore();}
};
var SURFACE_POINT = function(renderer, x){this.renderer = renderer;this.x = x;this.init();
};
SURFACE_POINT.prototype = {SPRING_CONSTANT : 0.03,SPRING_FRICTION : 0.8,WAVE_SPREAD : 0.3,ACCELARATION_RATE : 0.01,init : function(){this.initHeight = this.renderer.height * this.renderer.INIT_HEIGHT_RATE;this.height = this.initHeight;this.fy = 0;this.force = {previous : 0, next : 0};},setPreviousPoint : function(previous){this.previous = previous;},setNextPoint : function(next){this.next = next;},interfere : function(y, velocity){this.fy = this.renderer.height * this.ACCELARATION_RATE * ((this.renderer.height - this.height - y) >= 0 ? -1 : 1) * Math.abs(velocity);},updateSelf : function(){this.fy += this.SPRING_CONSTANT * (this.initHeight - this.height);this.fy *= this.SPRING_FRICTION;this.height += this.fy;},updateNeighbors : function(){if(this.previous){this.force.previous = this.WAVE_SPREAD * (this.height - this.previous.height);}if(this.next){this.force.next = this.WAVE_SPREAD * (this.height - this.next.height);}},render : function(context){if(this.previous){this.previous.height += this.force.previous;this.previous.fy += this.force.previous;}if(this.next){this.next.height += this.force.next;this.next.fy += this.force.next;}context.lineTo(this.x, this.renderer.height - this.height);}
};
var FISH = function(renderer){this.renderer = renderer;this.init();
};
FISH.prototype = {GRAVITY : 0.4,init : function(){this.direction = Math.random() < 0.5;this.x = this.direction ? (this.renderer.width + this.renderer.THRESHOLD) : -this.renderer.THRESHOLD;this.previousY = this.y;this.vx = this.getRandomValue(4, 10) * (this.direction ? -1 : 1);if(this.renderer.reverse){this.y = this.getRandomValue(this.renderer.height * 1 / 10, this.renderer.height * 4 / 10);this.vy = this.getRandomValue(2, 5);this.ay = this.getRandomValue(0.05, 0.2);}else{this.y = this.getRandomValue(this.renderer.height * 6 / 10, this.renderer.height * 9 / 10);this.vy = this.getRandomValue(-5, -2);this.ay = this.getRandomValue(-0.2, -0.05);}this.isOut = false;this.theta = 0;this.phi = 0;},getRandomValue : function(min, max){return min + (max - min) * Math.random();},reverseVertical : function(){this.isOut = !this.isOut;this.ay *= -1;},controlStatus : function(context){this.previousY = this.y;this.x += this.vx;this.y += this.vy;this.vy += this.ay;if(this.renderer.reverse){if(this.y > this.renderer.height * this.renderer.INIT_HEIGHT_RATE){this.vy -= this.GRAVITY;this.isOut = true;}else{if(this.isOut){this.ay = this.getRandomValue(0.05, 0.2);}this.isOut = false;}}else{if(this.y < this.renderer.height * this.renderer.INIT_HEIGHT_RATE){this.vy += this.GRAVITY;this.isOut = true;}else{if(this.isOut){this.ay = this.getRandomValue(-0.2, -0.05);}this.isOut = false;}}if(!this.isOut){this.theta += Math.PI / 20;this.theta %= Math.PI * 2;this.phi += Math.PI / 30;this.phi %= Math.PI * 2;}this.renderer.generateEpicenter(this.x + (this.direction ? -1 : 1) * this.renderer.THRESHOLD, this.y, this.y - this.previousY);if(this.vx > 0 && this.x > this.renderer.width + this.renderer.THRESHOLD || this.vx < 0 && this.x < -this.renderer.THRESHOLD){this.init();}},render : function(context){context.save();context.translate(this.x, this.y);context.rotate(Math.PI + Math.atan2(this.vy, this.vx));context.scale(1, this.direction ? 1 : -1);context.beginPath();context.moveTo(-30, 0);context.bezierCurveTo(-20, 15, 15, 10, 40, 0);context.bezierCurveTo(15, -10, -20, -15, -30, 0);context.fill();context.save();context.translate(40, 0);context.scale(0.9 + 0.2 * Math.sin(this.theta), 1);context.beginPath();context.moveTo(0, 0);context.quadraticCurveTo(5, 10, 20, 8);context.quadraticCurveTo(12, 5, 10, 0);context.quadraticCurveTo(12, -5, 20, -8);context.quadraticCurveTo(5, -10, 0, 0);context.fill();context.restore();context.save();context.translate(-3, 0);context.rotate((Math.PI / 3 + Math.PI / 10 * Math.sin(this.phi)) * (this.renderer.reverse ? -1 : 1));context.beginPath();if(this.renderer.reverse){context.moveTo(5, 0);context.bezierCurveTo(10, 10, 10, 30, 0, 40);context.bezierCurveTo(-12, 25, -8, 10, 0, 0);}else{context.moveTo(-5, 0);context.bezierCurveTo(-10, -10, -10, -30, 0, -40);context.bezierCurveTo(12, -25, 8, -10, 0, 0);}context.closePath();context.fill();context.restore();context.restore();this.controlStatus(context);}
};$(function(){RENDERER.init();
});