基于Sketch.js，实现了物体触碰检测（蝌蚪会遇到障碍物以及聪明的躲避鼠标的点击），随机运动，聚集算法等。
已经具备了游戏的基本要素，扩展一下可以变成一个不错的 HTML5 游戏。
演示效果如下：
完整代码如下：
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>HTML5 Preview Panel</title> <script src="https://www.jb51.net/prefixfree.min.js"></script> <script src="https://www.jb51.net/modernizr.js"></script> <style> body { background-color: #222; } </style> </head> <body> <script src="https://www.jb51.net/sketch.min.js"></script> <div> <canvas></canvas> </div> <script> var calculateDistance = function(object1, object2) { x = Math.abs(object1.x - object2.x); y = Math.abs(object1.y - object2.y); return Math.sqrt((x * x) + (y * y)); }; var calcMagnitude = function(x, y) { return Math.sqrt((x * x) + (y * y)); }; var calcVectorAdd = function(v1, v2) { return { x: v1.x + v2.x, y: v1.y + v2.y }; }; var random = function(min, max) { return min + Math.random() * (max - min); }; var getRandomItem = function(list, weight) { var total_weight = weight.reduce(function(prev, cur, i, arr) { return prev + cur; }); var random_num = random(0, total_weight); var weight_sum = 0; //console.log(random_num) for (var i = 0; i < list.length; i++) { weight_sum += weight[i]; weight_sum = +weight_sum.toFixed(2); if (random_num <= weight_sum) { return list[i]; } } // end of function }; /*********************** BOID ***********************/ function Boid(x, y) { this.init(x, y); } Boid.prototype = { init: function(x, y) { //body this.type = "boid"; this.alive = true; this.health = 1; this.maturity = 4; this.speed = 6; this.size = 5; this.hungerLimit = 12000; this.hunger = 0; this.isFull = false; this.digestTime = 400; this.color = 'rgb(' + ~~random(0, 100) + ',' + ~~random(50, 220) + ',' + ~~random(50, 220) + ')'; //brains this.eyesight = 100; //range for object dectection this.personalSpace = 20; //distance to avoid safe objects this.flightDistance = 60; //distance to avoid scary objects this.flockDistance = 100; //factor that determines how attracted the boid is to the center of the flock this.matchVelFactor = 6; //factor that determines how much the flock velocity affects the boid. less = more matching this.x = x || 0.0; this.y = y || 0.0; this.v = { x: random(-1, 1), y: random(-1, 1), mag: 0 }; this.unitV = { x: 0, y: 0, }; this.v.mag = calcMagnitude(this.v.x, this.v.y); this.unitV.x = (this.v.x / this.v.mag); this.unitV.y = (this.v.y / this.v.mag); }, wallAvoid: function(ctx) { var wallPad = 10; if (this.x < wallPad) { this.v.x = this.speed; } else if (this.x > ctx.width - wallPad) { this.v.x = -this.speed; } if (this.y < wallPad) { this.v.y = this.speed; } else if (this.y > ctx.height - wallPad) { this.v.y = -this.speed; } }, ai: function(boids, index, ctx) { percievedCenter = { x: 0, y: 0, count: 0 }; percievedVelocity = { x: 0, y: 0, count: 0 }; mousePredator = { x: ((typeof ctx.touches[0] === "undefined") ? 0 : ctx.touches[0].x), y: ((typeof ctx.touches[0] === "undefined") ? 0 : ctx.touches[0].y) }; for (var i = 0; i < boids.length; i++) { if (i != index) { dist = calculateDistance(this, boids[i]); //Find all other boids close to it if (dist < this.eyesight) { //if the same species then flock if (boids[i].type == this.type) { //Alignment percievedCenter.x += boids[i].x; percievedCenter.y += boids[i].y; percievedCenter.count++; //Cohesion percievedVelocity.x += boids[i].v.x; percievedVelocity.y += boids[i].v.y; percievedVelocity.count++; //Separation if (dist < this.personalSpace + this.size + this.health) { this.avoidOrAttract("avoid", boids[i]); } } else { //if other species fight or flight if (dist < this.size + this.health + boids[i].size + boids[i].health) { this.eat(boids[i]); } else { this.handleOther(boids[i]); } } } //if close enough } //dont check itself } //Loop through boids //Get the average for all near boids if (percievedCenter.count > 0) { percievedCenter.x = ((percievedCenter.x / percievedCenter.count) - this.x) / this.flockDistance; percievedCenter.y = ((percievedCenter.y / percievedCenter.count) - this.y) / this.flockDistance; this.v = calcVectorAdd(this.v, percievedCenter); } if (percievedVelocity.count > 0) { percievedVelocity.x = ((percievedVelocity.x / percievedVelocity.count) - this.v.x) / this.matchVelFactor; percievedVelocity.y = ((percievedVelocity.y / percievedVelocity.count) - this.v.y) / this.matchVelFactor; this.v = calcVectorAdd(this.v, percievedVelocity); } //Avoid Mouse if (calculateDistance(mousePredator, this) < this.eyesight) { var mouseModifier = 20; this.avoidOrAttract("avoid", mousePredator, mouseModifier); } this.wallAvoid(ctx); this.limitVelocity(); }, setUnitVector: function() { var magnitude = calcMagnitude(this.v.x, this.v.y); this.v.x = this.v.x / magnitude; this.v.y = this.v.y / magnitude; }, limitVelocity: function() { this.v.mag = calcMagnitude(this.v.x, this.v.y); this.unitV.x = (this.v.x / this.v.mag); this.unitV.y = (this.v.y / this.v.mag); if (this.v.mag > this.speed) { this.v.x = this.unitV.x * this.speed; this.v.y = this.unitV.y * this.speed; } }, avoidOrAttract: function(action, other, modifier) { var newVector = { x: 0, y: 0 }; var direction = ((action === "avoid") ? -1 : 1); var vModifier = modifier || 1; newVector.x += ((other.x - this.x) * vModifier) * direction; newVector.y += ((other.y - this.y) * vModifier) * direction; this.v = calcVectorAdd(this.v, newVector); }, move: function() { this.x += this.v.x; this.y += this.v.y; if (this.v.mag > this.speed) { this.hunger += this.speed; } else { this.hunger += this.v.mag; } }, eat: function(other) { if (!this.isFull) { if (other.type === "plant") { other.health--; this.health++; this.isFull = true; this.hunger = 0; } } }, handleOther: function(other) { if (other.type === "predator") { this.avoidOrAttract("avoid", other); } }, metabolism: function() { if (this.hunger >= this.hungerLimit) { this.health--; this.hunger = 0; } if (this.hunger >= this.digestTime) { this.isFull = false; } if (this.health <= 0) { this.alive = false; } }, mitosis: function(boids) { if (this.health >= this.maturity) { //reset old boid this.health = 1; birthedBoid = new Boid( this.x + random(-this.personalSpace, this.personalSpace), this.y + random(-this.personalSpace, this.personalSpace) ); birthedBoid.color = this.color; boids.push(birthedBoid); } }, draw: function(ctx) { drawSize = this.size + this.health; ctx.beginPath(); ctx.moveTo(this.x + (this.unitV.x * drawSize), this.y + (this.unitV.y * drawSize)); ctx.lineTo(this.x + (this.unitV.y * drawSize), this.y - (this.unitV.x * drawSize)); ctx.lineTo(this.x - (this.unitV.x * drawSize * 2), this.y - (this.unitV.y * drawSize * 2)); ctx.lineTo(this.x - (this.unitV.y * drawSize), this.y + (this.unitV.x * drawSize)); ctx.lineTo(this.x + (this.unitV.x * drawSize), this.y + (this.unitV.y * drawSize)); ctx.fillStyle = this.color; ctx.shadowBlur = 20; ctx.shadowColor = this.color; ctx.fill(); } }; Predator.prototype = new Boid(); Predator.prototype.constructor = Predator; Predator.constructor = Boid.prototype.constructor; function Predator(x, y) { this.init(x, y); this.type = "predator"; //body this.maturity = 6; this.speed = 6; this.hungerLimit = 25000; this.color = 'rgb(' + ~~random(100, 250) + ',' + ~~random(10, 30) + ',' + ~~random(10, 30) + ')'; //brains this.eyesight = 150; this.flockDistance = 300; } Predator.prototype.eat = function(other) { if (!this.isFull) { if (other.type === "boid") { other.health--; this.health++; this.isFull = true; this.hunger = 0; } } }; Predator.prototype.handleOther = function(other) { if (other.type === "boid") { if (!this.isFull) { this.avoidOrAttract("attract", other); } } }; Predator.prototype.mitosis = function(boids) { if (this.health >= this.maturity) { //reset old boid this.health = 1; birthedBoid = new Predator( this.x + random(-this.personalSpace, this.personalSpace), this.y + random(-this.personalSpace, this.personalSpace) ); birthedBoid.color = this.color; boids.push(birthedBoid); } }; Plant.prototype = new Boid(); Plant.prototype.constructor = Plant; Plant.constructor = Boid.prototype.constructor; function Plant(x, y) { this.init(x, y); this.type = "plant"; //body this.speed = 0; this.size = 10; this.health = ~~random(1, 10); this.color = 'rgb(' + ~~random(130, 210) + ',' + ~~random(40, 140) + ',' + ~~random(160, 220) + ')'; //brains this.eyesight = 0; this.flockDistance = 0; this.eyesight = 0; //range for object dectection this.personalSpace = 100; //distance to avoid safe objects this.flightDistance = 0; //distance to avoid scary objects this.flockDistance = 0; //factor that determines how attracted the boid is to the center of the flock this.matchVelFactor = 0; //factor that determines how much the flock velocity affects the boid } Plant.prototype.ai = function(boids, index, ctx) {}; Plant.prototype.move = function() {}; Plant.prototype.mitosis = function(boids) { var growProbability = 1, maxPlants = 40, plantCount = 0; for (m = boids.length - 1; m >= 0; m--) { if (boids[m].type === "plant") { plantCount++; } } if (plantCount <= maxPlants) { if (random(0, 100) <= growProbability) { birthedBoid = new Plant( this.x + random(-this.personalSpace, this.personalSpace), this.y + random(-this.personalSpace, this.personalSpace) ); birthedBoid.color = this.color; boids.push(birthedBoid); } } }; Plant.prototype.draw = function(ctx) { var drawSize = this.size + this.health; ctx.fillStyle = this.color; ctx.shadowBlur = 40; ctx.shadowColor = this.color; ctx.fillRect(this.x - drawSize, this.y + drawSize, drawSize, drawSize); }; /*********************** SIM ***********************/ var boids = []; var sim = Sketch.create({ container: document.getElementById('container') }); sim.setup = function() { for (i = 0; i < 50; i++) { x = random(0, sim.width); y = random(0, sim.height); sim.spawn(x, y); } }; sim.spawn = function(x, y) { var predatorProbability = 0.1, plantProbability = 0.3; switch (getRandomItem(['boid', 'predator', 'plant'], [1 - predatorProbability - plantProbability, predatorProbability, plantProbability])) { case 'predator': boid = new Predator(x, y); break; case 'plant': boid = new Plant(x, y); break; default: boid = new Boid(x, y); break; } boids.push(boid); }; sim.update = function() { for (i = boids.length - 1; i >= 0; i--) { if (boids[i].alive) { boids[i].ai(boids, i, sim); boids[i].move(); boids[i].metabolism(); boids[i].mitosis(boids); } else { //remove dead boid boids.splice(i, 1); } } }; sim.draw = function() { sim.globalCompositeOperation = 'lighter'; for (i = boids.length - 1; i >= 0; i--) { boids[i].draw(sim); } sim.fillText(boids.length, 20, 20); }; </script> </body> </html>