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小编给大家分享一下JS怎么实现基于Sketch.js模拟成群游动的蝌蚪运动动画效果，相信大部分人都还不怎么了解，因此分享这篇文章给大家参考一下，希望大家阅读完这篇文章后大有收获，下面让我们一起去了解一下吧！
1、js属于一种解释性脚本语言；2、在绝大多数浏览器的支持下，js可以在多种平台下运行，拥有着跨平台特性；3、js属于一种弱类型脚本语言，对使用的数据类型未做出严格的要求，能够进行类型转换，简单又容易上手；4、js语言安全性高，只能通过浏览器实现信息浏览或动态交互，从而有效地防止数据的丢失；5、基于对象的脚本语言，js不仅可以创建对象，也能使用现有的对象。
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 class=" -webkit- js flexbox canvas canvastext webgl no-touch geolocation postmessage websqldatabase indexeddb hashchange history draganddrop websockets rgba hsla multiplebgs backgroundsize borderimage borderradius boxshadow textshadow opacity cssanimations csscolumns cssgradients cssreflections csstransforms csstransforms3d csstransitions fontface generatedcontent video audio localstorage sessionstorage webworkers applicationcache svg inlinesvg smil svgclippaths">
<head>
<meta charset="UTF-8">
<title>HTML5 Preview Panel</title>
<script src="prefixfree.min.js"></script>
<script src="modernizr.js"></script>
<style>
body {
background-color: #222;
}
</style>
</head>
<body>
<script src="sketch.min.js"></script>
<div id="container">
<canvas class="sketch" id="sketch-0" height="208" width="607"></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>以上是“JS怎么实现基于Sketch.js模拟成群游动的蝌蚪运动动画效果”这篇文章的所有内容，感谢各位的阅读！相信大家都有了一定的了解，希望分享的内容对大家有所帮助，如果还想学习更多知识，欢迎关注亿速云行业资讯频道！
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