JS實現基于Sketch.js模擬成群游動的蝌蚪運動動畫效果【附demo源碼下載】
更新時間：2017年08月18日 11:57:30 作者：陳小峰_iefreer
這篇文章主要介紹了JS實現基于Sketch.js模擬成群游動的蝌蚪運動動畫效果,涉及Sketch.js插件的使用及HTML5元素的應用技巧,并附帶demo源碼供讀者下載參考,需要的朋友可以參考下
本文實例講述了JS實現基于Sketch.js模擬成群游動的蝌蚪運動動畫效果。分享給大家供大家參考，具體如下：
基于Sketch.js，實現了物體觸碰檢測（蝌蚪會遇到障礙物以及聰明的躲避鼠標的點擊），隨機運動，聚集算法等。
已經具備了游戲的基本要素，擴展一下可以變成一個不錯的 HTML5 游戲。
演示效果如下：
完整代碼如下：
<!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>
附：完整實例代碼點擊此處本站下載。
更多關于JavaScript相關內容感興趣的讀者可查看本站專題：《JavaScript動畫特效與技巧匯總》、《JavaScript圖形繪制技巧總結》、《JavaScript切換特效與技巧總結》、《JavaScript錯誤與調試技巧總結》、《JavaScript數據結構與算法技巧總結》及《JavaScript數學運算用法總結》
希望本文所述對大家JavaScript程序設計有所幫助。
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