javascript - Canvas 粒子、碰撞和性能

Question

我正在创建一个网络应用程序，该应用程序具有交互式背景，粒子会四处弹跳。在任何时候，屏幕上都有大约 200 个圆形粒子，最多大约 800 个粒子。为粒子运行的一些碰撞和效果是以下原型(prototype)。我想知道是否可以通过使用 Web Worker 进行这些计算来提高性能？

/**
*   Particles
*/

Jarvis.prototype.genForegroundParticles = function(options, count){

    count = count || this.logoParticlesNum;

    for (var i = 0; i < count; i++) {
        this.logoParticles.push(new Particle());
    }

}

Jarvis.prototype.genBackgroundParticles = function(options, count){

    count = count || this.backgroundParticlesNum;

    for (var i = 0; i < count; i++) {
        this.backgroundParticles.push(new Particle(options));
    }

}

Jarvis.prototype.motion = {
    linear : function(particle, pIndex, particles){
        particle.x += particle.vx
        particle.y += particle.vy
    },
    normalizeVelocity : function(particle, pIndex, particles){

        if (particle.vx - particle.vxInitial > 1) {
            particle.vx -= 0.05;
        } else if (particle.vx - particle.vxInitial < -1) {
            particle.vx += 0.05;
        }

        if (particle.vy - particle.vyInitial > 1) {
            particle.vy -= 0.05;
        } else if (particle.vx - particle.vxInitial < -1) {
            particle.vy += 0.05;
        }

    },
    explode : function(particle, pIndex, particles) {

        if (particle.isBottomOut()) {
            particles.splice(pIndex, 1);
        } else {
            particle.x += particle.vx;
            particle.y += particle.vy;
            particle.vy += 0.1;
        }

        if (particles.length === 0){
            particles.motion.removeMotion("explode");
            this.allowMenu = true;
        }       

    }
}

Jarvis.prototype.collision = {
    boundingBox: function(particle, pIndex, particles){

        if (particle.y > (this.HEIGHT - particle.radius) || particle.y < particle.radius) {
            particle.vy *= -1;
        }

        if(particle.x > (this.WIDTH - particle.radius) || particle.x < particle.radius) {
            particle.vx *= -1;
        }
    },
    boundingBoxGravity: function(particle, pIndex, particles){
        // TODO: FIX GRAVITY TO WORK PROPERLY IN COMBINATION WITH FX AND MOTION
        if (particle.y > (this.HEIGHT - particle.radius) || particle.y < particle.radius) {
            particle.vy *= -1;
            particle.vy += 5;
        } 

        if(particle.x > (this.WIDTH - particle.radius) || particle.x < particle.radius) {
            particle.vx *= -1;
            particle.vx += 5;
        }

    },
    infinity: function(particle, pIndex, particles){

        if (particle.x > this.WIDTH){
            particle.x = 0;
        }

        if (particle.x < 0){
            particle.x = this.WIDTH;
        }

        if (particle.y > this.HEIGHT){
            particle.y = 0;
        }       

        if (particle.y < 0) {
            particle.y = this.HEIGHT;
        }

    }
}

Jarvis.prototype.fx = {
    link : function(particle, pIndex, particles){

        for(var j = pIndex + 1; j < particles.length; j++) {

            var p1 = particle;
            var p2 = particles[j];
            var particleDistance = getDistance(p1, p2);

            if (particleDistance <= this.particleMinLinkDistance) {
                this.backgroundCtx.beginPath();
                this.backgroundCtx.strokeStyle = "rgba("+p1.red+", "+p1.green+", "+p1.blue+","+ (p1.opacity - particleDistance / this.particleMinLinkDistance) +")";
                this.backgroundCtx.moveTo(p1.x, p1.y);
                this.backgroundCtx.lineTo(p2.x, p2.y);
                this.backgroundCtx.stroke();
                this.backgroundCtx.closePath();
            }
        }
    },
    shake : function(particle, pIndex, particles){

        if (particle.xInitial - particle.x >= this.shakeAreaThreshold){
            particle.xOper = (randBtwn(this.shakeFactorMin, this.shakeFactorMax) * 2) % (this.WIDTH);
        } else if (particle.xInitial - particle.x <= -this.shakeAreaThreshold) {
            particle.xOper = (randBtwn(-this.shakeFactorMax, this.shakeFactorMin) * 2) % (this.WIDTH);
        }

        if (particle.yInitial - particle.y >= this.shakeAreaThreshold){
            particle.yOper = (randBtwn(this.shakeFactorMin, this.shakeFactorMax) * 2) % (this.HEIGHT);
        } else if (particle.yInitial - particle.y <= -this.shakeAreaThreshold) {
            particle.yOper = (randBtwn(-this.shakeFactorMax, this.shakeFactorMin) * 2) % (this.HEIGHT);
        }       

        particle.x += particle.xOper;
        particle.y += particle.yOper;

    },
    radialWave : function(particle, pIndex, particles){

        var distance = getDistance(particle, this.center);

        if (particle.radius >= (this.dim * 0.0085)) {
            particle.radiusOper = -0.02;
        } else if (particle.radius <= 1) {
            particle.radiusOper = 0.02;
        }

        particle.radius += particle.radiusOper * particle.radius;
    },
    responsive : function(particle, pIndex, particles){

        var newPosX = (this.logoParticles.logoOffsetX + this.logoParticles.particleRadius) + (this.logoParticles.particleDistance + this.logoParticles.particleRadius) * particle.arrPos.x;
        var newPosY = (this.logoParticles.logoOffsetY + this.logoParticles.particleRadius) + (this.logoParticles.particleDistance + this.logoParticles.particleRadius) * particle.arrPos.y;

        if (particle.xInitial !== newPosX || particle.yInitial !== newPosY){

            particle.xInitial = newPosX;
            particle.yInitial = newPosY;
            particle.x = particle.xInitial;
            particle.y = particle.yInitial;

        }

    },
    motionDetect : function(particle, pIndex, particles){

        var isClose = false;
        var distance = null;

        for (var i = 0; i < this.touches.length; i++) {

            var t = this.touches[i];

            var point = {
                x : t.clientX,
                y : t.clientY
            }

            var d = getDistance(point, particle); 

            if (d <= this.blackhole) {
                isClose = true;

                if (d <= distance || distance === null) {
                    distance = d;
                }

            }  

        }

        if (isClose){
            if (particle.radius < (this.dim * 0.0085)) {
                particle.radius += 0.25;
            }
            if (particle.green >= 0 && particle.blue >= 0) {
                particle.green -= 10;
                particle.blue -= 10;
            }           
        } else {
            if (particle.radius > particle.initialRadius) {
                particle.radius -= 0.25;
            }
            if (particle.green <= 255 && particle.blue <= 255) {
                particle.green += 10;
                particle.blue += 10;
            }           
        }

    },
    reverseBlackhole : function(particle, pIndex, particles){

        for (var i = 0; i < this.touches.length; i++) {

            var t = this.touches[i];

            var point = {
                x : t.clientX,
                y : t.clientY
            } 

            var distance = getDistance(point, particle);

            if (distance <= this.blackhole){

                var diff = getPointsDifference(point, particle);

                particle.vx += -diff.x / distance;
                particle.vy += -diff.y / distance;
            }

        }
    }
}

此外，如果有人想知道我有 3 个 Canvas 层，我会添加粒子渲染功能以及所有 Canvas 层的清除功能

1. 绘制全屏径向渐变和粒子的背景

2. 菜单 Canvas

3. 菜单按钮覆盖选择器(显示哪个菜单处于事件状态等)

---

Jarvis.prototype.backgroundDraw = function() {

    // particles

    var that = this;

    this.logoParticles.forEach(function(particle, i){

        particle.draw(that.backgroundCtx);

        that.logoParticles.motion.forEach(function(motionType, motionIndex){
            that.motion[motionType].call(that, particle, i, that.logoParticles, "foregroundParticles");
        });
        that.logoParticles.fx.forEach(function(fxType, fxIndex){
            that.fx[fxType].call(that, particle, i, that.logoParticles, "foregroundParticles");
        });
        that.logoParticles.collision.forEach(function(collisionType, collisionIndex){
            that.collision[collisionType].call(that, particle, i, that.logoParticles, "foregroundParticles");
        });
    });

    this.backgroundParticles.forEach(function(particle, i){

        particle.draw(that.backgroundCtx);

        that.backgroundParticles.motion.forEach(function(motionType, motionIndex){
            that.motion[motionType].call(that, particle, i, that.backgroundParticles, "backgroundParticles");
        });
        that.backgroundParticles.fx.forEach(function(fxType, fxIndex){
            that.fx[fxType].call(that, particle, i, that.backgroundParticles, "backgroundParticles");
        });
        that.backgroundParticles.collision.forEach(function(collisionType, collisionIndex){
            that.collision[collisionType].call(that, particle, i, that.backgroundParticles, "backgroundParticles");
        });
    });

}

Jarvis.prototype.clearCanvas = function() {

    switch(this.background.type){
        case "radial_gradient":
            this.setBackgroundRadialGradient(this.background.color1, this.background.color2);
            break;
        case "plane_color":
            this.setBackgroundColor(this.background.red, this.background.green, this.background.blue, this.background.opacity);
            break;
        default:
            this.setBackgroundColor(142, 214, 255, 1);
    }

    this.foregroundCtx.clearRect(this.clearStartX, this.clearStartY, this.clearDistance, this.clearDistance);
    this.middlegroundCtx.clearRect(this.clearStartX, this.clearStartY, this.clearDistance, this.clearDistance);
}

Jarvis.prototype.mainLoop = function() {
    this.clearCanvas();
    this.backgroundDraw();
    this.drawMenu();
    window.requestAnimFrame(this.mainLoop.bind(this));
}

任何其他优化技巧将不胜感激。我已经阅读了几篇文章，但不确定如何进一步优化此代码。

Answer 1

您可以使用 FabricJS Canvas 图书馆。 FabricJS 默认支持交互性，当您创建一个新对象(圆形、矩形等)时，您可以通过鼠标或触摸屏对其进行操作。

var canvas = new fabric.Canvas('c');
var rect = new fabric.Rect({
    width: 10, height: 20,
    left: 100, top: 100,
    fill: 'yellow',
    angle: 30
});

canvas.add(rect); 

看，我们以面向对象的方式在那里工作。