让它下雪插件中的多个随机图像

Question

我一直在玩 jason brown 的 let it snow 插件。他的代码仅适用于单个自定义图像，我一直在试图弄清楚如何更改代码以使其在随机范围内适应多个自定义图像。

!function($){  
var defaults = {
speed: 0,
interaction: true,
size: 2,
count: 200,
opacity: 0,
color: "#ffffff",
windPower: 0,
image: false
};
  $.fn.let_it_snow = function(options){
var settings = $.extend({}, defaults, options),
    el = $(this),
    flakes = [],
    canvas = el.get(0),
    ctx = canvas.getContext("2d"),
    flakeCount = settings.count,
    mX = -100,
    mY = -100;
    canvas.width = window.innerWidth;
    canvas.height = window.innerHeight;

(function() {
    var requestAnimationFrame = window.requestAnimationFrame || window.mozRequestAnimationFrame || window.webkitRequestAnimationFrame || window.msRequestAnimationFrame ||
    function(callback) {
        window.setTimeout(callback, 1000 / 60);
    };
    window.requestAnimationFrame = requestAnimationFrame;
})();

function snow() {
    ctx.clearRect(0, 0, canvas.width, canvas.height);

    for (var i = 0; i < flakeCount; i++) {
        var flake = flakes[i],
            x = mX,
            y = mY,
            minDist = 100,
            x2 = flake.x,
            y2 = flake.y;

        var dist = Math.sqrt((x2 - x) * (x2 - x) + (y2 - y) * (y2 - y)),
            dx = x2 - x,
            dy = y2 - y;

        if (dist < minDist) {
            var force = minDist / (dist * dist),
                xcomp = (x - x2) / dist,
                ycomp = (y - y2) / dist,
                deltaV = force / 2;

            flake.velX -= deltaV * xcomp;
            flake.velY -= deltaV * ycomp;

        } else {
            flake.velX *= .98;
            if (flake.velY <= flake.speed) {
                flake.velY = flake.speed
            }

            switch (settings.windPower) { 
              case false:
                flake.velX += Math.cos(flake.step += .05) * flake.stepSize;
              break;

              case 0:
                flake.velX += Math.cos(flake.step += .05) * flake.stepSize;
              break;

              default: 
                flake.velX += 0.01 + (settings.windPower/100);
            }
        }

        var s = settings.color;
        var patt = /^#([\da-fA-F]{2})([\da-fA-F]{2})([\da-fA-F]{2})$/;
        var matches = patt.exec(s);
        var rgb = parseInt(matches[1], 16)+","+parseInt(matches[2], 16)+","+parseInt(matches[3], 16);


        flake.y += flake.velY;
        flake.x += flake.velX;

        if (flake.y >= canvas.height || flake.y <= 0) {
            reset(flake);
        }


        if (flake.x >= canvas.width || flake.x <= 0) {
            reset(flake);
        }
        if (settings.image == false) {
          ctx.fillStyle = "rgba(" + rgb + "," + flake.opacity + ")"
          ctx.beginPath();
          ctx.arc(flake.x, flake.y, flake.size, 0, Math.PI * 2);
          ctx.fill();
        } else {

          ctx.drawImage($("img#lis_flake").get(0), flake.x, flake.y, flake.size * 2, flake.size * 2);
        }

    }
    requestAnimationFrame(snow);
};


function reset(flake) {

    if (settings.windPower == false || settings.windPower == 0) {
      flake.x = Math.floor(Math.random() * canvas.width);
      flake.y = 0;
    } else {
      if (settings.windPower > 0) {
        var xarray = Array(Math.floor(Math.random() * canvas.width), 0);
        var yarray = Array(0, Math.floor(Math.random() * canvas.height))
        var allarray = Array(xarray, yarray)

        var selected_array = allarray[Math.floor(Math.random()*allarray.length)];

         flake.x = selected_array[0];
         flake.y = selected_array[1];
      } else {
        var xarray = Array(Math.floor(Math.random() * canvas.width),0);
        var yarray = Array(canvas.width, Math.floor(Math.random() * canvas.height))
        var allarray = Array(xarray, yarray)

        var selected_array = allarray[Math.floor(Math.random()*allarray.length)];

         flake.x = selected_array[0];
         flake.y = selected_array[1];
      }
    }

    flake.size = (Math.random() * 3) + settings.size;
    flake.speed = (Math.random() * 1) + settings.speed;
    flake.velY = flake.speed;
    flake.velX = 0;
    flake.opacity = (Math.random() * 0.5) + settings.opacity;
}
 function init() {
  for (var i = 0; i < flakeCount; i++) {
      var x = Math.floor(Math.random() * canvas.width),
          y = Math.floor(Math.random() * canvas.height),
          size = (Math.random() * 3)  + settings.size,
          speed = (Math.random() * 1) + settings.speed,
          opacity = (Math.random() * 0.5) + settings.opacity;

      flakes.push({
          speed: speed,
          velY: speed,
          velX: 0,
          x: x,
          y: y,
          size: size,
          stepSize: (Math.random()) / 30,
          step: 0,
          angle: 180,
          opacity: opacity
      });
  }

  snow();
}

if (settings.image != false) {
  $("<img src='"+settings.image+"' style='display: none' id='lis_flake'>").prependTo("body")
}

init();

$(window).resize(function() {
  if(this.resizeTO) clearTimeout(this.resizeTO);
  this.resizeTO = setTimeout(function() {
    el2 = el.clone();
    el2.insertAfter(el);
    el.remove();

    el2.let_it_snow(settings);
  }, 200);
});

if (settings.interaction == true) {
  canvas.addEventListener("mousemove", function(e) {
      mX = e.clientX,
      mY = e.clientY
  });
}}}(window.jQuery);

在代码顶部的默认属性中，就是您指向图像 url 的位置。下面是我输入的内容，所以它在 image1.jpeg 和 image2.jpeg

之间进行选择

image: "img/image'+Math.floor((Math.random() * 2) + 1)+'.jpeg";

然而，当 "snowflakes" 重生时，图像保持不变，而不是再次选择随机数。我必须更改什么才能在创建雪花时选择随机图像并变成它？

我希望我的问题很清楚，如果您需要更清楚的信息，请告诉我。我是 j-script 的新手，如有任何帮助，我们将不胜感激。

Answer 1

插件作者使用

将单个自定义图像加载到隐藏元素中

if (settings.image != false) {
  $("<img src='"+settings.image+"' style='display: none' id='lis_flake'>").prependTo("body")
}

并用这个加载雪花

ctx.drawImage($("img#lis_flake").get(0)

此解决方案尚未经过测试，但如果您愿意对插件进行一些修改，则可以进行以下更改以使用两个可选图像：

1) 在 init(); 函数调用之前添加它。它添加了另一个来自 settings.image2.

的隐藏图像

if (settings.image2) {
  $("<img src='"+settings.image2+"' style='display: none' id='lis_flake2'>").prependTo("body")
}

2) 将function init()修改为

flakes.push({
    // Create a new property called 'imgNum' to hold either "" or "2";
    imgNum: (settings.image2 && Math.floor(Math.random() * 2) === 0 ? "2" : ""),

    // rest of the code ...
    speed: speed,

3) 改变

ctx.drawImage($("img#lis_flake").get(0), flake.x, flake.y, flake.size * 2, flake.size * 2);

到

ctx.drawImage($("img#lis_flake" + flake.imgNum).get(0), flake.x, flake.y, flake.size * 2, flake.size * 2);

根据init()中随机设置的flake.imgNum选择图片。

4) 像这样更改传递给插件的选项：

options = {
    // other options
    image:  "img/image1.jpeg",
    image2: "img/image2.jpeg",
    // other options
}

如果未设置 image2，这些更改应该允许插件仍然工作。

让它下雪插件中的多个随机图像

multiple random images in let it snow plug-in

javascript

random

image