调整视差效果？

Question

我看了一眼，并询问周围的问题解决方案，到目前为止没有运气。我希望有人可以帮助我。

我一直在研究基于[this] [1]教程的视差效果，我发现了一段时间。它做了应有的事情，因为所有元素都会左右移动，具体取决于移动鼠标的位置。我想调整它，如果可能的话，它可以根据鼠标的位置向左或向右平滑滚动。就像现在一样，它只在鼠标移动时移动。我宁愿更改它，以便它以设定的速度连续滚动给定的左右空间宽度，具体取决于鼠标相对于中心的位置。

这是我到目前为止的代码，它的工作方式与上面链接的教程的第一部分相似：

var headerDiv = document.getElementById("header");

var image1Div = document.getElementById("image1");
var image2Div = document.getElementById("image2");
var image3Div = document.getElementById("image3");
var image4Div = document.getElementById("image4");

var headerDivHeight;
var canStartParallax = false;
var canPositionDivsVertically = true;

// Detect if the browser is IE or not.
// If it is not IE, we assume that the browser is NS.
var IE = document.all?true:false

// If NS -- that is, !IE -- then set up for mouse capture
if (!IE) document.captureEvents(Event.MOUSEMOVE)

// Set-up to use getMouseXY function onMouseMove
document.onmousemove = getMouseXY;

// Temporary variables to hold mouse x-y pos.s
var tempX = 0;
var tempY = 0;

var objectArray = new Array();

window.onload = function()
{
    showAllOfTheContent();

    headerDivHeight = headerDiv.offsetHeight;

    fillObjectArray();
    setimage1ToTransparent();
    positionDivs();

    turnOffPreloaderDotAnimation();
    objectAnimation();
}

function showAllOfTheContent()
{
    document.getElementById("content").setAttribute("class", "");
}

function fillObjectArray()
{
    var image1X = { getX: function() {return 0.5 * windowWidth + 50} };
    var image1Y = 10;
    var image1Factor = 0.0;
    var image1Array = new Array();
    image1Array.push(image1Div, image1X, image1Y, image1Factor);
    objectArray.push(image1Array);

    var image2X = { getX: function() {return 0.5 * windowWidth - 202} }; //position div from half width of the page
    var image2Y = 0;
    var image2Factor = 0.20; //parallax shift factor, the bigger the value, the more it shift for parallax movement
    var image2Array = new Array();
    image2Array.push(image2Div, image2X, image2Y, image2Factor);
    objectArray.push(image2Array);

    var image3X = { getX: function() {return 0.5 * windowWidth - -160} };
    var image3Y = 23;
    var image3Factor = 0.60;
    var image3Array = new Array();
    image3Array.push(image3Div, image3X, image3Y, image3Factor);
    objectArray.push(image3Array);

    var image4X = { getX: function() {return 0.5 * windowWidth + 50} };
    var image4Y = 60;
    var image4Factor = 1.0;
    var image4Array = new Array();
    image4Array.push(image4Div, image4X, image4Y, image4Factor);
    objectArray.push(image4Array);

    var image5Div = document.getElementById("image5");
    var image5X = { getX: function() {return 0.5 * windowWidth + 500} };
    var image5Y = 400;
    var image5Factor = 0.85;
    var image5Array = new Array();
    image5Array.push(image5Div, image5X, image5Y, image5Factor);
    objectArray.push(image5Array);
}

// Main function to retrieve mouse x-y pos.s

function getMouseXY(e)
{
      if (IE) { // grab the x-y pos.s if browser is IE
        tempX = event.clientX + document.body.scrollLeft
        tempY = event.clientY + document.body.scrollTop
      } else {  // grab the x-y pos.s if browser is NS
        tempX = e.pageX
        tempY = e.pageY
      }  
      // catch possible negative values in NS4
      if (tempX < 0){tempX = 0}
      if (tempY < 0){tempY = 0}  

      moveDiv(tempX, tempY);

      return true
}

function moveDiv(tempXsent, tempYsent)
{
    if (canStartParallax == true)
    {
        var tempXreceived = tempXsent;
        var tempYreceived = tempYsent;

        if (tempYreceived <= headerDivHeight) //limit the mouse over area
        {
            for (var i=0;i<objectArray.length;i++)
            {
                var yourDivPositionX = objectArray[i][3] * (0.5 * windowWidth - tempXreceived) + objectArray[i][1].getX();
                objectArray[i][0].style.left = yourDivPositionX + 'px';
            }
        }
    }
}

function positionDivs()
{
    var verticalParallaxFactorMultiplyNumber = 2; //the bigger this number, the vertical gap between header object animation will be bigger too

    for (var i=0;i<objectArray.length;i++)
    {
        objectArray[i][0].style.left = objectArray[i][1].getX() + "px";

        if (canPositionDivsVertically == true)
        {
            if ((objectArray[i][0] == image2Div) || (objectArray[i][0] == image3Div) || (objectArray[i][0] == image4Div))
            {
                objectArray[i][0].style.top = objectArray[i][2] - ((1 + (verticalParallaxFactorMultiplyNumber * objectArray[i][3])) * windowHeight) + "px";
            }
            else if ((objectArray[i][0] == image1Div))
            {
                objectArray[i][0].style.top = objectArray[i][2] + "px";
            }
            else
            {
                objectArray[i][0].style.top = objectArray[i][2] + ((1 + (verticalParallaxFactorMultiplyNumber * objectArray[i][3])) * windowHeight) + "px";
            }
        }
    }
}

function setimage1ToTransparent()
{
    image1Div.style.opacity = 0;
    image1Div.style.filter = "alpha(opacity=" + 0 + ")";
}

function objectAnimation()
{
    var objectAnimationDuration = 2000;

    //animate preloader
    $(preloaderAndStringContainerDiv).stop().animate({top: (-1 * windowHeight) + "px"}, objectAnimationDuration, function() {hidePreloader()});

    for (var i=0;i<objectArray.length;i++)
    {
        if ((objectArray[i][0] == image1Div))
        {
            $(objectArray[i][0]).stop().fadeTo(objectAnimationDuration, 1);
        }
        else
        {
            if ((navigator.userAgent.match(/iPad/i) != null) || (navigator.userAgent.match(/iPhone/i) != null) || (navigator.userAgent.match(/iPod/i) != null)) //if using safari mobile device, never turn on parallax
            {
                $(objectArray[i][0]).stop().animate({top: objectArray[i][2] + "px"}, objectAnimationDuration, function() {canPositionDivsVertically = false});
            }
            else
            {
                $(objectArray[i][0]).stop().animate({top: objectArray[i][2] + "px"}, objectAnimationDuration, function() {canStartParallax = true; canPositionDivsVertically = false});
            }
        }
    }
}

function resizeHeader()
{
    positionDivs();
}

有人可以告诉我吗？我真的很感激。感谢。

Answer 1

目前，moveDiv例程由mouseXY函数调用，该函数被设置为mousemove事件的处理程序。所以在你移动鼠标之前，没有任何东西在触发。

相反，你想使用mousemove改变一些速度向量，并使用一些触发器进入一个连续循环（我建议以setInterval开头），它使用这个速度向量来调用moveDiv。

由于您不希望在悬停移动时发生这种情况（否则当鼠标悬停在盒子上时它将首先疯狂旋转），请考虑在mousedown上进入循环，并在mouseup和mouseout上退出循环。

在这里做动画时，请看一下使用requestAnimationFrame，这是新浏览器中支持平滑动画渲染的一项功能，您可以为其提供重复执行的功能：

http://paulirish.com/2011/requestanimationframe-for-smart-animating/

使用这些方法中的任何一种，我建议你保持速度的向量（由mousemove事件调整）和每帧更新的时间戳变量。您将无法预测调用代码之间的延迟，因此为了保持一致，您应该使用现在和最后一帧时间戳之间的差值来计算移动的距离。