var nDots = 7; if (document.all&&window.print) document.body.style.cssText="overflow-x:hidden;overflow-y:scroll" var Xpos = 0; var Ypos = 0;
// Фиксируется временной промежуток var DELTAT = .01; // Размеры var SEGLEN = 10; var SPRINGK = 10; // Фиксируются физические константы
var MASS = 1; var GRAVITY = 50; var RESISTANCE = 10; // Условия останова
var STOPVEL = 0.1; var STOPACC = 0.1; var DOTSIZE = 11; // Дополнительные условия
var BOUNCE = 0.75;
var isNetscape = navigator.appName=="Netscape";
var followmouse = true;
var dots = new Array(); init();
function init() { var i = 0; for (i = 0; i < nDots; i++) { dots[i] = new dot(i); }
if (!isNetscape) { // I only know how to read the locations of the // items in IE //skip this for now // setInitPositions(dots) }
// set their positions for (i = 0; i < nDots; i++) { dots[i].obj.left = dots[i].X; dots[i].obj.top = dots[i].Y; }
if (isNetscape) { // start right away since they are positioned // at 0, 0 startanimate(); } else { // let dots sit there for a few seconds // since they're hiding on the real bullets setTimeout("startanimate()", 2000); } }
function startanimate() { setInterval("animate()", 20); }
// This is to line up the bullets with actual LI tags on the page // Had to add -DOTSIZE to X and 2*DOTSIZE to Y for IE 5, not sure why // Still doesn't work great function setInitPositions(dots) { // initialize dot positions to be on top // of the bullets in the <ul>var startloc = document.all.tags("LI"); var i = 0; for (i = 0; i < startloc.length && i < (nDots - 1); i++) { dots[i+1].X = startloc[i].offsetLeft startloc[i].offsetParent.offsetLeft - DOTSIZE; dots[i+1].Y = startloc[i].offsetTop + startloc[i].offsetParent.offsetTop + 2*DOTSIZE; } // put 0th dot above 1st (it is hidden) dots[0].X = dots[1].X; dots[0].Y = dots[1].Y - SEGLEN; }
// just save mouse position for animate() to use function MoveHandler(e) { Xpos = e.pageX; Ypos = e.pageY; return true; }
// just save mouse position for animate() to use function MoveHandlerIE() { Xpos = window.event.x + document.body.scrollLeft; Ypos = window.event.y + document.body.scrollTop; }
// adds force in X and Y to spring for dot[i] on dot[j] function springForce(i, j, spring) { var dx = (dots[i].X - dots[j].X); var dy = (dots[i].Y - dots[j].Y); var len = Math.sqrt(dx*dx + dy*dy); if (len > SEGLEN) { var springF = SPRINGK * (len - SEGLEN); spring.X += (dx / len) * springF; spring.Y += (dy / len) * springF; } }
function animate() { // dots[0] follows the mouse, // though no dot is drawn there var start = 0; if (followmouse) { dots[0].X = Xpos; dots[0].Y = Ypos; start = 1; }
for (i = start ; i < nDots; i++ ) {
var spring = new vec(0, 0); if (i > 0) { springForce(i-1, i, spring); } if (i < (nDots - 1)) { springForce(i+1, i, spring); }
// air resisitance/friction var resist = new vec(-dots[i].dx * RESISTANCE, -dots[i].dy * RESISTANCE);
// compute new accel, including gravity var accel = new vec((spring.X + resist.X)/ MASS, (spring.Y + resist.Y)/ MASS + GRAVITY);
