116 lines
3.8 KiB
JavaScript
116 lines
3.8 KiB
JavaScript
//
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// Copyright (C) 2008 by Fabian Schlieper
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// Schnee v1.2
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// http://www.fabi.me/
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// Ohne dieses Copyright darf dieser Code nicht verwendet werden!
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//
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// die ID des HTML-Elements, in dem es schneien soll
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var snow_area_id = 'winter';
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// maximale Anzahl der sichtbaren Schneeflocken
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var snow_flake_count = 50;
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// die verschiedenen Farbe, die die Schneeflocken haben sollen
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var snow_colors = new Array('#AAAACC','#DDDDFF','#CCCCDD','#F3F3F3','#F0FFFF');
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// die Schriftarten, aus denen die Schneeflocken bestehen sollen
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var snow_fonts = new Array('Arial Black', 'Arial Narrow', 'Times', 'Comic Sans MS');
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var snow_char = '●'; // das Zeichen, das als Schneeflocke verwendet wird
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var snow_gravity = 0.8; // wie schnell die Schneeflocken fallen
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var snow_max_size = 22; // die maximale Schriftgröße einer Schneeflocke
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var snow_min_size = 8; // die minimale Schriftgröße einer Schneeflocke
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var snow_init_delay = 30; // Verzögerungszeit in Millisekunden, bevor es zu schneien anfängt
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// ######################################################################
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// HIER ENDET DIE KONFIGURATION. ÄNDERUNGEN IM FOLGENDEN SETZEN JAVSCRIPT-KENNTNISSE VORAUS
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// ######################################################################
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var snow_init_time = 0;
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var snowflakes = new Array();
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var snow_area_el = null;
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function createSnowflakes()
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{
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var style = 'position:absolute; top:-' + snow_max_size + 'px; z-index:99;';
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for (var i = 0; i <= snow_flake_count; i++)
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document.write('<sp' + 'an id="snwflk' + i + '" style="' + style + '">' + snow_char + '</sp' + 'an>');
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}
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function randInt(range) { return Math.floor(Math.random() * range); }
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function initSnow()
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{
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snow_area_el = document.getElementById(snow_area_id);
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// reapeat until we have the snow_area_el
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if(!snow_area_el || snow_area_el.offsetWidth <= snow_max_size || snow_area_el.offsetHeight <= snow_max_size) {
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// after 5 secs cancel
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if(snow_init_time < 5000)
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window.setTimeout('initSnow()', 50);
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snow_init_time += 50;
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return;
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}
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// offest fix
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snow_area_el.style.position = 'relative';
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for (var i = 0; i <= snow_flake_count; i++)
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{
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snowflakes[i] = document.getElementById('snwflk' + i);
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snowflakes[i].size = (randInt(snow_max_size - snow_min_size) + snow_min_size);
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snowflakes[i].posx = -snowflakes[i].size;
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snowflakes[i].posy = -snowflakes[i].size;
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snowflakes[i].sink = (snow_gravity * snowflakes[i].size / snow_min_size);
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snowflakes[i].wobamp = (Math.random() * (snowflakes[i].size));
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snowflakes[i].wob = 0.0;
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snowflakes[i].wobspeed = (0.03 + Math.random() / 10.0);
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snowflakes[i].style.fontFamily = snow_fonts[randInt(snow_fonts.length)];
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snowflakes[i].style.fontSize = snowflakes[i].size + 'px';
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snowflakes[i].style.color = snow_colors[randInt(snow_colors.length)];
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}
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window.setInterval('updateSnow()', 50);
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}
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function updateSnow()
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{
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var bl = snow_area_el.offsetLeft;
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var bt = snow_area_el.offsetTop;
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var bw = snow_area_el.offsetWidth;
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var bh = snow_area_el.offsetHeight;
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var br = bl + bw;
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var bb = bt + bh;
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for (var i = 0; i <= snow_flake_count; i++)
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{
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snowflakes[i].wob += snowflakes[i].wobspeed;
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var x = snowflakes[i].posx + (snowflakes[i].wobamp * Math.sin(snowflakes[i].wob));
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snowflakes[i].posy += snowflakes[i].sink;
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snowflakes[i].style.left = Math.round(x) + 'px';
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snowflakes[i].style.top = Math.round(snowflakes[i].posy) + 'px';
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var s = snowflakes[i].size;
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// check bounds
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if (snowflakes[i].posy > (bb - s) || x < bl || x > (br - s))
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{
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snowflakes[i].posx = bl + s + randInt(bw - (3 * s));
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if(snowflakes[i].posy < 0)
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snowflakes[i].posy = bt + randInt(bh - 2 * s);
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else
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snowflakes[i].posy = bt;
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}
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}
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}
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// Schnee initialisieren
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createSnowflakes();
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window.setTimeout('initSnow()', Math.max(50, snow_init_delay)); |