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/*
* jquery.collision
* https://github.com/ducksboard/gridster.js
*
* Copyright (c) 2012 ducksboard
* Licensed under the MIT licenses.
*/
;(function($, window, document, undefined){
var defaults = {
colliders_context: document.body
// ,on_overlap: function(collider_data){},
// on_overlap_start : function(collider_data){},
// on_overlap_stop : function(collider_data){}
};
/**
* Detects collisions between a DOM element against other DOM elements or
* Coords objects.
*
* @class Collision
* @uses Coords
* @param {HTMLElement} el The jQuery wrapped HTMLElement.
* @param {HTMLElement|Array} colliders Can be a jQuery collection
* of HTMLElements or an Array of Coords instances.
* @param {Object} [options] An Object with all options you want to
* overwrite:
* @param {Function} [options.on_overlap_start] Executes a function the first
* time each `collider ` is overlapped.
* @param {Function} [options.on_overlap_stop] Executes a function when a
* `collider` is no longer collided.
* @param {Function} [options.on_overlap] Executes a function when the
* mouse is moved during the collision.
* @return {Object} Collision instance.
* @constructor
*/
function Collision(el, colliders, options) {
this.options = $.extend(defaults, options);
this.$element = el;
this.last_colliders = [];
this.last_colliders_coords = [];
if (typeof colliders === 'string' || colliders instanceof jQuery) {
this.$colliders = $(colliders,
this.options.colliders_context).not(this.$element);
}else{
this.colliders = $(colliders);
}
this.init();
}
var fn = Collision.prototype;
fn.init = function() {
this.find_collisions();
};
fn.overlaps = function(a, b) {
var x = false;
var y = false;
if ((b.x1 >= a.x1 && b.x1 <= a.x2) ||
(b.x2 >= a.x1 && b.x2 <= a.x2) ||
(a.x1 >= b.x1 && a.x2 <= b.x2)
) { x = true; }
if ((b.y1 >= a.y1 && b.y1 <= a.y2) ||
(b.y2 >= a.y1 && b.y2 <= a.y2) ||
(a.y1 >= b.y1 && a.y2 <= b.y2)
) { y = true; }
return (x && y);
};
fn.detect_overlapping_region = function(a, b){
var regionX = '';
var regionY = '';
if (a.y1 > b.cy && a.y1 < b.y2) { regionX = 'N'; }
if (a.y2 > b.y1 && a.y2 < b.cy) { regionX = 'S'; }
if (a.x1 > b.cx && a.x1 < b.x2) { regionY = 'W'; }
if (a.x2 > b.x1 && a.x2 < b.cx) { regionY = 'E'; }
return (regionX + regionY) || 'C';
};
fn.calculate_overlapped_area_coords = function(a, b){
var x1 = Math.max(a.x1, b.x1);
var y1 = Math.max(a.y1, b.y1);
var x2 = Math.min(a.x2, b.x2);
var y2 = Math.min(a.y2, b.y2);
return $({
left: x1,
top: y1,
width : (x2 - x1),
height: (y2 - y1)
}).coords().get();
};
fn.calculate_overlapped_area = function(coords){
return (coords.width * coords.height);
};
fn.manage_colliders_start_stop = function(new_colliders_coords, start_callback, stop_callback){
var last = this.last_colliders_coords;
for (var i = 0, il = last.length; i < il; i++) {
if ($.inArray(last[i], new_colliders_coords) === -1) {
start_callback.call(this, last[i]);
}
}
for (var j = 0, jl = new_colliders_coords.length; j < jl; j++) {
if ($.inArray(new_colliders_coords[j], last) === -1) {
stop_callback.call(this, new_colliders_coords[j]);
}
}
};
fn.find_collisions = function(player_data_coords){
var self = this;
var colliders_coords = [];
var colliders_data = [];
var $colliders = (this.colliders || this.$colliders);
var count = $colliders.length;
var player_coords = self.$element.coords()
.update(player_data_coords || false).get();
while(count--){
var $collider = self.$colliders ?
$($colliders[count]) : $colliders[count];
var $collider_coords_ins = ($collider.isCoords) ?
$collider : $collider.coords();
var collider_coords = $collider_coords_ins.get();
var overlaps = self.overlaps(player_coords, collider_coords);
if (!overlaps) {
continue;
}
var region = self.detect_overlapping_region(
player_coords, collider_coords);
//todo: make this an option
if (region === 'C'){
var area_coords = self.calculate_overlapped_area_coords(
player_coords, collider_coords);
var area = self.calculate_overlapped_area(area_coords);
var collider_data = {
area: area,
area_coords : area_coords,
region: region,
coords: collider_coords,
player_coords: player_coords,
el: $collider
};
if (self.options.on_overlap) {
self.options.on_overlap.call(this, collider_data);
}
colliders_coords.push($collider_coords_ins);
colliders_data.push(collider_data);
}
}
if (self.options.on_overlap_stop || self.options.on_overlap_start) {
this.manage_colliders_start_stop(colliders_coords,
self.options.on_overlap_stop, self.options.on_overlap_start);
}
this.last_colliders_coords = colliders_coords;
return colliders_data;
};
fn.get_closest_colliders = function(player_data_coords){
var colliders = this.find_collisions(player_data_coords);
var min_area = 100;
colliders.sort(function(a, b){
if (a.area <= min_area) {
return 1;
}
/* if colliders are being overlapped by the "C" (center) region,
* we have to set a lower index in the array to which they are placed
* above in the grid. */
if (a.region === 'C' && b.region === 'C') {
if (a.coords.y1 < b.coords.y1 || a.coords.x1 < b.coords.x1) {
return - 1;
}else{
return 1;
}
}
if (a.area < b.area){
return 1;
}
return 1;
});
return colliders;
};
//jQuery adapter
$.fn.collision = function(collider, options) {
return new Collision( this, collider, options );
};
}(jQuery, window, document));
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