1 files changed, 81 insertions, 8 deletions

diff --git a/public/assets/javascripts/rectangles/models/vec2.js b/public/assets/javascripts/rectangles/models/vec2.js
index 9233aec..2bf286b 100644
--- a/public/assets/javascripts/rectangles/models/vec2.js
+++ b/public/assets/javascripts/rectangles/models/vec2.js
@@ -1,4 +1,6 @@
 (function(){
+	function clamp(n,a,b){ return n<a?a:n<b?n:b }
+
 	var vec2 = function (a,b){
 		this.a = a
 		this.b = b
@@ -7,7 +9,7 @@
 		return this.b-this.a
 	}
 	vec2.prototype.length = function(){
-		return abs(this.b-this.a)
+		return Math.abs(this.b-this.a)
 	}
 	vec2.prototype.dist = function(){
 		return dist(0,this.a,0,this.b)
@@ -70,6 +72,9 @@
 	vec2.prototype.contains = function(n){
 		return this.a <= n && n <= this.b
 	}
+	vec2.prototype.containsCenter = function(n){
+		return this.a < n && n < this.b
+	}
 	vec2.prototype.containsDisc = function(n,r){
 		return this.a <= n-r && n+r <= this.b
 	}
@@ -80,16 +85,35 @@
 		return clamp(n, this.a+r, this.b-r)
 	}
 	vec2.prototype.intersects = function(v){
-		if (this.a < v.a) {
-			return (v.a < this.b && this.b <= v.b) || (this.a < v.b && v.b <= this.b)
-		}
-		else if (this.a == v.a) {
+		if (this.a == v.a || this.b == v.b || this.a == v.b || this.b == v.a) {
 			return true
 		}
+		else if (this.a < v.a) {
+			return (v.a < this.b && this.b <= v.b) || (this.a < v.b && v.b <= this.b)
+		}
 		else if (this.a > v.a) {
 			return (this.a < v.b && v.b <= this.b) || (v.a < this.b && this.b <= v.b)
 		}
 	}
+	vec2.prototype.overlaps = function(v){
+		if (this.a == v.a || this.b == v.b) {
+			return true
+		}
+		if (this.a < v.a) {
+			return (v.a < this.b && this.b < v.b) || (this.a < v.b && v.b < this.b)
+		}
+		else if (v.a < this.a) {
+			return (this.a < v.b && v.b < this.b) || (v.a < this.b && this.b < v.b)
+		}
+	}
+
+
+	vec2.prototype.adjacent = function(v){
+		if (this.a == v.a || this.b == v.b || this.a == v.b || this.b == v.a) {
+			return true
+		}
+		return false
+	}
 	vec2.prototype.union = function(v){
 		if (this.intersects(v)) {
 			return new vec2( min(this.a,v.a), max(this.b, v.b) )
@@ -100,6 +124,56 @@
 			return new vec2( max(this.a,v.a), min(this.b, v.b) )
 		}
 	}
+
+	// given two vectors, test how they overlap
+	// return the set of overlapping segments in the initial vector, labelled with sides
+	vec2.prototype.split = function(v, left, right){
+		var intervals = [], _len
+
+		if (this.eq(v)) {
+			intervals.push([ new vec2( this.a, this.b ), left | right ])
+		}
+		
+		// a---A===b---B  (rightways overlap)
+		else if (this.contains(v.a) && v.contains(this.b)) {
+			intervals.push([ new vec2( this.a,    v.a ), left  ])
+			intervals.push([ new vec2(    v.a, this.b ), right ])
+		}
+
+    // A---a===B---b  (leftways overlap)
+		else if (v.contains(this.a) && this.contains(v.b)) {
+			intervals.push([ new vec2( this.a,    v.b ), left  ])
+			intervals.push([ new vec2(    v.b, this.b ), right ])
+		}
+	
+		// a---A===B---b  (contains v)
+		else if (this.contains(v.a) && this.contains(v.b)) {
+			intervals.push([ new vec2( this.a,    v.a ), left  ])
+			intervals.push([ new vec2(    v.a, 	  v.b ), 0     ])
+			intervals.push([ new vec2(    v.b, this.b ), right ])
+		}
+		
+		// A---a===b---B  (contained in v)
+		else { // if (v.contains(this.a) && v.contains(v.b)) {
+			intervals.push([ new vec2( this.a, this.b ), left | right ])
+		}
+		
+		// cull empty vectors
+		_len = intervals.length
+		if (_len > 1) {
+			if (intervals[0][0].magnitude() == 0) {
+				intervals[1][1] |= intervals[0][1]
+				intervals.shift()
+			}
+			else if (intervals[_len-1][0].magnitude() == 0) {
+				intervals[_len-2][1] |= intervals[_len-1][1]
+				intervals.pop()
+			}
+		}
+		
+		return intervals
+	}
+
 	vec2.prototype.toString = function(){
 		return "[" + ~~this.a + " " + ~~this.b + "]"
 	}
@@ -115,8 +189,7 @@
 	if ('window' in this) {
 		window.vec2 = vec2
 	}
-	else if ('module' in this) {
+	else {
 		module.exports = vec2
 	}
-	
-})()
\ No newline at end of file
+})()