AABB intersection, handling most cases

1 files changed, 54 insertions, 11 deletions

diff --git a/rect.js b/rect.js
index f643b6f..19e69b7 100644
--- a/rect.js
+++ b/rect.js
@@ -23,8 +23,8 @@ rect.prototype.area = function(){
 	return this.x.length() * this.y.length()
 }
 rect.prototype.normalize = function(){
-	this.x.normalize().add(this.translation.a)
-	this.y.normalize().add(this.translation.b)
+	this.x.abs().add(this.translation.a)
+	this.y.abs().add(this.translation.b)
 	this.translation.a = this.translation.b = 0
 	return this
 }
@@ -65,26 +65,69 @@ rect.prototype.reset = function(){
 }
 rect.prototype.clipTo = function(r){
 	// for each of this rect's regions split the region if necessary
+	var regions = this.regions
+	var splits
 	for (var i = 0, len = regions.length; i < len; i++) {
 		if (regions[i] && regions[i].intersects(r)) {
-			var splits = regions[i].split(r)
-			regions.concat(splits)
+			splits = regions[i].split(r)
+			regions = regions.concat(splits)
 			regions[i] = null
 		}
 	}
+	this.regions = regions
 }
 rect.prototype.split = function(r){
 	var splits = []
+	var x_intervals = [], y_intervals = []
 
+	// Split vertically
+	if (this.x.contains(r.x.a) && r.x.contains(this.x.b)) {
+		x_intervals.push( new vec2( this.x.a,    r.x.a ))
+		x_intervals.push( new vec2(    r.x.a, this.x.b ))
+	}
+
+	else if (r.x.contains(this.x.a) && this.x.contains(r.x.b)) {
+		x_intervals.push( new vec2( this.x.a,    r.x.b ))
+		x_intervals.push( new vec2(    r.x.b, this.x.b ))
+	}
 	
+	else if (this.x.contains(r.x.a) && this.x.contains(r.x.b)) {
+		x_intervals.push( new vec2( this.x.a,    r.x.a ))
+		x_intervals.push( new vec2(    r.x.a, 	 r.x.b ))
+		x_intervals.push( new vec2(    r.x.b, this.x.b ))
+	}
+
+	else if (r.x.contains(this.x.a) && r.x.contains(r.x.b)) {
+		x_intervals.push( new vec2( this.x.a, this.x.b ))
+	}
+
+
+	// Split horizontally
+	if (this.y.contains(r.y.a) && r.y.contains(this.y.b)) {
+		y_intervals.push( new vec2( this.y.a,    r.y.a ))
+		y_intervals.push( new vec2(    r.y.a, this.y.b ))
+	}
+
+	else if (r.y.contains(this.y.a) && this.y.contains(r.y.b)) {
+		y_intervals.push( new vec2( this.y.a,    r.y.b ))
+		y_intervals.push( new vec2(    r.y.b, this.y.b ))
+	}
+	
+	else if (this.y.contains(r.y.a) && this.y.contains(r.y.b)) {
+		y_intervals.push( new vec2( this.y.a,    r.y.a ))
+		y_intervals.push( new vec2(    r.y.a, 	 r.y.b ))
+		y_intervals.push( new vec2(    r.y.b, this.y.b ))
+	}
+
+	else if (r.y.contains(this.y.a) && this.y.contains(r.y.b)) {
+		y_intervals.push( new vec2( this.y.a, this.y.b ))
+	}
 
-	// 1 split (horizontal)
-	// 1 split (vertical)
-	// 2 splits (top left)
-	// 2 splits (top right)
-	// 2 splits (bottom left)
-	// 2 splits (bottom right)
-	// 3 splits (center)
+	x_intervals.forEach(function(x){
+		y_intervals.forEach(function(y){
+			splits.push(new rect(x,y))
+		})
+	})
 
 	return splits
 }