Phaser.Line.intersectsRectangle checks for intersection between a Line and a Rectangle, or any Rectangle-like object such as a Sprite or Body.

README.md

@@ -336,7 +336,7 @@ You can read all about the philosophy behind Lazer [here](http://phaser.io/news/
 
 ### New Features
 
-*
+* Phaser.Line.intersectsRectangle checks for intersection between a Line and a Rectangle, or any Rectangle-like object such as a Sprite or Body.
 *
 *
 

src/geom/Line.js

@@ -627,6 +627,98 @@ Phaser.Line.intersects = function (a, b, asSegment, result) {
 
 };
 
+/**
+* Checks for intersection between the Line and a Rectangle shape, or a rectangle-like
+* object, with public `x`, `y`, `right` and `bottom` properties, such as a Sprite or Body.
+* 
+* An intersection is considered valid if:
+* 
+* The line starts within, or ends within, the Rectangle.
+* The line segment intersects one of the 4 rectangle edges.
+* 
+* The for the purposes of this function rectangles are considered 'solid'.
+*
+* @method intersectsRectangle
+* @param {Phaser.Line} line - The line to check for intersection with.
+* @param {Phaser.Rectangle|object} rect - The rectangle, or rectangle-like object, to check for intersection with.
+* @return {boolean} True if the line intersects with the rectangle edges, or starts or ends within the rectangle.
+*/
+Phaser.Line.intersectsRectangle = function (line, rect) {
+
+    //  Quick bail out of the Line and Rect bounds don't intersect
+    if (!Phaser.Rectangle.intersects(line, rect))
+    {
+        return false;
+    }
+
+    var x1 = line.start.x;
+    var y1 = line.start.y;
+
+    var x2 = line.end.x;
+    var y2 = line.end.y;
+
+    var bx1 = rect.x;
+    var by1 = rect.y;
+    var bx2 = rect.right;
+    var by2 = rect.bottom;
+
+    var t = 0;
+
+    //  If the start or end of the line is inside the rect then we assume
+    //  collision, as rects are solid for our use-case.
+
+    if ((x1 >= bx1 && x1 <= bx2 && y1 >= by1 && y1 <= by2) || 
+        (x2 >= bx1 && x2 <= bx2 && y2 >= by1 && y2 <= by2))
+    {
+        return true;
+    }
+
+    if (x1 < bx1 && x2 >= bx1)
+    {
+        //  Left edge
+        t = y1 + (y2 - y1) * (bx1 - x1) / (x2 - x1);
+
+        if (t > by1 && t <= by2)
+        {
+            return true;
+        }
+    }
+    else if (x1 > bx2 && x2 <= bx2)
+    {
+        //  Right edge
+        t = y1 + (y2 - y1) * (bx2 - x1) / (x2 - x1);
+
+        if (t >= by1 && t <= by2)
+        {
+            return true;
+        }
+    }
+
+    if (y1 < by1 && y2 >= by1)
+    {
+        //  Top edge
+        t = x1 + (x2 - x1) * (by1 - y1) / (y2 - y1);
+
+        if (t >= bx1 && t <= bx2)
+        {
+            return true;
+        }
+    }
+    else if (y1 > by2 && y2 <= by2)
+    {
+        //  Bottom edge
+        t = x1 + (x2 - x1) * (by2 - y1) / (y2 - y1);
+
+        if (t >= bx1 && t <= bx2)
+        {
+            return true;
+        }
+    }
+
+    return false;
+
+};
+
 /**
 * Returns the reflected angle between two lines.
 * This is the outgoing angle based on the angle of Line 1 and the normalAngle of Line 2.