added new helper methods

worked on gridWalker v3

geo/Circle2.h

@@ -5,6 +5,7 @@
 
 #include "Point2.h"
 #include "Ray2.h"
+#include "Line2.h"
 
 #include "../Assertions.h"
 
@@ -65,6 +66,24 @@ public:
 
 	}
 
+	/** does this circle intersect with the given ray? */
+	bool intersects(const Line2 line) const {
+
+		// https://math.stackexchange.com/questions/311921/get-location-of-vector-circle-intersection
+		Point2 dir = line.p2 - line.p1;
+		Point2 start = line.p1;
+		const float a = dir.x*dir.x + dir.y*dir.y;
+		const float b = 2 * dir.x * (start.x-center.x) + 2 * dir.y * (start.y - center.y);
+		const float c = (start.x-center.x) * (start.x-center.x) + (start.y - center.y)*(start.y - center.y) - radius*radius;
+		const float discr = b*b - 4*a*c;
+
+		if (discr < 0) {return false;}
+
+		const float t = (2*c) / (-b + std::sqrt(discr));
+		return (t <= 1) && (t >= 0);
+
+	}
+
 
 	/** configure this sphere to contain the given point-set */
 	void adjustToPointSet(const std::vector<Point2>& lst) {

geo/Heading.h

@@ -77,10 +77,10 @@ public:
 	}
 
 
-        Heading& operator = (const float _rad) {
-            rad = _rad;
-            return *this;
-        }
+		Heading& operator = (const float _rad) {
+			rad = _rad;
+			return *this;
+		}
 
 	/** compare two headings */
 	bool operator == (const Heading other) const {return rad == other.rad;}
@@ -95,6 +95,11 @@ public:
 
 	float getRAD() const {return rad;}
 
+	/** convert heading into a direction-vector */
+	Point2 asVector() const {
+		return Point2(std::cos(rad), std::sin(rad));
+	}
+
 //	/** get a random heading */
 //	static Heading rnd() {
 //		static std::minstd_rand gen(1234);