new helper methods

adjusted wall intersection

geo/Line2.h

@@ -45,6 +45,18 @@ public:
 		return p1.getDistance(p2);
 	}
 
+	/** keep the starting point, but make the line longer by the given length */
+	Line2 longerAtEnd(const float l) {
+		Point2 dir = p2-p1;
+		return Line2(p1, p1+dir+dir.normalized()*l);
+	}
+
+	/** keep the ending point, but make the line longer by the given length */
+	Line2 longerAtStart(const float l) {
+		Point2 dir = p1-p2;
+		return Line2(p2, p2+dir+dir.normalized()*l);
+	}
+
 	/** get intersection between these two lines (unlimited length!) */
 	bool getLineIntersection(const Line2& other, Point2& result) const {
 

geo/Point2.h

@@ -44,6 +44,7 @@ struct Point2 {
 
 	bool operator != (const Point2& o) const {return x!=o.x || y!=o.y;}
 
+	bool eq (const Point2& o, const float delta) const { return eq(x,o.x,delta) && eq(y,o.y,delta); }
 
 	Point2 perpendicular() const {return Point2(-y, x);}
 
@@ -66,6 +67,11 @@ struct Point2 {
 		return "(" + std::to_string(x) + "," + std::to_string(y) + ")";
 	}
 
+private:
+
+	static inline bool eq(const float a, const float b, const float delta) {return std::abs(a-b) <= delta;}
+	static inline bool ne(const float a, const float b, const float delta) {return std::abs(a-b)  > delta;}
+
 };
 
 inline float dot(const Point2 p1, const Point2 p2) {