new bbox features (2D, 3D)

added stair-sanitizing code
adjusted walkers

geo/BBox3.h

@@ -49,6 +49,28 @@ public:
 				(p2.z == o.p2.z);
 	}
 
+	/** shrink the bbox in each dimension by the given amount */
+	void shrink(const float v) {
+		shrink(Point3(v,v,v));
+	}
+
+	/** shrink the bbox by the amount given for each dimension */
+	void shrink(const Point3& p) {
+		p1 += p;	// increase minimum
+		p2 -= p;	// decrease maximum
+	}
+
+	/** does the bbox contain the given point? */
+	bool contains(const Point3& p) const {
+		if (p.x < p1.x) {return false;}
+		if (p.x > p2.x) {return false;}
+		if (p.y < p1.y) {return false;}
+		if (p.y > p2.y) {return false;}
+		if (p.z < p1.z) {return false;}
+		if (p.z > p2.z) {return false;}
+		return true;
+	}
+
 };
 
 #endif // BBOX3_H