X-Git-Url: http://git.localhorst.tv/?a=blobdiff_plain;f=src%2Fgeometry%2Fprimitive.hpp;h=b9f2187580f5b64e692451553a352c72006e7e42;hb=242b87a5fb412f9006e4b7debc1408cf7ac83000;hp=72da84749140ca6f2d6b2c71a069c3fd9c031199;hpb=fda38181732e58537331c919dd699eaa830ead50;p=blank.git

diff --git a/src/geometry/primitive.hpp b/src/geometry/primitive.hpp
index 72da847..b9f2187 100644
--- a/src/geometry/primitive.hpp
+++ b/src/geometry/primitive.hpp
@@ -4,6 +4,7 @@
 #include <algorithm>
 #include <iosfwd>
 #include <glm/glm.hpp>
+#include <glm/gtx/norm.hpp>
 
 
 namespace blank {
@@ -42,6 +43,19 @@ struct Ray {
 	void Update() noexcept {
 		inv_dir = 1.0f / dir;
 	}
+
+	/// get shortest distance of this ray's line to given point
+	float Distance(const glm::vec3 &point) const noexcept {
+		// d = |(x2-x1)×(x1-x0)|/|x2-x1|
+		// where x0 is point, and x1 and x2 are points on the line
+		// for derivation, see http://mathworld.wolfram.com/Point-LineDistance3-Dimensional.html
+		// x1 = orig
+		// x2-x1 = dir, which means |x2-x1| is 1.0
+		return length(cross(dir, orig - point));
+	}
+	float DistanceSquared(const glm::vec3 &point) const noexcept {
+		return length2(cross(dir, orig - point));
+	}
 };
 
 std::ostream &operator <<(std::ostream &, const Ray &);