X-Git-Url: http://git.localhorst.tv/?a=blobdiff_plain;f=src%2Fgeometry%2Fprimitive.hpp;h=b9f2187580f5b64e692451553a352c72006e7e42;hb=242b87a5fb412f9006e4b7debc1408cf7ac83000;hp=da4c37f1e03296d254d55f051d5e199f94132a9c;hpb=1e93bfb5089737f6b6d8fdd2f17260944fca44b2;p=blank.git

diff --git a/src/geometry/primitive.hpp b/src/geometry/primitive.hpp
index da4c37f..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 {
@@ -31,13 +32,42 @@ struct AABB {
 
 std::ostream &operator <<(std::ostream &, const AABB &);
 
+// TODO: this should really use setters/getters for dir and inv_dir so
+//       manipulating code doesn't "forget" to call Update()
 struct Ray {
 	glm::vec3 orig;
 	glm::vec3 dir;
+
+	glm::vec3 inv_dir;
+
+	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 &);
 
+/// axis aligned boolean ray/box intersection test
+/// if true, dist constains distance from ray's origin to intersection point
+bool Intersection(
+	const Ray &,
+	const AABB &,
+	float &dist) noexcept;
+
+/// detailed oriented ray/box intersection test
 bool Intersection(
 	const Ray &,
 	const AABB &,