From 1aba027462a861f2c1155672792dbbe555d7dc0a Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Mon, 13 Jan 2025 01:45:43 +0000
Subject: Add distance helper

Works with integer positions, first template param allows forcing to N dimensions
---
 lib/maths.h    | 9 ++++++++-
 lib/ray.h      | 3 +--
 lib/triangle.h | 2 +-
 3 files changed, 10 insertions(+), 4 deletions(-)

(limited to 'lib')

diff --git a/lib/maths.h b/lib/maths.h
index 17ca795..3d4f440 100644
--- a/lib/maths.h
+++ b/lib/maths.h
@@ -111,6 +111,13 @@ difference(const glm::vec<D, T, Q> & globalA, const glm::vec<D, T, Q> & globalB)
 	return globalA - globalB;
 }
 
+template<glm::length_t D, Arithmetic T, glm::qualifier Q = glm::defaultp>
+constexpr auto
+distance(const glm::vec<D, T, Q> & pointA, const glm::vec<D, T, Q> & pointB)
+{
+	return glm::length(difference(pointA, pointB));
+}
+
 glm::mat4 flat_orientation(const Rotation3D & diff);
 
 namespace {
@@ -498,7 +505,7 @@ operator"" _degrees(long double degrees)
 // Late implementations due to dependencies
 template<typename T, glm::qualifier Q>
 constexpr ArcSegment<T, Q>::ArcSegment(PointType centre, PointType ep0, PointType ep1) :
-	Arc {centre, ep0, ep1}, centre {centre}, ep0 {ep0}, ep1 {ep1}, radius {glm::length(difference(centre, ep0))}
+	Arc {centre, ep0, ep1}, centre {centre}, ep0 {ep0}, ep1 {ep1}, radius {::distance(centre, ep0)}
 {
 }
 
diff --git a/lib/ray.h b/lib/ray.h
index a831270..793e21e 100644
--- a/lib/ray.h
+++ b/lib/ray.h
@@ -27,8 +27,7 @@ public:
 		const auto n2 = crossProduct(direction, n);
 		const auto c1 = p1 + PositionType((glm::dot(RelativePosition3D(start - p1), n2) / glm::dot(d1, n2)) * d1);
 		const auto difflength = glm::length(diff);
-		if (glm::length(RelativePosition3D(c1 - p1)) > difflength
-				|| glm::length(RelativePosition3D(c1 - e1)) > difflength) {
+		if (::distance(c1, p1) > difflength || ::distance(c1, e1) > difflength) {
 			return std::numeric_limits<typename PositionType::value_type>::infinity();
 		}
 		return static_cast<PositionType::value_type>(glm::abs(glm::dot(n, RelativePosition3D(p1 - start))));
diff --git a/lib/triangle.h b/lib/triangle.h
index d5547ab..e430653 100644
--- a/lib/triangle.h
+++ b/lib/triangle.h
@@ -48,7 +48,7 @@ struct Triangle : public glm::vec<3, glm::vec<Dim, T, Q>> {
 	[[nodiscard]] constexpr auto
 	height()
 	{
-		return (area() * 2) / glm::length(difference(p(0), p(1)));
+		return (area() * 2) / ::distance(p(0), p(1));
 	}
 
 	[[nodiscard]] constexpr Normal3D
-- 
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