From db92ed183a8328a775323d7d4478397b907297d8 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Sun, 7 Mar 2021 18:55:28 +0000
Subject: Speed conversions and literals

---
 lib/maths.cpp | 10 ++++++++++
 lib/maths.h   | 19 +++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/lib/maths.cpp b/lib/maths.cpp
index 4ae0693..26eae47 100644
--- a/lib/maths.cpp
+++ b/lib/maths.cpp
@@ -173,3 +173,13 @@ find_arcs_radius(glm::vec2 start, glm::vec2 ad, glm::vec2 end, glm::vec2 bd)
 								   * (sq(m) - 2 * m * o + sq(o) + sq(n) - 2 * n * p + sq(p)))))
 			/ (2 * (sq(X) - 2 * X * Z + sq(Z) + sq(Y) - 2 * Y * W + sq(W) - 4));
 }
+
+float operator"" _mph(const long double v)
+{
+	return mph_to_ms(v);
+}
+
+float operator"" _kph(const long double v)
+{
+	return kph_to_ms(v);
+}
diff --git a/lib/maths.h b/lib/maths.h
index dc0c617..c4c1a51 100644
--- a/lib/maths.h
+++ b/lib/maths.h
@@ -87,4 +87,23 @@ std::pair<glm::vec2, bool> find_arc_centre(glm::vec2 start, glm::vec2 ad, glm::v
 std::pair<float, float> find_arcs_radius(glm::vec2 start, float entrys, glm::vec2 end, float entrye);
 float find_arcs_radius(glm::vec2 start, glm::vec2 ad, glm::vec2 end, glm::vec2 bd);
 
+// Conversions
+template<typename T>
+inline constexpr float
+mph_to_ms(T v)
+{
+	return v / 2.237;
+}
+
+template<typename T>
+inline constexpr float
+kph_to_ms(T v)
+{
+	return v / 3.6;
+}
+
+// ... literals are handy for now, probably go away when we load stuff externally
+float operator"" _mph(const long double v);
+float operator"" _kph(const long double v);
+
 #endif
-- 
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