From 95eed94c9294f719724283e672cc7c83b2abd282 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Sun, 7 Jan 2024 01:10:26 +0000
Subject: Unified crossProduct

---
 game/geoData.cpp  |  2 +-
 gfx/gl/camera.cpp |  4 ++--
 lib/maths.h       | 20 +++++++++++++++++---
 lib/ray.cpp       |  5 +++--
 4 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/game/geoData.cpp b/game/geoData.cpp
index 97f4a26..816733f 100644
--- a/game/geoData.cpp
+++ b/game/geoData.cpp
@@ -161,7 +161,7 @@ namespace {
 	positionOnTriangle(const GlobalPosition2D point, const GeoData::Triangle<3> & t)
 	{
 		const CalcPosition3D a = t[1] - t[0], b = t[2] - t[0];
-		const auto n = crossInt(a, b);
+		const auto n = crossProduct(a, b);
 		return {point, ((n.x * t[0].x) + (n.y * t[0].y) + (n.z * t[0].z) - (n.x * point.x) - (n.y * point.y)) / n.z};
 	}
 
diff --git a/gfx/gl/camera.cpp b/gfx/gl/camera.cpp
index d362b94..0bc911a 100644
--- a/gfx/gl/camera.cpp
+++ b/gfx/gl/camera.cpp
@@ -31,8 +31,8 @@ Camera::updateView()
 Direction3D
 Camera::upFromForward(const Direction3D & forward)
 {
-	const auto right = glm::cross(forward, ::down);
-	return glm::cross(forward, right);
+	const auto right = crossProduct(forward, ::down);
+	return crossProduct(forward, right);
 }
 
 std::array<GlobalPosition4D, 4>
diff --git a/lib/maths.h b/lib/maths.h
index c1bf61a..b5af9ca 100644
--- a/lib/maths.h
+++ b/lib/maths.h
@@ -68,9 +68,9 @@ sq(T v)
 	return v * v;
 }
 
-template<std::integral T, glm::qualifier Q>
-inline constexpr glm::vec<3, T, Q>
-crossInt(const glm::vec<3, T, Q> a, const glm::vec<3, T, Q> b)
+template<glm::qualifier Q>
+inline constexpr glm::vec<3, int64_t, Q>
+crossProduct(const glm::vec<3, int64_t, Q> a, const glm::vec<3, int64_t, Q> b)
 {
 	return {
 			(a.y * b.z) - (a.z * b.y),
@@ -79,6 +79,20 @@ crossInt(const glm::vec<3, T, Q> a, const glm::vec<3, T, Q> b)
 	};
 }
 
+template<std::integral T, glm::qualifier Q>
+inline constexpr glm::vec<3, T, Q>
+crossProduct(const glm::vec<3, T, Q> a, const glm::vec<3, T, Q> b)
+{
+	return crossProduct<int64_t, Q>(a, b);
+}
+
+template<std::floating_point T, glm::qualifier Q>
+inline constexpr glm::vec<3, T, Q>
+crossProduct(const glm::vec<3, T, Q> a, const glm::vec<3, T, Q> b)
+{
+	return glm::cross(a, b);
+}
+
 template<typename R = float, typename Ta, typename Tb>
 inline constexpr auto
 ratio(Ta a, Tb b)
diff --git a/lib/ray.cpp b/lib/ray.cpp
index 9fb3648..254ad14 100644
--- a/lib/ray.cpp
+++ b/lib/ray.cpp
@@ -1,4 +1,5 @@
 #include "ray.h"
+#include "maths.h"
 #include <algorithm>
 
 Ray
@@ -14,8 +15,8 @@ Ray::distanceToLine(const Position3D & p1, const Position3D & e1) const
 	const auto diff = p1 - e1;
 	const auto d1 = glm::normalize(diff);
 	const auto &p2 = start, &d2 = direction;
-	const auto n = glm::cross(d1, d2);
-	const auto n2 = glm::cross(d2, n);
+	const auto n = crossProduct(d1, d2);
+	const auto n2 = crossProduct(d2, n);
 	const auto c1 = p1 + (glm::dot((p2 - p1), n2) / glm::dot(d1, n2)) * d1;
 	const auto difflength = glm::length(diff);
 	if (glm::length(c1 - p1) > difflength || glm::length(c1 - e1) > difflength) {
-- 
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