From 84358a17c18aa8e23f9508f4fa3a864e27d51697 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Thu, 24 Apr 2025 01:31:27 +0100
Subject: Avoid out parameters with Ray::intersectTriangle

---
 game/geoData.cpp              |  6 ++----
 game/vehicles/railVehicle.cpp |  9 +++++++--
 lib/ray.h                     | 22 +++++++++++++++++-----
 3 files changed, 26 insertions(+), 11 deletions(-)

diff --git a/game/geoData.cpp b/game/geoData.cpp
index db0f3f4..b886efd 100644
--- a/game/geoData.cpp
+++ b/game/geoData.cpp
@@ -121,11 +121,9 @@ GeoData::intersectRay(const Ray<GlobalPosition3D> & ray, FaceHandle face) const
 	walkUntil(PointFace {ray.start, face},
 			ray.start.xy() + (ray.direction.xy() * ::difference(extents.max.xy(), extents.min.xy())),
 			[&out, &ray, this](const auto & step) {
-				BaryPosition bari {};
-				RelativeDistance dist {};
 				const auto t = triangle<3>(step.current);
-				if (ray.intersectTriangle(t.x, t.y, t.z, bari, dist)) {
-					out.emplace(t * bari, step.current);
+				if (const auto inter = ray.intersectTriangle(t.x, t.y, t.z)) {
+					out.emplace(t * inter->bary, step.current);
 					return true;
 				}
 				return false;
diff --git a/game/vehicles/railVehicle.cpp b/game/vehicles/railVehicle.cpp
index 59d1e83..4a0a22d 100644
--- a/game/vehicles/railVehicle.cpp
+++ b/game/vehicles/railVehicle.cpp
@@ -72,7 +72,12 @@ RailVehicle::intersectRay(const Ray<GlobalPosition3D> & ray, BaryPosition & bary
 	}};
 	return std::any_of(
 			triangles.begin(), triangles.end(), [&cornerVertices, &ray, &baryPos, &distance](const auto & idx) {
-				return ray.intersectTriangle(
-						cornerVertices[idx[0]], cornerVertices[idx[1]], cornerVertices[idx[2]], baryPos, distance);
+				if (const auto inter = ray.intersectTriangle(
+							cornerVertices[idx[0]], cornerVertices[idx[1]], cornerVertices[idx[2]])) {
+					baryPos = inter->bary;
+					distance = inter->distance;
+					return true;
+				};
+				return false;
 			});
 }
diff --git a/lib/ray.h b/lib/ray.h
index 793e21e..2b117b7 100644
--- a/lib/ray.h
+++ b/lib/ray.h
@@ -53,17 +53,29 @@ public:
 		}
 	}
 
-	bool
-	intersectTriangle(const PositionType t0, const PositionType t1, const PositionType t2, BaryPosition & bary,
-			RelativeDistance & distance) const
+	struct IntersectTriangleResult {
+		BaryPosition bary;
+		RelativeDistance distance;
+	};
+
+	std::optional<IntersectTriangleResult>
+	intersectTriangle(const PositionType t0, const PositionType t1, const PositionType t2) const
 	{
+		IntersectTriangleResult out;
 		if constexpr (std::is_floating_point_v<typename PositionType::value_type>) {
-			return glm::intersectRayTriangle(start, direction, t0, t1, t2, bary, distance) && distance >= 0.F;
+			if (glm::intersectRayTriangle(start, direction, t0, t1, t2, out.bary, out.distance)
+					&& out.distance >= 0.F) {
+				return out;
+			}
 		}
 		else {
 			const RelativePosition3D t0r = t0 - start, t1r = t1 - start, t2r = t2 - start;
-			return glm::intersectRayTriangle({}, direction, t0r, t1r, t2r, bary, distance) && distance >= 0.F;
+			if (glm::intersectRayTriangle({}, direction, t0r, t1r, t2r, out.bary, out.distance)
+					&& out.distance >= 0.F) {
+				return out;
+			}
 		}
+		return std::nullopt;
 	}
 
 	bool
-- 
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