Merge branch 'global-network'

7 files changed, 104 insertions, 107 deletions

diff --git a/game/network/link.cpp b/game/network/link.cpp
index e8eaea2..932fc67 100644
--- a/game/network/link.cpp
+++ b/game/network/link.cpp
@@ -1,5 +1,4 @@
 #include "link.h"
-#include <compare>
 #include <glm/gtx/transform.hpp>
 #include <location.h>
 #include <maths.h>
@@ -8,10 +7,10 @@
 
 Link::Link(End a, End b, float l) : ends {{std::move(a), std::move(b)}}, length {l} { }
 
-LinkCurve::LinkCurve(Position3D c, float r, Arc a) : centreBase {c}, radius {r}, arc {std::move(a)} { }
+LinkCurve::LinkCurve(GlobalPosition3D c, RelativeDistance r, Arc a) : centreBase {c}, radius {r}, arc {std::move(a)} { }
 
 bool
-operator<(const Position3D & a, const Position3D & b)
+operator<(const GlobalPosition3D & a, const GlobalPosition3D & b)
 {
 	// NOLINTNEXTLINE(hicpp-use-nullptr,modernize-use-nullptr)
 	return std::tie(a.x, a.y, a.z) < std::tie(b.x, b.y, b.z);
@@ -24,12 +23,13 @@ operator<(const Node & a, const Node & b)
 }
 
 Location
-LinkStraight::positionAt(float dist, unsigned char start) const
+LinkStraight::positionAt(RelativeDistance dist, unsigned char start) const
 {
 	const auto es {std::make_pair(ends[start].node.get(), ends[1 - start].node.get())};
-	const auto diff {es.second->pos - es.first->pos};
+	const RelativePosition3D diff {es.second->pos - es.first->pos};
 	const auto dir {glm::normalize(diff)};
-	return Location {es.first->pos + vehiclePositionOffset() + dir * dist, {vector_pitch(dir), vector_yaw(dir), 0}};
+	return Location {es.first->pos + GlobalPosition3D(vehiclePositionOffset() + dir * dist),
+			{vector_pitch(dir), vector_yaw(dir), 0}};
 }
 
 bool
@@ -49,9 +49,11 @@ LinkCurve::positionAt(float dist, unsigned char start) const
 	const auto ang {as.first + ((as.second - as.first) * frac)};
 	const auto relPos {(sincosf(ang) || 0.F) * radius};
 	const auto relClimb {vehiclePositionOffset()
-			+ Position3D {0, 0, es.first->pos.z - centreBase.z + ((es.second->pos.z - es.first->pos.z) * frac)}};
-	const auto pitch {vector_pitch({0, 0, (es.second->pos.z - es.first->pos.z) / length})};
-	return Location {relPos + relClimb + centreBase, {pitch, normalize(ang + dirOffset[start]), 0}};
+			+ RelativePosition3D {0, 0,
+					static_cast<RelativeDistance>(es.first->pos.z - centreBase.z)
+							+ (static_cast<RelativeDistance>(es.second->pos.z - es.first->pos.z) * frac)}};
+	const auto pitch {vector_pitch({0, 0, static_cast<RelativeDistance>(es.second->pos.z - es.first->pos.z) / length})};
+	return Location {GlobalPosition3D(relPos + relClimb) + centreBase, {pitch, normalize(ang + dirOffset[start]), 0}};
 }
 
 bool
@@ -61,15 +63,14 @@ LinkCurve::intersectRay(const Ray<GlobalPosition3D> & ray) const
 	const auto & e1p {ends[1].node->pos};
 	const auto slength = round_frac(length / 2.F, 5.F);
 	const auto segs = std::round(15.F * slength / std::pow(radius, 0.7F));
-	const auto step {Position3D {arc_length(arc), e1p.z - e0p.z, slength} / segs};
-	const auto trans {glm::translate(centreBase)};
+	const auto step {glm::vec<2, RelativeDistance> {arc_length(arc), e1p.z - e0p.z} / segs};
 
 	auto segCount = static_cast<std::size_t>(std::lround(segs)) + 1;
 	std::vector<GlobalPosition3D> points;
 	points.reserve(segCount);
-	for (Position3D swing = {arc.first, centreBase.z - e0p.z, 0.F}; segCount; swing += step, --segCount) {
-		const auto t {trans * glm::rotate(half_pi - swing.x, up) * glm::translate(Position3D {radius, 0.F, swing.y})};
-		points.emplace_back(t * glm::vec4 {0, 0, 0, 1});
+	for (std::remove_const_t<decltype(step)> swing = {arc.first, centreBase.z - e0p.z}; segCount;
+			swing += step, --segCount) {
+		points.emplace_back(centreBase + GlobalPosition3D((sincosf(swing.x) * radius) || swing.y));
 	}
 	return ray.passesCloseToEdges(points, 1.F);
 }
diff --git a/game/network/link.h b/game/network/link.h
index 95c141e..725e023 100644
--- a/game/network/link.h
+++ b/game/network/link.h
@@ -4,7 +4,6 @@
 #include <glm/glm.hpp>
 #include <location.h>
 #include <maths.h>
-#include <memory>
 #include <special_members.h>
 #include <stdTypeDefs.h>
 #include <utility>
@@ -17,12 +16,12 @@ template<typename> class Ray;
 // it has location
 class Node : public StdTypeDefs<Node> {
 public:
-	explicit Node(Position3D p) noexcept : pos(p) {};
+	explicit Node(GlobalPosition3D p) noexcept : pos(p) {};
 	virtual ~Node() noexcept = default;
 	NO_COPY(Node);
 	NO_MOVE(Node);
 
-	Position3D pos;
+	GlobalPosition3D pos;
 };
 
 // Generic network link
@@ -44,21 +43,21 @@ public:
 	NO_COPY(Link);
 	NO_MOVE(Link);
 
-	[[nodiscard]] virtual Location positionAt(float dist, unsigned char start) const = 0;
+	[[nodiscard]] virtual Location positionAt(RelativeDistance dist, unsigned char start) const = 0;
 	[[nodiscard]] virtual bool intersectRay(const Ray<GlobalPosition3D> &) const = 0;
 
 	std::array<End, 2> ends;
 	float length;
 
 protected:
-	[[nodiscard]] virtual Position3D
+	[[nodiscard]] virtual RelativePosition3D
 	vehiclePositionOffset() const
 	{
 		return {};
 	}
 };
 
-bool operator<(const Position3D & a, const Position3D & b);
+bool operator<(const GlobalPosition3D & a, const GlobalPosition3D & b);
 bool operator<(const Node & a, const Node & b);
 
 class LinkStraight : public virtual Link {
@@ -68,7 +67,7 @@ public:
 	NO_COPY(LinkStraight);
 	NO_MOVE(LinkStraight);
 
-	[[nodiscard]] Location positionAt(float dist, unsigned char start) const override;
+	[[nodiscard]] Location positionAt(RelativeDistance dist, unsigned char start) const override;
 	[[nodiscard]] bool intersectRay(const Ray<GlobalPosition3D> &) const override;
 };
 
@@ -77,15 +76,15 @@ LinkStraight::~LinkStraight() = default;
 class LinkCurve : public virtual Link {
 public:
 	inline ~LinkCurve() override = 0;
-	LinkCurve(Position3D, float, Arc);
+	LinkCurve(GlobalPosition3D, RelativeDistance, Arc);
 	NO_COPY(LinkCurve);
 	NO_MOVE(LinkCurve);
 
-	[[nodiscard]] Location positionAt(float dist, unsigned char start) const override;
+	[[nodiscard]] Location positionAt(RelativeDistance dist, unsigned char start) const override;
 	[[nodiscard]] bool intersectRay(const Ray<GlobalPosition3D> &) const override;
 
-	Position3D centreBase;
-	float radius;
+	GlobalPosition3D centreBase;
+	RelativeDistance radius;
 	Arc arc;
 };
 
diff --git a/game/network/network.cpp b/game/network/network.cpp
index d52e804..8aa9adb 100644
--- a/game/network/network.cpp
+++ b/game/network/network.cpp
@@ -6,7 +6,6 @@
 #include <game/network/link.h>
 #include <gfx/models/texture.h>
 #include <glm/gtx/intersect.hpp>
-#include <initializer_list>
 #include <ray.h>
 #include <stdexcept>
 #include <utility>
@@ -14,13 +13,13 @@
 Network::Network(const std::string & tn) : texture {Texture::cachedTexture.get(tn)} { }
 
 Node::Ptr
-Network::nodeAt(Position3D pos)
+Network::nodeAt(GlobalPosition3D pos)
 {
 	return newNodeAt(pos).first;
 }
 
 Network::NodeInsertion
-Network::newNodeAt(Position3D pos)
+Network::newNodeAt(GlobalPosition3D pos)
 {
 	if (auto [n, i] = candidateNodeAt(pos); i == NodeIs::NotInNetwork) {
 		return {*nodes.insert(std::move(n)).first, i};
@@ -31,7 +30,7 @@ Network::newNodeAt(Position3D pos)
 }
 
 Node::Ptr
-Network::findNodeAt(Position3D pos) const
+Network::findNodeAt(GlobalPosition3D pos) const
 {
 	if (const auto n = nodes.find(pos); n != nodes.end()) {
 		return *n;
@@ -40,7 +39,7 @@ Network::findNodeAt(Position3D pos) const
 }
 
 Network::NodeInsertion
-Network::candidateNodeAt(Position3D pos) const
+Network::candidateNodeAt(GlobalPosition3D pos) const
 {
 	if (const auto n = nodes.find(pos); n != nodes.end()) {
 		return {*n, NodeIs::InNetwork};
@@ -80,7 +79,7 @@ Network::joinLinks(const Link::Ptr & l, const Link::Ptr & ol)
 }
 
 Link::Nexts
-Network::routeFromTo(const Link::End & start, Position3D dest) const
+Network::routeFromTo(const Link::End & start, GlobalPosition3D dest) const
 {
 	auto destNode {findNodeAt(dest)};
 	if (!destNode) {
@@ -96,7 +95,7 @@ Network::routeFromTo(const Link::End & end, const Node::Ptr & dest) const
 }
 
 GenCurveDef
-Network::genCurveDef(const Position3D & start, const Position3D & end, float startDir)
+Network::genCurveDef(const GlobalPosition3D & start, const GlobalPosition3D & end, float startDir)
 {
 	const auto diff {end - start};
 	const auto vy {vector_yaw(diff)};
@@ -112,28 +111,29 @@ Network::genCurveDef(const Position3D & start, const Position3D & end, float sta
 }
 
 std::pair<GenCurveDef, GenCurveDef>
-Network::genCurveDef(const Position3D & start, const Position3D & end, float startDir, float endDir)
+Network::genCurveDef(const GlobalPosition3D & start, const GlobalPosition3D & end, float startDir, float endDir)
 {
 	startDir += pi;
 	endDir += pi;
-	const Position2D flatStart {start.xy()}, flatEnd {end.xy()};
+	const auto flatStart {start.xy()}, flatEnd {end.xy()};
 	auto midheight = [&](auto mid) {
-		const auto sm = glm::distance(flatStart, mid), em = glm::distance(flatEnd, mid);
-		return start.z + ((end.z - start.z) * (sm / (sm + em)));
+		const auto sm = glm::length(RelativePosition2D(flatStart - mid)),
+				   em = glm::length(RelativePosition2D(flatEnd - mid));
+		return start.z + GlobalDistance(RelativeDistance(end.z - start.z) * (sm / (sm + em)));
 	};
 	if (const auto radii = find_arcs_radius(flatStart, startDir, flatEnd, endDir); radii.first < radii.second) {
 		const auto radius {radii.first};
-		const auto c1 = flatStart + sincosf(startDir + half_pi) * radius;
-		const auto c2 = flatEnd + sincosf(endDir + half_pi) * radius;
-		const auto mid = (c1 + c2) / 2.F;
+		const auto c1 = flatStart + GlobalPosition2D(sincosf(startDir + half_pi) * radius);
+		const auto c2 = flatEnd + GlobalPosition2D(sincosf(endDir + half_pi) * radius);
+		const auto mid = (c1 + c2) / 2;
 		const auto midh = mid || midheight(mid);
 		return {{start, midh, c1}, {end, midh, c2}};
 	}
 	else {
 		const auto radius {radii.second};
-		const auto c1 = flatStart + sincosf(startDir - half_pi) * radius;
-		const auto c2 = flatEnd + sincosf(endDir - half_pi) * radius;
-		const auto mid = (c1 + c2) / 2.F;
+		const auto c1 = flatStart + GlobalPosition2D(sincosf(startDir - half_pi) * radius);
+		const auto c2 = flatEnd + GlobalPosition2D(sincosf(endDir - half_pi) * radius);
+		const auto mid = (c1 + c2) / 2;
 		const auto midh = mid || midheight(mid);
 		return {{midh, start, c1}, {midh, end, c2}};
 	}
diff --git a/game/network/network.h b/game/network/network.h
index 9ce6e81..fa311ac 100644
--- a/game/network/network.h
+++ b/game/network/network.h
@@ -26,32 +26,32 @@ public:
 	virtual ~Network() = default;
 	DEFAULT_MOVE_NO_COPY(Network);
 
-	[[nodiscard]] Node::Ptr findNodeAt(Position3D) const;
-	[[nodiscard]] Node::Ptr nodeAt(Position3D);
+	[[nodiscard]] Node::Ptr findNodeAt(GlobalPosition3D) const;
+	[[nodiscard]] Node::Ptr nodeAt(GlobalPosition3D);
 	enum class NodeIs { InNetwork, NotInNetwork };
 	using NodeInsertion = std::pair<Node::Ptr, NodeIs>;
-	[[nodiscard]] NodeInsertion newNodeAt(Position3D);
-	[[nodiscard]] NodeInsertion candidateNodeAt(Position3D) const;
+	[[nodiscard]] NodeInsertion newNodeAt(GlobalPosition3D);
+	[[nodiscard]] NodeInsertion candidateNodeAt(GlobalPosition3D) const;
 	[[nodiscard]] virtual Link::Ptr intersectRayLinks(const Ray<GlobalPosition3D> &) const = 0;
 	[[nodiscard]] virtual Node::Ptr intersectRayNodes(const Ray<GlobalPosition3D> &) const;
 
-	[[nodiscard]] Link::Nexts routeFromTo(const Link::End &, Position3D) const;
+	[[nodiscard]] Link::Nexts routeFromTo(const Link::End &, GlobalPosition3D) const;
 	[[nodiscard]] Link::Nexts routeFromTo(const Link::End &, const Node::Ptr &) const;
 
-	virtual Link::CCollection candidateStraight(Position3D, Position3D) = 0;
-	virtual Link::CCollection candidateJoins(Position3D, Position3D) = 0;
-	virtual Link::CCollection candidateExtend(Position3D, Position3D) = 0;
-	virtual Link::CCollection addStraight(Position3D, Position3D) = 0;
-	virtual Link::CCollection addJoins(Position3D, Position3D) = 0;
-	virtual Link::CCollection addExtend(Position3D, Position3D) = 0;
+	virtual Link::CCollection candidateStraight(GlobalPosition3D, GlobalPosition3D) = 0;
+	virtual Link::CCollection candidateJoins(GlobalPosition3D, GlobalPosition3D) = 0;
+	virtual Link::CCollection candidateExtend(GlobalPosition3D, GlobalPosition3D) = 0;
+	virtual Link::CCollection addStraight(GlobalPosition3D, GlobalPosition3D) = 0;
+	virtual Link::CCollection addJoins(GlobalPosition3D, GlobalPosition3D) = 0;
+	virtual Link::CCollection addExtend(GlobalPosition3D, GlobalPosition3D) = 0;
 
 	[[nodiscard]] virtual float findNodeDirection(Node::AnyCPtr) const = 0;
 
 protected:
 	static void joinLinks(const Link::Ptr & l, const Link::Ptr & ol);
-	static GenCurveDef genCurveDef(const Position3D & start, const Position3D & end, float startDir);
+	static GenCurveDef genCurveDef(const GlobalPosition3D & start, const GlobalPosition3D & end, float startDir);
 	static std::pair<GenCurveDef, GenCurveDef> genCurveDef(
-			const Position3D & start, const Position3D & end, float startDir, float endDir);
+			const GlobalPosition3D & start, const GlobalPosition3D & end, float startDir, float endDir);
 
 	using Nodes = std::set<Node::Ptr, PtrMemberSorter<Node::Ptr, &Node::pos>>;
 	Nodes nodes;
@@ -71,7 +71,7 @@ protected:
 public:
 	template<typename L, typename... Params>
 	std::shared_ptr<L>
-	candidateLink(Position3D a, Position3D b, Params &&... params)
+	candidateLink(GlobalPosition3D a, GlobalPosition3D b, Params &&... params)
 		requires std::is_base_of_v<T, L>
 	{
 		const auto node1 = candidateNodeAt(a).first, node2 = candidateNodeAt(b).first;
@@ -80,7 +80,7 @@ public:
 
 	template<typename L, typename... Params>
 	std::shared_ptr<L>
-	addLink(Position3D a, Position3D b, Params &&... params)
+	addLink(GlobalPosition3D a, GlobalPosition3D b, Params &&... params)
 		requires std::is_base_of_v<T, L>
 	{
 		const auto node1 = nodeAt(a), node2 = nodeAt(b);
@@ -89,12 +89,12 @@ public:
 		return l;
 	}
 
-	Link::CCollection candidateStraight(Position3D n1, Position3D n2) override;
-	Link::CCollection candidateJoins(Position3D, Position3D) override;
-	Link::CCollection candidateExtend(Position3D, Position3D) override;
-	Link::CCollection addStraight(Position3D n1, Position3D n2) override;
-	Link::CCollection addJoins(Position3D, Position3D) override;
-	Link::CCollection addExtend(Position3D, Position3D) override;
+	Link::CCollection candidateStraight(GlobalPosition3D n1, GlobalPosition3D n2) override;
+	Link::CCollection candidateJoins(GlobalPosition3D, GlobalPosition3D) override;
+	Link::CCollection candidateExtend(GlobalPosition3D, GlobalPosition3D) override;
+	Link::CCollection addStraight(GlobalPosition3D n1, GlobalPosition3D n2) override;
+	Link::CCollection addJoins(GlobalPosition3D, GlobalPosition3D) override;
+	Link::CCollection addExtend(GlobalPosition3D, GlobalPosition3D) override;
 
 	[[nodiscard]] float findNodeDirection(Node::AnyCPtr) const override;
 
diff --git a/game/network/network.impl.h b/game/network/network.impl.h
index 4acbb6d..f9595ed 100644
--- a/game/network/network.impl.h
+++ b/game/network/network.impl.h
@@ -54,16 +54,16 @@ NetworkOf<T>::findNodeDirection(Node::AnyCPtr n) const
 
 template<typename T>
 Link::CCollection
-NetworkOf<T>::candidateStraight(Position3D n1, Position3D n2)
+NetworkOf<T>::candidateStraight(GlobalPosition3D n1, GlobalPosition3D n2)
 {
 	return {candidateLink<typename T::StraightLink>(n1, n2)};
 }
 
 template<typename T>
 Link::CCollection
-NetworkOf<T>::candidateJoins(Position3D start, Position3D end)
+NetworkOf<T>::candidateJoins(GlobalPosition3D start, GlobalPosition3D end)
 {
-	if (glm::distance(start, end) < 2.F) {
+	if (glm::length(RelativePosition3D(start - end)) < 2000.F) {
 		return {};
 	}
 	const auto defs = genCurveDef(
@@ -75,7 +75,7 @@ NetworkOf<T>::candidateJoins(Position3D start, Position3D end)
 
 template<typename T>
 Link::CCollection
-NetworkOf<T>::candidateExtend(Position3D start, Position3D end)
+NetworkOf<T>::candidateExtend(GlobalPosition3D start, GlobalPosition3D end)
 {
 	const auto [cstart, cend, centre] = genCurveDef(start, end, findNodeDirection(candidateNodeAt(start).first));
 	return {candidateLink<typename T::CurveLink>(cstart, cend, centre)};
@@ -83,16 +83,16 @@ NetworkOf<T>::candidateExtend(Position3D start, Position3D end)
 
 template<typename T>
 Link::CCollection
-NetworkOf<T>::addStraight(Position3D n1, Position3D n2)
+NetworkOf<T>::addStraight(GlobalPosition3D n1, GlobalPosition3D n2)
 {
 	return {addLink<typename T::StraightLink>(n1, n2)};
 }
 
 template<typename T>
 Link::CCollection
-NetworkOf<T>::addJoins(Position3D start, Position3D end)
+NetworkOf<T>::addJoins(GlobalPosition3D start, GlobalPosition3D end)
 {
-	if (glm::distance(start, end) < 2.F) {
+	if (glm::length(RelativePosition3D(start - end)) < 2000.F) {
 		return {};
 	}
 	const auto defs = genCurveDef(start, end, findNodeDirection(nodeAt(start)), findNodeDirection(nodeAt(end)));
@@ -103,7 +103,7 @@ NetworkOf<T>::addJoins(Position3D start, Position3D end)
 
 template<typename T>
 Link::CCollection
-NetworkOf<T>::addExtend(Position3D start, Position3D end)
+NetworkOf<T>::addExtend(GlobalPosition3D start, GlobalPosition3D end)
 {
 	const auto [cstart, cend, centre] = genCurveDef(start, end, findNodeDirection(nodeAt(start)));
 	return {addLink<typename T::CurveLink>(cstart, cend, centre)};
diff --git a/game/network/rail.cpp b/game/network/rail.cpp
index 303f1c8..79aaf97 100644
--- a/game/network/rail.cpp
+++ b/game/network/rail.cpp
@@ -9,9 +9,7 @@
 #include <gfx/models/vertex.h>
 #include <glad/gl.h>
 #include <glm/gtx/transform.hpp>
-#include <initializer_list>
 #include <maths.h>
-#include <stdexcept>
 #include <utility>
 #include <vector>
 
@@ -28,7 +26,7 @@ RailLinks::tick(TickDuration)
 }
 
 std::shared_ptr<RailLink>
-RailLinks::addLinksBetween(Position3D start, Position3D end)
+RailLinks::addLinksBetween(GlobalPosition3D start, GlobalPosition3D end)
 {
 	auto node1ins = newNodeAt(start), node2ins = newNodeAt(end);
 	if (node1ins.second == NodeIs::NotInNetwork && node2ins.second == NodeIs::NotInNetwork) {
@@ -41,31 +39,32 @@ RailLinks::addLinksBetween(Position3D start, Position3D end)
 		std::swap(start, end);
 	}
 	// Find start link/end - opposite entry dir to existing link; so pi +...
-	const float dir = pi + findNodeDirection(node1ins.first);
+	const Angle dir = pi + findNodeDirection(node1ins.first);
 	if (dir == vector_yaw(end - start)) {
 		return addLink<RailLinkStraight>(start, end);
 	}
-	const Position2D flatStart {start.xy()}, flatEnd {end.xy()};
+	const auto flatStart {start.xy()}, flatEnd {end.xy()};
 	if (node2ins.second == NodeIs::InNetwork) {
 		auto midheight = [&](auto mid) {
-			const auto sm = glm::distance(flatStart, mid), em = glm::distance(flatEnd, mid);
-			return start.z + ((end.z - start.z) * (sm / (sm + em)));
+			const auto sm = glm::length(RelativePosition2D(flatStart - mid)),
+					   em = glm::length(RelativePosition2D(flatEnd - mid));
+			return start.z + GlobalDistance(RelativeDistance(end.z - start.z) * (sm / (sm + em)));
 		};
 		const float dir2 = pi + findNodeDirection(node2ins.first);
 		if (const auto radii = find_arcs_radius(flatStart, dir, flatEnd, dir2); radii.first < radii.second) {
 			const auto radius {radii.first};
-			const auto c1 = flatStart + sincosf(dir + half_pi) * radius;
-			const auto c2 = flatEnd + sincosf(dir2 + half_pi) * radius;
-			const auto mid = (c1 + c2) / 2.F;
+			const auto c1 = flatStart + GlobalPosition2D(sincosf(dir + half_pi) * radius);
+			const auto c2 = flatEnd + GlobalPosition2D(sincosf(dir2 + half_pi) * radius);
+			const auto mid = (c1 + c2) / 2;
 			const auto midh = mid || midheight(mid);
 			addLink<RailLinkCurve>(start, midh, c1);
 			return addLink<RailLinkCurve>(end, midh, c2);
 		}
 		else {
 			const auto radius {radii.second};
-			const auto c1 = flatStart + sincosf(dir - half_pi) * radius;
-			const auto c2 = flatEnd + sincosf(dir2 - half_pi) * radius;
-			const auto mid = (c1 + c2) / 2.F;
+			const auto c1 = flatStart + GlobalPosition2D(sincosf(dir - half_pi) * radius);
+			const auto c2 = flatEnd + GlobalPosition2D(sincosf(dir2 - half_pi) * radius);
+			const auto mid = (c1 + c2) / 2;
 			const auto midh = mid || midheight(mid);
 			addLink<RailLinkCurve>(midh, start, c1);
 			return addLink<RailLinkCurve>(midh, end, c2);
@@ -100,7 +99,7 @@ RailLink::render(const SceneShader &) const
 	mesh->Draw();
 }
 
-constexpr const std::array<std::pair<Position3D, float>, RAIL_CROSSSECTION_VERTICES> railCrossSection {{
+constexpr const std::array<std::pair<RelativePosition3D, float>, RAIL_CROSSSECTION_VERTICES> railCrossSection {{
 		//   ___________
 		// _/           \_
 		//  left to right
@@ -122,59 +121,57 @@ RailLinkStraight::RailLinkStraight(const Node::Ptr & a, const Node::Ptr & b) : R
 {
 }
 
-RailLinkStraight::RailLinkStraight(Node::Ptr a, Node::Ptr b, const Position3D & diff) :
+RailLinkStraight::RailLinkStraight(Node::Ptr a, Node::Ptr b, const RelativePosition3D & diff) :
 	Link({std::move(a), vector_yaw(diff)}, {std::move(b), vector_yaw(-diff)}, glm::length(diff))
 {
 	if (glGenVertexArrays) {
 		std::vector<Vertex> vertices;
 		vertices.reserve(2 * railCrossSection.size());
 		const auto len = round_sleepers(length / 2000.F);
-		const auto e {flat_orientation(diff)};
+		const glm::mat3 trans {flat_orientation(diff)};
 		for (auto ei : {1U, 0U}) {
-			const auto trans {glm::translate(ends[ei].node->pos) * e};
 			for (const auto & rcs : railCrossSection) {
-				const Position3D m {(trans * (rcs.first || 1.F))};
-				vertices.emplace_back(m, Position2D {rcs.second, len * static_cast<float>(ei)}, up);
+				const auto m {ends[ei].node->pos + GlobalPosition3D(trans * rcs.first)};
+				vertices.emplace_back(m, TextureRelCoord {rcs.second, len * static_cast<float>(ei)}, up);
 			}
 		}
 		mesh = defaultMesh(vertices);
 	}
 }
 
-RailLinkCurve::RailLinkCurve(const Node::Ptr & a, const Node::Ptr & b, Position2D c) :
-	RailLinkCurve(a, b, c || a->pos.z, {c || 0.F, a->pos, b->pos})
+RailLinkCurve::RailLinkCurve(const Node::Ptr & a, const Node::Ptr & b, GlobalPosition2D c) :
+	RailLinkCurve(a, b, c || a->pos.z, {c || 0, a->pos, b->pos})
 {
 }
 
-RailLinkCurve::RailLinkCurve(const Node::Ptr & a, const Node::Ptr & b, Position3D c, const Arc arc) :
+RailLinkCurve::RailLinkCurve(const Node::Ptr & a, const Node::Ptr & b, GlobalPosition3D c, const Arc arc) :
 	Link({a, normalize(arc.first + half_pi)}, {b, normalize(arc.second - half_pi)},
-			(glm::length(a->pos - c)) * arc_length(arc)),
-	LinkCurve {c, glm::length(ends[0].node->pos - c), arc}
+			glm::length(RelativePosition3D(a->pos - c)) * arc_length(arc)),
+	LinkCurve {c, glm::length(RelativePosition3D(ends[0].node->pos - c)), arc}
 {
 	if (glGenVertexArrays) {
 		const auto & e0p {ends[0].node->pos};
 		const auto & e1p {ends[1].node->pos};
 		const auto slength = round_sleepers(length / 2.F);
 		const auto segs = std::round(slength / std::pow(radius, 0.7F));
-		const auto step {Position3D {arc_length(arc), e1p.z - e0p.z, slength / 1000.F} / segs};
-		const auto trans {glm::translate(centreBase)};
+		const auto step {RelativePosition3D {arc_length(arc), e1p.z - e0p.z, slength / 1000.F} / segs};
 
 		auto segCount = static_cast<std::size_t>(std::lround(segs)) + 1;
 		std::vector<Vertex> vertices;
 		vertices.reserve(segCount * railCrossSection.size());
-		for (Position3D swing = {arc.first, centreBase.z - e0p.z, 0.F}; segCount; swing += step, --segCount) {
+		for (RelativePosition3D swing = {arc.first, centreBase.z - e0p.z, 0.F}; segCount; swing += step, --segCount) {
 			const auto t {
-					trans * glm::rotate(half_pi - swing.x, up) * glm::translate(Position3D {radius, 0.F, swing.y})};
+					glm::rotate(half_pi - swing.x, up) * glm::translate(RelativePosition3D {radius, 0.F, swing.y})};
 			for (const auto & rcs : railCrossSection) {
-				const Position3D m {(t * (rcs.first || 1.F))};
-				vertices.emplace_back(m, Position2D {rcs.second, swing.z}, up);
+				const auto m {centreBase + GlobalPosition3D(t * (rcs.first || 1.F))};
+				vertices.emplace_back(m, TextureRelCoord {rcs.second, swing.z}, up);
 			}
 		}
 		mesh = defaultMesh(vertices);
 	}
 }
 
-Position3D
+RelativePosition3D
 RailLink::vehiclePositionOffset() const
 {
 	return RAIL_HEIGHT;
diff --git a/game/network/rail.h b/game/network/rail.h
index 4a1932f..986b0aa 100644
--- a/game/network/rail.h
+++ b/game/network/rail.h
@@ -32,7 +32,7 @@ public:
 	NO_MOVE(RailLink);
 
 protected:
-	[[nodiscard]] Position3D vehiclePositionOffset() const override;
+	[[nodiscard]] RelativePosition3D vehiclePositionOffset() const override;
 	[[nodiscard]] static Mesh::Ptr defaultMesh(const std::span<Vertex> vertices);
 
 	Mesh::Ptr mesh;
@@ -45,22 +45,22 @@ public:
 	RailLinkStraight(const Node::Ptr &, const Node::Ptr &);
 
 private:
-	RailLinkStraight(Node::Ptr, Node::Ptr, const Position3D & diff);
+	RailLinkStraight(Node::Ptr, Node::Ptr, const RelativePosition3D & diff);
 };
 
 class RailLinkCurve : public RailLink, public LinkCurve {
 public:
-	RailLinkCurve(const Node::Ptr &, const Node::Ptr &, Position2D);
+	RailLinkCurve(const Node::Ptr &, const Node::Ptr &, GlobalPosition2D);
 
 private:
-	RailLinkCurve(const Node::Ptr &, const Node::Ptr &, Position3D, const Arc);
+	RailLinkCurve(const Node::Ptr &, const Node::Ptr &, GlobalPosition3D, const Arc);
 };
 
 class RailLinks : public NetworkOf<RailLink>, public WorldObject {
 public:
 	RailLinks();
 
-	std::shared_ptr<RailLink> addLinksBetween(Position3D start, Position3D end);
+	std::shared_ptr<RailLink> addLinksBetween(GlobalPosition3D start, GlobalPosition3D end);
 
 private:
 	void tick(TickDuration elapsed) override;