Initial commit of the route finder

6 files changed, 235 insertions, 0 deletions

diff --git a/game/network/network.cpp b/game/network/network.cpp
index fd61764..7349ff0 100644
--- a/game/network/network.cpp
+++ b/game/network/network.cpp
@@ -1,9 +1,11 @@
 #include "network.h"
+#include "routeWalker.h"
 #include <array>
 #include <cache.h>
 #include <game/network/link.h>
 #include <gfx/models/texture.h>
 #include <initializer_list>
+#include <stdexcept>
 #include <utility>
 
 Network::Network(const std::string & tn) : texture {Texture::cachedTexture.get(tn)} { }
@@ -44,3 +46,19 @@ Network::joinLinks(const LinkPtr & l, const LinkPtr & ol)
 		}
 	}
 }
+
+std::vector<LinkWPtr>
+Network::routeFromTo(const Link::End & start, glm::vec3 dest) const
+{
+	auto destNode {findNodeAt(dest)};
+	if (!destNode) {
+		throw std::out_of_range("Node does not exist in network");
+	}
+	return routeFromTo(start, destNode);
+}
+
+std::vector<LinkWPtr>
+Network::routeFromTo(const Link::End & end, const NodePtr & dest) const
+{
+	return RouteWalker().findRouteTo(end, dest);
+}
diff --git a/game/network/network.h b/game/network/network.h
index c6d4dfa..f84c90c 100644
--- a/game/network/network.h
+++ b/game/network/network.h
@@ -10,6 +10,7 @@
 #include <sorting.hpp>
 #include <string>
 #include <utility>
+#include <vector>
 
 class Texture;
 class Shader;
@@ -22,6 +23,9 @@ public:
 	[[nodiscard]] NodePtr nodeAt(glm::vec3);
 	[[nodiscard]] std::pair<NodePtr, bool> newNodeAt(glm::vec3);
 
+	[[nodiscard]] std::vector<LinkWPtr> routeFromTo(const Link::End &, glm::vec3) const;
+	[[nodiscard]] std::vector<LinkWPtr> routeFromTo(const Link::End &, const NodePtr &) const;
+
 protected:
 	static void joinLinks(const LinkPtr & l, const LinkPtr & ol);
 
diff --git a/game/network/routeWalker.cpp b/game/network/routeWalker.cpp
new file mode 100644
index 0000000..496f9f3
--- /dev/null
+++ b/game/network/routeWalker.cpp
@@ -0,0 +1,37 @@
+#include "routeWalker.h"
+#include <array>
+#include <game/network/link.h>
+#include <limits>
+#include <memory>
+#include <utility>
+
+RouteWalker::RouteWalker() : solutionLength {std::numeric_limits<float>::max()} { }
+
+RouteWalker::Solution
+RouteWalker::findRouteTo(const Link::End & currentEnd, const NodePtr & dest)
+{
+	findRouteTo(currentEnd, dest, 0);
+	return bestSolution;
+}
+
+void
+// NOLINTNEXTLINE(misc-no-recursion)
+RouteWalker::findRouteTo(const Link::End & currentEnd, const NodePtr & dest, float length)
+{
+	if (currentEnd.node == dest && length < solutionLength) {
+		bestSolution = currentSolution;
+		solutionLength = length;
+		return;
+	}
+	if (visited.contains(&currentEnd)) { // We've been here before
+		return;
+	}
+	visited.insert(&currentEnd);
+	for (const auto & nexts : currentEnd.nexts) {
+		const auto link = nexts.first.lock();
+		currentSolution.push_back(link);
+		findRouteTo(link->ends[!nexts.second], dest, length + link->length);
+		currentSolution.pop_back();
+	}
+	visited.erase(&currentEnd);
+}
diff --git a/game/network/routeWalker.h b/game/network/routeWalker.h
new file mode 100644
index 0000000..7b1e1c8
--- /dev/null
+++ b/game/network/routeWalker.h
@@ -0,0 +1,24 @@
+#ifndef ROUTEWALKER_H
+#define ROUTEWALKER_H
+
+#include "link.h"
+#include <set>
+#include <vector>
+
+class RouteWalker {
+public:
+	using Solution = std::vector<LinkWPtr>;
+
+	RouteWalker();
+
+	Solution findRouteTo(const Link::End & currentEnd, const NodePtr & dest);
+
+private:
+	void findRouteTo(const Link::End & currentEnd, const NodePtr & dest, float length);
+
+	std::set<const Link::End *> visited;
+	Solution bestSolution, currentSolution;
+	float solutionLength;
+};
+
+#endif
diff --git a/test/Jamfile.jam b/test/Jamfile.jam
index ffc1a19..f1fda72 100644
--- a/test/Jamfile.jam
+++ b/test/Jamfile.jam
@@ -17,3 +17,4 @@ project : requirements
 run test-collection.cpp ;
 run test-obj.cpp ;
 run test-maths.cpp ;
+run test-network.cpp ;
diff --git a/test/test-network.cpp b/test/test-network.cpp
new file mode 100644
index 0000000..80ff1ef
--- /dev/null
+++ b/test/test-network.cpp
@@ -0,0 +1,151 @@
+#define BOOST_TEST_MODULE network
+
+#include <boost/test/data/test_case.hpp>
+#include <boost/test/unit_test.hpp>
+
+#include <array>
+#include <collection.hpp>
+#include <game/network/link.h>
+#include <game/network/network.h>
+#include <game/network/network.impl.h> // IWYU pragma: keep
+#include <glm/glm.hpp>
+#include <location.hpp>
+#include <maths.h>
+#include <memory>
+#include <stdexcept>
+#include <stream_support.hpp>
+#include <utility>
+#include <vector>
+
+struct TestLink : public Link {
+	TestLink(NodePtr a, NodePtr b, float ad, float bd, float l) : Link {{std::move(a), ad}, {std::move(b), bd}, l} { }
+	[[nodiscard]] Location
+	positionAt(float, unsigned char) const override
+	{
+		throw std::runtime_error("not implemented");
+	}
+};
+
+constexpr glm::vec3 p000 {0, 0, 0}, p100 {1, 0, 0}, p200 {2, 0, 0}, p300 {3, 0, 0};
+
+struct TestNetwork : public NetworkOf<TestLink> {
+	TestNetwork() : NetworkOf<TestLink> {RESDIR "rails.jpg"}
+	{
+		//       0        1        2
+		// p000 <-> p100 <-> p200 <-> p300
+		addLink<TestLink>(p000, p100, 0.F, pi, 1.F);
+		addLink<TestLink>(p100, p200, 0.F, pi, 1.F);
+		addLink<TestLink>(p200, p300, 0.F, pi, 1.F);
+	}
+};
+
+const auto VALID_NODES = boost::unit_test::data::make<glm::vec3>({
+		p000,
+		p100,
+		p200,
+		p300,
+});
+const auto INVALID_NODES = boost::unit_test::data::make<glm::vec3>({
+		{1000, 0, 0},
+		{0, 1000, 0},
+		{0, 0, 1000},
+});
+
+BOOST_FIXTURE_TEST_SUITE(tn, TestNetwork)
+
+BOOST_DATA_TEST_CASE(findNodeAt_valid, VALID_NODES, p)
+{
+	auto n = findNodeAt(p);
+	BOOST_REQUIRE(n);
+	BOOST_CHECK_EQUAL(n->pos, p);
+}
+
+BOOST_DATA_TEST_CASE(findNodeAt_invalid, INVALID_NODES, p)
+{
+	BOOST_REQUIRE(!findNodeAt(p));
+}
+
+BOOST_DATA_TEST_CASE(nodeAt, VALID_NODES + INVALID_NODES, p)
+{
+	auto n = nodeAt(p);
+	BOOST_REQUIRE(n);
+	BOOST_CHECK_EQUAL(n->pos, p);
+}
+
+BOOST_DATA_TEST_CASE(newNodeAt_existing, VALID_NODES, p)
+{
+	auto n = newNodeAt(p);
+	BOOST_CHECK(!n.second);
+	BOOST_REQUIRE(n.first);
+	BOOST_CHECK_EQUAL(n.first->pos, p);
+}
+
+BOOST_DATA_TEST_CASE(newNodeAt_new, INVALID_NODES, p)
+{
+	auto n = newNodeAt(p);
+	BOOST_CHECK(n.second);
+	BOOST_REQUIRE(n.first);
+	BOOST_CHECK_EQUAL(n.first->pos, p);
+}
+
+BOOST_AUTO_TEST_CASE(network_joins)
+{
+	// Ends
+	BOOST_CHECK(links.objects[0]->ends[0].nexts.empty());
+	BOOST_CHECK(links.objects[2]->ends[1].nexts.empty());
+	// Join 0 <-> 1
+	BOOST_REQUIRE_EQUAL(links.objects[0]->ends[1].nexts.size(), 1);
+	BOOST_CHECK_EQUAL(links.objects[0]->ends[1].nexts.front().first.lock().get(), links.objects[1].get());
+	BOOST_CHECK_EQUAL(links.objects[0]->ends[1].nexts.front().second, 0);
+	BOOST_REQUIRE_EQUAL(links.objects[1]->ends[0].nexts.size(), 1);
+	BOOST_CHECK_EQUAL(links.objects[1]->ends[0].nexts.front().first.lock().get(), links.objects[0].get());
+	BOOST_CHECK_EQUAL(links.objects[1]->ends[0].nexts.front().second, 1);
+	// Join 1 <-> 2
+	BOOST_REQUIRE_EQUAL(links.objects[1]->ends[1].nexts.size(), 1);
+	BOOST_CHECK_EQUAL(links.objects[1]->ends[1].nexts.front().first.lock().get(), links.objects[2].get());
+	BOOST_CHECK_EQUAL(links.objects[1]->ends[1].nexts.front().second, 0);
+	BOOST_REQUIRE_EQUAL(links.objects[2]->ends[0].nexts.size(), 1);
+	BOOST_CHECK_EQUAL(links.objects[2]->ends[0].nexts.front().first.lock().get(), links.objects[1].get());
+	BOOST_CHECK_EQUAL(links.objects[2]->ends[0].nexts.front().second, 1);
+}
+
+BOOST_DATA_TEST_CASE(routeTo_nodeNotInNetwork, INVALID_NODES, dest)
+{
+	const auto & start = links.objects.front()->ends[1];
+	BOOST_CHECK_THROW((void)routeFromTo(start, dest), std::out_of_range);
+}
+
+BOOST_AUTO_TEST_CASE(routeTo_noSteps)
+{
+	const auto & start = links.objects.front()->ends[1];
+	auto r = this->routeFromTo(start, p100);
+	BOOST_CHECK(r.empty());
+}
+
+BOOST_AUTO_TEST_CASE(routeTo_upStream_to2)
+{
+	const auto & start = links.objects.front()->ends[1];
+	auto r = this->routeFromTo(start, p200);
+	BOOST_REQUIRE_EQUAL(r.size(), 1);
+	BOOST_CHECK_EQUAL(r[0].lock().get(), links.objects[1].get());
+}
+
+BOOST_AUTO_TEST_CASE(routeTo_upStream_to3)
+{
+	const auto & start = links.objects.front()->ends[1];
+	auto r = this->routeFromTo(start, p300);
+	BOOST_REQUIRE_EQUAL(r.size(), 2);
+	BOOST_CHECK_EQUAL(r[0].lock().get(), links.objects[1].get());
+	BOOST_CHECK_EQUAL(r[1].lock().get(), links.objects[2].get());
+}
+
+BOOST_AUTO_TEST_CASE(routeTo_downStream_to0)
+{
+	const auto & start = links.objects.back()->ends[0];
+	auto r = this->routeFromTo(start, p000);
+	BOOST_REQUIRE_EQUAL(r.size(), 2);
+	BOOST_CHECK_EQUAL(r[0].lock().get(), links.objects[1].get());
+	BOOST_CHECK_EQUAL(r[1].lock().get(), links.objects[0].get());
+}
+
+BOOST_AUTO_TEST_SUITE_END()