From 538af692b66e67dfa4f347cc9ddd784a36f9a991 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Sat, 20 Jan 2024 01:23:53 +0000
Subject: Update network with vertex array

---
 game/network/network.h |  5 ++++-
 game/network/rail.cpp  | 37 +++++++++++++++++++++++++++++--------
 game/network/rail.h    |  3 +++
 test/test-network.cpp  |  2 ++
 4 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/game/network/network.h b/game/network/network.h
index 49322f9..5725360 100644
--- a/game/network/network.h
+++ b/game/network/network.h
@@ -60,8 +60,11 @@ protected:
 };
 
 template<typename LinkType> class NetworkLinkHolder {
-protected:
+public:
+	// Implemented per LinkType to configure vao
+	NetworkLinkHolder();
 	friend LinkType;
+	glVertexArray vao;
 	mutable InstanceVertices<typename LinkType::Vertex> vertices;
 };
 
diff --git a/game/network/rail.cpp b/game/network/rail.cpp
index 9766851..efe4e2d 100644
--- a/game/network/rail.cpp
+++ b/game/network/rail.cpp
@@ -186,20 +186,41 @@ RailLink::vehiclePositionOffset() const
 	return RAIL_HEIGHT;
 }
 
-void
-RailLinks::render(const SceneShader & shader) const
+template<> NetworkLinkHolder<RailLinkStraight>::NetworkLinkHolder()
+{
+	VertexArrayObject {vao}
+			.addAttribs<RailLinkStraight::Vertex, &RailLinkStraight::Vertex::a, &RailLinkStraight::Vertex::b,
+					&RailLinkStraight::Vertex::rotation, &RailLinkStraight::Vertex::textureRepeats>(
+					vertices.bufferName());
+}
+
+template<> NetworkLinkHolder<RailLinkCurve>::NetworkLinkHolder()
 {
-	auto renderType = [](auto & v, auto & s) {
-		if (auto count = v.size()) {
+	VertexArrayObject {vao}
+			.addAttribs<RailLinkCurve::Vertex, &RailLinkCurve::Vertex::a, &RailLinkCurve::Vertex::b,
+					&RailLinkCurve::Vertex::c, &RailLinkCurve::Vertex::textureRepeats>(vertices.bufferName());
+}
+
+namespace {
+	template<typename LinkType>
+	void
+	renderType(const NetworkLinkHolder<LinkType> & n, auto & s)
+	{
+		if (auto count = n.vertices.size()) {
 			s.use();
-			glBindBuffer(GL_VERTEX_ARRAY, v.bufferName());
+			glBindVertexArray(n.vao);
 			glDrawArrays(GL_POINTS, 0, static_cast<GLsizei>(count));
 		}
 	};
+}
+
+void
+RailLinks::render(const SceneShader & shader) const
+{
 	if (!links.objects.empty()) {
 		texture->bind();
-		renderType(NetworkLinkHolder<RailLinkStraight>::vertices, shader.networkStraight);
-		renderType(NetworkLinkHolder<RailLinkCurve>::vertices, shader.networkCurve);
-		glBindBuffer(GL_VERTEX_ARRAY, 0);
+		renderType<RailLinkStraight>(*this, shader.networkStraight);
+		renderType<RailLinkCurve>(*this, shader.networkCurve);
+		glBindVertexArray(0);
 	}
 }
diff --git a/game/network/rail.h b/game/network/rail.h
index 5191b90..b6a9ebe 100644
--- a/game/network/rail.h
+++ b/game/network/rail.h
@@ -72,6 +72,9 @@ private:
 	InstanceVertices<Vertex>::InstanceProxy instance;
 };
 
+template<> NetworkLinkHolder<RailLinkStraight>::NetworkLinkHolder();
+template<> NetworkLinkHolder<RailLinkCurve>::NetworkLinkHolder();
+
 class RailLinks : public NetworkOf<RailLink, RailLinkStraight, RailLinkCurve>, public WorldObject {
 public:
 	RailLinks();
diff --git a/test/test-network.cpp b/test/test-network.cpp
index df61b94..174e2a5 100644
--- a/test/test-network.cpp
+++ b/test/test-network.cpp
@@ -52,6 +52,8 @@ struct TestLinkS : public TestLink, public LinkStraight {
 constexpr GlobalPosition3D p000 {0, 0, 0}, p100 {10000, 0, 0}, p200 {20000, 0, 0}, p300 {30000, 0, 0};
 constexpr GlobalPosition3D p110 {10000, 10000, 0};
 
+template<> NetworkLinkHolder<TestLinkS>::NetworkLinkHolder() = default;
+
 struct TestNetwork : public NetworkOf<TestLink, TestLinkS> {
 	TestNetwork() : NetworkOf<TestLink, TestLinkS> {RESDIR "rails.jpg"}
 	{
-- 
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