From 2812584e271a62d8edd4d8ec683ea4c644730df2 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Mon, 15 Feb 2021 01:36:51 +0000
Subject: Basic support for rail wagons

---
 game/vehicles/railloco.cpp | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

(limited to 'game/vehicles/railloco.cpp')

diff --git a/game/vehicles/railloco.cpp b/game/vehicles/railloco.cpp
index a1add29..d61b882 100644
--- a/game/vehicles/railloco.cpp
+++ b/game/vehicles/railloco.cpp
@@ -39,10 +39,44 @@ RailLoco::tick(TickDuration dur)
 	const auto diff = glm::normalize(b2pos.GetPos() - b1pos.GetPos());
 	location.GetRot().x = -vector_pitch(diff);
 	location.GetRot().y = vector_yaw(diff);
+	updateWagons();
 }
 
+void
+RailLoco::updateWagons() const
+{
+	// Drag wagons
+	float trailBy {wheelBase + ((length - wheelBase)) / 2};
+	for (const auto & wagon : wagons) {
+		const auto w {wagon.lock()};
+		auto wTrailBy {trailBy + ((w->length - w->wheelBase) / 2)};
+		float b1linkDist {};
+		const auto b1Link = linkHist.getAt(wTrailBy - linkDist, &b1linkDist);
+		const auto b1Pos = b1Link.first->positionAt(b1linkDist, b1Link.second);
+		wTrailBy += w->wheelBase;
+		float b2linkDist {};
+		const auto b2Link = linkHist.getAt(wTrailBy - linkDist, &b2linkDist);
+		const auto b2Pos = b2Link.first->positionAt(b2linkDist, b2Link.second);
+		w->location.GetPos() = (b1Pos.GetPos() + b2Pos.GetPos()) / 2.F;
+		const auto diff = glm::normalize(b2Pos.GetPos() - b1Pos.GetPos());
+		w->location.GetRot().x = -vector_pitch(diff);
+		w->location.GetRot().y = vector_yaw(diff);
+		trailBy += w->length;
+	}
+}
+
+void RailWagon::tick(TickDuration) { }
+
 Brush47::Brush47(const LinkPtr & l) : RailLoco(l, "brush47.obj", "brush47.png")
 {
 	wheelBase = 15.7F;
+	length = 19.38F;
+	linkDist = wheelBase;
+}
+
+Brush47Wagon::Brush47Wagon(const LinkPtr & l) : RailWagon(l, "brush47.obj", "brush47.png")
+{
+	wheelBase = 15.7F;
+	length = 19.38F;
 	linkDist = wheelBase;
 }
-- 
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