Mesh split, bogeys follow rails.

Wow. This commit is too big. It:

* splits obj loaded meshes into individual named objects.
* moves obj to mesh(es) code into new file obj.impl.cpp, removing the
  clutter from mesh
* removes Physical for providing the wrong level of abstraction
* bit of a hack to adjust loaded models to offset rail vehicle bogeys to
  0 centre, and then applies their calculated position to the mesh

All in all, quite a lot of mess... But the result is the rail vehicle
bogeys now follow the rails quite authentically.

1 files changed, 13 insertions, 0 deletions

diff --git a/game/vehicles/railloco.h b/game/vehicles/railloco.h
index ce4012a..0d0425a 100644
--- a/game/vehicles/railloco.h
+++ b/game/vehicles/railloco.h
@@ -1,15 +1,28 @@
 #include "game/network/link.h"
 #include "game/vehicles/vehicle.h"
 #include "game/worldobject.h"
+#include "gfx/models/mesh.h"
 #include <memory>
 #include <string>
 #include <vector>
 
+class Texture;
 class RailVehicle : public Vehicle {
 public:
+	struct Bogey {
+		Transform location;
+		MeshPtr mesh;
+	};
+
 	using Vehicle::Vehicle;
+	void render(const Shader & shader) const override;
+
+	std::array<Bogey, 2> bogeys;
+	MeshPtr bodyMesh;
+	std::shared_ptr<Texture> texture;
 	float wheelBase;
 	float length;
+
 	friend class RailLoco;
 };