Move Navmesh code away from dPhysics (#701)

dNavigation/dNavMesh.h

@@ -0,0 +1,38 @@
+#pragma once
+
+#include <cstdint>
+#include <vector>
+#include <map>
+#include <string>
+#include <cstring>
+
+#include "DetourExtensions.h"
+
+class NiPoint3;
+
+class dNavMesh {
+public:
+	dNavMesh(uint32_t zoneId);
+	~dNavMesh();
+
+	float GetHeightAtPoint(const NiPoint3& location);
+	std::vector<NiPoint3> GetPath(const NiPoint3& startPos, const NiPoint3& endPos, float speed = 10.0f);
+private:
+	void LoadNavmesh();
+
+	uint32_t m_ZoneId;
+
+	uint8_t* m_Triareas = nullptr;
+	rcHeightfield* m_Solid = nullptr;
+	rcCompactHeightfield* m_CHF = nullptr;
+	rcContourSet* m_CSet = nullptr;
+	rcPolyMesh* m_PMesh = nullptr;
+	rcConfig m_Config;
+	rcPolyMeshDetail* m_PMDMesh = nullptr;
+
+	class InputGeom* m_Geometry = nullptr;
+	class dtNavMesh* m_NavMesh = nullptr;
+	class dtNavMeshQuery* m_NavQuery = nullptr;
+	uint8_t m_NavMeshDrawFlags;
+	rcContext* m_Ctx = nullptr;
+};