Holy hell, finally got this working with an R9 390 + Ubuntu.

include/map/ArrayMap.h

@@ -20,7 +20,7 @@ public:
 	// =========== DEBUG =========== //
 	char* getDataPtr();
 	
-	std::vector<std::tuple<sf::Vector3i, char>>  ArrayMap::CastRayCharArray(
+	std::vector<std::tuple<sf::Vector3i, char>>  CastRayCharArray(
 		char* map,
 		sf::Vector3i* map_dim,
 		sf::Vector2f* cam_dir,
@@ -32,4 +32,4 @@ private:
 	char *voxel_data;
 	sf::Vector3i dimensions;
 	
-};
+};