gofrettin / nvmeditor

A try at a navmesh editor for Silkroad Online

"#A try at a navmesh editor for Silkroad Online"

In order to read and write Silkroad Online (hereafter named SRO), it was required to reverse engineer the binary structure of the .nvm files.

A Navmesh file consists of different parts:

#Navmesh Metadata

The navmesh metadata contains information about how many entries of each element exists inside of the navmesh.

The structure of metadata is the following:

struct NavMeshMetadata 
{
	char header[12]; // 12 bytes
	ushort nav_entries;
	uint cell_entries;
	uint cell_extra_entries;
	uint region_link_entries;
	uint cell_link_entries;

};

As we can see, there is a header (a string of 12 chars) and the number of entries for each type.

#Navigation Entry A navigation entry contains the position, as a vector, of the spot a yaw value that indicates the orientation of the box. It also contains a collision flag, an unique_id and some other information pertaining to the way that SRO maps are defined.

The structure is the following:

struct NavigationEntry {
	uint id;
	Vector3 position;
	ushort collision;
	float yaw;
	ushort unique_id;
	ushort unknown_0;
	ushort event_zone; // 0 = no collision while using CTF suit, 255 = collision when using CTF suit
	ushort region_id;
	ushort mount_point_entries;
	std::vector<MountPoint> mount_points;
}

Other structures can be found below:

struct MountPoint{
	BYTE mount_point[6];
}

struct NavigationCell {
	Vector2 min;
	Vector2 max;
	BYTE entry_count;
	std::vector<ushort> entry_index;
}

struct RegionLink {
	Vector2 min;
	Vector2 max;
	BYTE line_flag;
	BYTE line_source;
	BYTE line_destination;
	ushort source_cell;
	ushort destination_cell;
	ushort source_region;
	ushort destination_region;
}

struct NavigationCellLink {
	Vector2 min;
	Vector2 max;

	BYTE line_flag;
	BYTE line_source;
	BYTE line_destination;

	ushort source_cell;
	ushort destination_cell;
}

struct TextureMap {
	
	ushort w1;
	ushort w2;
	ushort w3;
	ushort w4;
};

struct HeightMap {
	float Height;
};

And finally the navmesh struct:

struct NavMesh {
	NavMeshMetadata metadata;//std::unique_ptr<NavMeshMetadata> metadata;
	std::map<uint, NavigationEntry> nav_entries;
	std::vector<NavigationCell> nav_cells;
	std::vector<RegionLink> region_links;
	std::vector<NavigationCellLink> nav_cell_links;
	std::vector<TextureMap> texture_maps;
	std::vector<HeightMap> height_maps;
};