Region Loader¶

Loads regions on demand and keeps track of which ones are in memory.

Ground colours blend across region boundaries, so a region is never useful on its own - see TRegionLoader.LoadRegionAndNeighbors.

RegionLoader.BuildLookup¶

procedure TRegionLoader.BuildLookup();

Builds the table that turns a region coordinate into an index into Regions.

It is a flat 256 by 256 array of indices rather than a search, since region coordinates are bounded and small, and -1 marks a coordinate with no region loaded. Already-built tables are left alone; TRegionLoader.LoadRegionAndNeighbors keeps it up to date as it goes.

RegionLoader.RegionCoordinateIndex¶

function TRegionLoader.RegionCoordinateIndex(x, y: Integer): Integer;

The index in Regions of the region at region coordinates x, y, or -1 if it is not loaded.

RegionLoader.RegionFileData¶

function TRegionLoader.RegionFileData(id, fileID: Integer; out data: TByteArray): Boolean; static;

The bytes of one file of region id’s map archive - file 0 is its terrain and file 1 its objects - or False if the map index holds no such archive or file.

Both are looked up by index rather than through Value, so a region that is simply empty world - which most region ids are - costs one probe of each table and no copying at all.

The map index has to be cached first.

RegionLoader.LoadMapDef¶

function TRegionLoader.LoadMapDef(id: Integer; out map: TMapDefinition): Boolean;

Decodes the terrain of region id, returning False if the map index holds nothing for it - which is the normal case for the many region ids that are simply empty world.

The map index has to be cached first.

RegionLoader.LoadLocDef¶

function TRegionLoader.LoadLocDef(id: Integer; out locs: TLocationsDefinition): Boolean;

Decodes the object placements of region id, returning False if it has none.

A region that has terrain need not have objects, which is why this is separate from TRegionLoader.LoadMapDef.

RegionLoader.LoadRegion¶

function TRegionLoader.LoadRegion(id: Integer; out region: TRegion): Boolean;

Builds one region from the cache: its terrain, and its objects if it has any. Returns False if there is no such region.

RegionLoader.LoadRegionAt¶

function TRegionLoader.LoadRegionAt(regionX, regionY: Integer): Integer;

The index in Regions of the region at regionX, regionY, loading it first if it is not loaded yet. Returns -1 if there is no such region.

RegionLoader.LoadRegionAndNeighbors¶

function TRegionLoader.LoadRegionAndNeighbors(regionX, regionY: Integer): Boolean;

Loads the region at regionX, regionY along with the four next to it, and returns whether the middle one exists.

The neighbours are needed because ground colours blend across region boundaries - without them the map would show a seam at every edge. Regions already loaded are left alone, so calling this per chunk while panning around only pays for what is new.

RegionLoader.LoadAllRegions¶

procedure TRegionLoader.LoadAllRegions();

Loads every region the cache has, reporting progress as it goes.

This is minutes of work and gigabytes of memory - it is for dumping the whole world, not for rendering part of it. TRegionLoader.LoadRegionAndNeighbors is what a map viewer wants.