Fix LoadRegionPlugin minDistance computation (#1480)

* Fix LoadRegionPlugin minDistance computation

* Add calculateDistance in LoadRegionPlugin types

Author: xawill

.gitignore

@@ -62,6 +62,7 @@ typings/
 
 # IDEs and editors
 /.idea
+.vscode/settings.json
 
 example/local-data
 example/dev-bundle

src/three/plugins/LoadRegionPlugin.d.ts

@@ -8,6 +8,7 @@ declare class BaseRegion {
 	mask: boolean;
 	constructor( options?: { errorTarget?: number, mask?: boolean } );
 	intersectsTile( boundingVolume: TileBoundingVolume, tile: Tile, tilesRenderer: TilesRenderer ): boolean
+	calculateDistance( boundingVolume: TileBoundingVolume, tile: Tile, tilesRenderer: TilesRenderer ): number
 	calculateError( tile: Tile, tilesRenderer: TilesRenderer ): number
 
 }

src/three/plugins/LoadRegionPlugin.js

@@ -77,7 +77,7 @@ export class LoadRegionPlugin {
 			if ( intersects ) {
 
 				maxError = Math.max( region.calculateError( tile, tiles ), maxError );
-				minDistance = Math.min( region.calculateDistance( boundingVolume, tile, tiles ) );
+				minDistance = Math.min( region.calculateDistance( boundingVolume, tile, tiles ), minDistance );
 
 			}