Use exact device screen density on tile details calculation.

worldwind/src/main/java/gov/nasa/worldwind/globe/BasicTessellator.java

@@ -35,7 +35,7 @@ public class BasicTessellator implements Tessellator, TileFactory {
  // ~0.6 meter resolution
  protected LevelSet levelSet = new LevelSet(new Sector().setFullSphere(), new Location(-90, -180), new Location(90, 90), 20, 32, 32);
 
- protected double detailControl = 80;
+ protected double detailControl = 32;
 
  protected final List<Tile> topLevelTiles = new ArrayList<>();
 

worldwind/src/main/java/gov/nasa/worldwind/shape/TiledSurfaceImage.java

@@ -34,16 +34,16 @@ public class TiledSurfaceImage extends AbstractRenderable {
 
  protected ImageOptions imageOptions;
 
- protected double detailControl = 4;
+ protected double detailControl = 1;
 
  protected final List<Tile> topLevelTiles = new ArrayList<>();
 
  /**
  * Memory cache for this layer's subdivision tiles. Each entry contains an array of four image tiles corresponding
- * to the subdivision of the group's common parent tile. The cache is configured to hold 500 groups, a number
+ * to the subdivision of the group's common parent tile. The cache is configured to hold 1000 groups, a number
  * empirically determined to be sufficient for storing the tiles needed to navigate a small region.
  */
- protected final LruMemoryCache<String, Tile[]> tileCache = new LruMemoryCache<>(500);
+ protected final LruMemoryCache<String, Tile[]> tileCache = new LruMemoryCache<>(1000);
 
  protected SurfaceTextureProgram activeProgram;
 
@@ -158,6 +158,10 @@ protected void addTileOrDescendants(RenderContext rc, ImageTile tile) {
  ImageSource tileImageSource = tile.getImageSource();
  if (tileImageSource != null) { // tile has an image source; its level is not empty
  Texture tileTexture = rc.getTexture(tileImageSource);
+ // retrieve top level tiles to avoid black holes when navigating and zooming out camera
+ if (tileTexture == null) {
+ tileTexture = rc.retrieveTexture(tileImageSource, this.imageOptions); // puts retrieved textures in the cache
+ }
  if (tileTexture != null) { // tile has a texture; use it as a fallback tile for descendants
  this.ancestorTile = tile;
  this.ancestorTexture = tileTexture;

worldwind/src/main/java/gov/nasa/worldwind/util/Tile.java

@@ -5,8 +5,6 @@
 
 package gov.nasa.worldwind.util;
 
-import android.util.DisplayMetrics;
-
 import java.util.Arrays;
 import java.util.Collection;
 
@@ -291,14 +289,7 @@ public boolean mustSubdivide(RenderContext rc, double detailFactor) {
  this.distanceToCamera = this.distanceToCamera(rc);
  double texelSize = this.texelSizeFactor * rc.globe.getEquatorialRadius();
  double pixelSize = rc.pixelSizeAtDistance(this.distanceToCamera);
- double densityFactor = 1.0;
-
- // Adjust the subdivision factory when the display density is low. Values of detailFactor have been calibrated
- // against high density devices. Low density devices need roughly half the detailFactor.
- if (rc.resources.getDisplayMetrics().densityDpi <= DisplayMetrics.DENSITY_MEDIUM) {
- densityFactor = 0.5;
- }
-
+ double densityFactor = rc.resources.getDisplayMetrics().density;
  return texelSize > (pixelSize * detailFactor * densityFactor);
  }