Merge pull request #200 from NASA-AMMOS/priority-update

TilesRendererBase: Improve default priority behavior

Author: gkjohnson

src/base/TilesRendererBase.d.ts

@@ -46,7 +46,7 @@ export interface Tile {
 	 * How far is this tiles bounds from the nearest active Camera.
 	 * Expected to be filled in during calculateError implementations.
 	 */
-	 __distanceFromCamera : Number;
+	__distanceFromCamera : Number;
 	/**
 	 * This tile is currently active if:
 	 *  1: Tile content is loaded and ready to be made visible if needed
@@ -58,14 +58,20 @@ export interface Tile {
 	 *  2: Tile is within a camera frustum
 	 *  3: Tile meets the SSE requirements
 	 */
-	 __visible : Boolean;
+	__visible : Boolean;
 	/**
-	 * Frame number that this tile was last used: active+visible
+	 * Whether or not the tile was visited during the last update run.
 	 */
-	 __lastFrameVisited : Number;
+	__used : Boolean;
+
+	/**
+	 * Whether or not the tile was within the frustum on the last update run.
+	 */
+	__inFrustum : Boolean;
+
 	/**
 	 * TODO: Document this if it is useful enough to be the default property in the LRU sorting.
 	 */
-	 __depthFromRenderedParent : Number;
+	__depthFromRenderedParent : Number;
 
 }

src/base/TilesRendererBase.js

@@ -14,12 +14,17 @@ import { UNLOADED, LOADING, PARSING, LOADED, FAILED } from './constants.js';
  */
 const priorityCallback = ( a, b ) => {
 
-	if ( a.__lastFrameVisited !== b.__lastFrameVisited ) {
+	if ( a.__inFrustum !== b.__inFrustum ) {
 
-		// the lastFrameVisited tracks the last frame where a tile was used
-		return a.__lastFrameVisited - b.__lastFrameVisited;
+		// prioritize loading whatever is in the frame
+		return a.__inFrustum ? 1 : - 1;
 
-	} else if ( a.__error !== b.__error ) {
+	} else if ( a.__used !== b.__used ) {
+
+		// prioritize tiles that were used most recently
+		return a.__used ? 1 : - 1;
+
+	} if ( a.__error !== b.__error ) {
 
 		// tiles which have greater error next
 		return a.__error - b.__error;

src/three/TilesRenderer.js

@@ -452,6 +452,25 @@ export class TilesRenderer extends TilesRendererBase {
 			vecY.normalize();
 			vecZ.normalize();
 
+			// handle the case where the box has a dimension of 0 in one axis
+			if ( scaleX === 0 ) {
+
+				vecX.crossVectors( vecY, vecZ );
+
+			}
+
+			if ( scaleY === 0 ) {
+
+				vecY.crossVectors( vecX, vecZ );
+
+			}
+
+			if ( scaleZ === 0 ) {
+
+				vecZ.crossVectors( vecX, vecY );
+
+			}
+
 			// create the oriented frame that the box exists in
 			boxTransform.set(
 				vecX.x, vecY.x, vecZ.x, data[ 0 ],