simplify ScanBox use

src/org/oscim/renderer/GLRenderer.java

@@ -73,7 +73,7 @@ public class GLRenderer implements GLSurfaceView.Renderer {
 	// bytes currently loaded in VBOs
 	private static int mBufferMemoryUsage;
 
-	private static float[] mTileCoords;
+	private static float[] mBoxCoords;
 
 	public class Matrices {
 		public final Matrix4 viewproj = new Matrix4();
@@ -183,7 +183,7 @@ public class GLRenderer implements GLSurfaceView.Renderer {
 		mMapPosition = new MapPosition();
 
 		mMatrices = new Matrices();
-		mTileCoords = new float[8];
+		mBoxCoords = new float[8];
 
 		// tile fill coords
 		short min = 0;
@@ -304,7 +304,6 @@ public class GLRenderer implements GLSurfaceView.Renderer {
 
 	/** set tile isVisible flag true for tiles that intersect view */
 	private static void updateTileVisibility() {
-		float[] coords = mTileCoords;
 		MapPosition pos = mMapPosition;
 		MapTile[] tiles = mDrawTiles.tiles;
 
@@ -315,14 +314,11 @@ public class GLRenderer implements GLSurfaceView.Renderer {
 			for (int i = 0; i < mDrawTiles.cnt; i++)
 				tiles[i].isVisible = false;
 
-			// scale and translate projection to tile coordinates
-			ScanBox.transScale(pos.x, pos.y, pos.scale, tileZoom, coords);
-
 			// count placeholder tiles
 			mNumTileHolder = 0;
 
 			// check visibile tiles
-			mScanBox.scan(coords, tileZoom);
+			mScanBox.scan(pos.x, pos.y, pos.scale, tileZoom, mBoxCoords);
 		}
 	}
 
@@ -441,7 +437,7 @@ public class GLRenderer implements GLSurfaceView.Renderer {
 			positionChanged = true;
 		}
 
-		// get current MapPosition, set mTileCoords (mapping of screen to model
+		// get current MapPosition, set mBoxCoords (mapping of screen to model
 		// coordinates)
 		MapPosition pos = mMapPosition;
 
@@ -451,7 +447,7 @@ public class GLRenderer implements GLSurfaceView.Renderer {
 			positionChanged |= mMapViewPosition.getMapPosition(pos);
 
 			if (positionChanged)
-				mMapViewPosition.getMapViewProjection(mTileCoords);
+				mMapViewPosition.getMapViewProjection(mBoxCoords);
 
 			mMapViewPosition.getMatrix(mMatrices.view, null, mMatrices.viewproj);
 

src/org/oscim/renderer/ScanBox.java

@@ -18,14 +18,15 @@ package org.oscim.renderer;
 import org.oscim.core.Tile;
 
 /**
+ * Scan-line fill algorithm to retrieve tile-coordinates.
+ *
  * ScanBox is used to calculate tile coordinates that intersect
- * the box (or trapezoid) which is usually the projection of
- * screen bounds to the map at a given zoom-level.
+ * the box (or trapezoid) which is the projection of screen
+ * bounds to the map.
  *
  * use:
- * MapViewPosition.getMapViewProjection(coords)
- * ScanBox.transScale(pos.x, pos.y, pos.scale, zoomLevel, coords)
- * yourScanBox.scan(coords, zoomLevel);
+ * MapViewPosition.getMapViewProjection(box)
+ * yourScanBox.scan(pos.x, pos.y, pos.scale, zoomLevel, coords);
  *
  * where zoomLevel is the zoom-level for which tile coordinates
  * should be calculated.
@@ -79,9 +80,9 @@ public abstract class ScanBox {
 
 	abstract void setVisible(int y, int x1, int x2);
 
-	public void scan(float[] coords, int zoom) {
+	public void scan(double x, double y, double scale, int zoom, float[] box) {
 		mZoom = zoom;
-
+		transScale(x, y, scale, zoom, box);
 
 		// clip result to min/max as steep angles
 		// cause overshooting in x direction.
@@ -89,11 +90,11 @@ public abstract class ScanBox {
 		float min = Float.MAX_VALUE;
 
 		for(int i = 0; i < 8; i += 2){
-			float x = coords[i];
-			if (x > max)
-				max = x;
-			if (x < min)
-				min = x;
+			float xx = box[i];
+			if (xx > max)
+				max = xx;
+			if (xx < min)
+				min = xx;
 		}
 
 		max = (float)Math.ceil(max);
@@ -105,20 +106,20 @@ public abstract class ScanBox {
 		maxX = (int) max;
 
 		// top-left -> top-right
-		ab.set(coords[0], coords[1], coords[2], coords[3]);
+		ab.set(box[0], box[1], box[2], box[3]);
 		// top-right ->  bottom-right
-		bc.set(coords[2], coords[3], coords[4], coords[5]);
+		bc.set(box[2], box[3], box[4], box[5]);
 		// bottom-right -> bottom-left
-		ca.set(coords[4], coords[5], coords[0], coords[1]);
+		ca.set(box[4], box[5], box[0], box[1]);
 
 		scanTriangle();
 
 		// top-left -> bottom-right
-		ab.set(coords[0], coords[1], coords[4], coords[5]);
+		ab.set(box[0], box[1], box[4], box[5]);
 		// bottom-right -> bottom-left
-		bc.set(coords[4], coords[5], coords[6], coords[7]);
+		bc.set(box[4], box[5], box[6], box[7]);
 		// bottom-left -> top-left
-		ca.set(coords[6], coords[7], coords[0], coords[1]);
+		ca.set(box[6], box[7], box[0], box[1]);
 
 		scanTriangle();
 	}

src/org/oscim/renderer/TileManager.java

@@ -79,7 +79,7 @@ public class TileManager {
 	private TileSet mCurrentTiles;
 	/* package */TileSet mNewTiles;
 
-	private final float[] mTileCoords = new float[8];
+	private final float[] mBoxCoords = new float[8];
 
 	public TileManager(MapView mapView) {
 		mMapView = mapView;
@@ -167,16 +167,12 @@ public class TileManager {
 
 		int tileZoom = FastMath.clamp(pos.zoomLevel, MIN_ZOOMLEVEL, MAX_ZOOMLEVEL);
 
-		float[] coords = mTileCoords;
-		mMapViewPosition.getMapViewProjection(coords);
-
-		// scale and translate projection to tile coordinates
-		ScanBox.transScale(pos.x, pos.y, scale, tileZoom, coords);
+		mMapViewPosition.getMapViewProjection(mBoxCoords);
 
 		// scan visible tiles. callback function calls 'addTile'
-		// which sets mNewTiles
+		// which updates mNewTiles
 		mNewTiles.cnt = 0;
-		mScanBox.scan(coords, tileZoom);
+		mScanBox.scan(pos.x, pos.y, scale, tileZoom, mBoxCoords);
 
 		MapTile[] newTiles = mNewTiles.tiles;
 		MapTile[] curTiles = mCurrentTiles.tiles;