change max zoom-level to 24

- fix bug in ScanBox where tiles where not visible when map rotation had a steep angle
- refactor ScanBox, add transScale utility

src/org/oscim/renderer/GLRenderer.java

@@ -310,24 +310,19 @@ public class GLRenderer implements GLSurfaceView.Renderer {
 
 		// lock tiles while updating isVisible state
 		synchronized (GLRenderer.tilelock) {
+			int tileZoom = tiles[0].zoomLevel;
+
 			for (int i = 0; i < mDrawTiles.cnt; i++)
 				tiles[i].isVisible = false;
 
-			int z = tiles[0].zoomLevel;
+			// scale and translate projection to tile coordinates
-
+			ScanBox.transScale(pos.x, pos.y, pos.scale, tileZoom, coords);
-			double curScale = Tile.SIZE * pos.scale;
-			double tileScale = Tile.SIZE * (pos.scale / (1 << z));
-
-			for (int i = 0; i < 8; i += 2) {
-				coords[i + 0] = (float) ((pos.x * curScale + coords[i + 0]) / tileScale);
-				coords[i + 1] = (float) ((pos.y * curScale + coords[i + 1]) / tileScale);
-			}
 
 			// count placeholder tiles
 			mNumTileHolder = 0;
 
 			// check visibile tiles
-			mScanBox.scan(coords, z);
+			mScanBox.scan(coords, tileZoom);
 		}
 	}
 

src/org/oscim/renderer/ScanBox.java

@@ -15,8 +15,37 @@
 
 package org.oscim.renderer;
 
+import org.oscim.core.Tile;
 
+/**
+ * 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.
+ *
+ * use:
+ * MapViewPosition.getMapViewProjection(coords)
+ * ScanBox.transScale(pos.x, pos.y, pos.scale, zoomLevel, coords)
+ * yourScanBox.scan(coords, zoomLevel);
+ *
+ * where zoomLevel is the zoom-level for which tile coordinates
+ * should be calculated.
+ * */
 public abstract class ScanBox {
+
+	public static void transScale(double x, double y, double scale, int zoom, float[] box){
+		scale *= Tile.SIZE;
+
+		//double curScale = Tile.SIZE * scale;
+		double div = scale / (1 << zoom);
+
+		x *= scale;
+		y *= scale;
+
+		for (int i = 0; i < 8; i += 2) {
+			box[i + 0] = (float) ((x + box[i + 0]) / div);
+			box[i + 1] = (float) ((y + box[i + 1]) / div);
+		}
+	}
 	/*
 	 * ported from Polymaps: Layer.js
 	 */
@@ -44,7 +73,7 @@ public abstract class ScanBox {
 	private Edge ab = new Edge();
 	private Edge bc = new Edge();
 	private Edge ca = new Edge();
-	private float minX, maxX;
+	private int minX, maxX;
 
 	protected int mZoom;
 
@@ -53,18 +82,27 @@ public abstract class ScanBox {
 	public void scan(float[] coords, int zoom) {
 		mZoom = zoom;
 
-		maxX = Float.MIN_VALUE;
+
-		minX = Float.MAX_VALUE;
+		// clip result to min/max as steep angles
+		// cause overshooting in x direction.
+		float max = Float.MIN_VALUE;
+		float min = Float.MAX_VALUE;
 
 		for(int i = 0; i < 8; i += 2){
 			float x = coords[i];
-			if (x > maxX)
+			if (x > max)
-				maxX = x;
+				max = x;
-			if (x < minX)
+			if (x < min)
-				minX = x;
+				min = x;
 		}
-		maxX = (float)Math.ceil(maxX);
+
-		minX = (float)Math.floor(minX);
+		max = (float)Math.ceil(max);
+		min = (float)Math.floor(min);
+		if (min == max)
+			max++;
+
+		minX = (int) min;
+		maxX = (int) max;
 
 		// top-left -> top-right
 		ab.set(coords[0], coords[1], coords[2], coords[3]);
@@ -108,10 +146,10 @@ public abstract class ScanBox {
 		if (ca.dy == 0)
 			return;
 
-		if (ab.dy > 0.1)
+		if (ab.dy > 0.0)
 			scanSpans(ca, ab);
 
-		if (bc.dy > 0.1)
+		if (bc.dy > 0.0)
 			scanSpans(ca, bc);
 	}
 
@@ -152,13 +190,13 @@ public abstract class ScanBox {
 			if (dy > e0.dy)
 				dy = e0.dy;
 
-			float x0 = (float)Math.ceil(e0.x0 + m0 * dy);
+			int x0 = (int)Math.ceil(e0.x0 + m0 * dy);
 
 			dy = d1 + y - e1.y0;
 			if (dy > e1.dy)
 				dy = e1.dy;
 
-			float x1 = (float)Math.floor(e1.x0 + m1 * dy);
+			int x1 = (int)Math.floor(e1.x0 + m1 * dy);
 
 			if (x1 < minX)
 				x1 = minX;
@@ -167,7 +205,7 @@ public abstract class ScanBox {
 				x0 = maxX;
 
 			if (x1 < x0)
-				setVisible(y, (int) x1, (int) x0);
+				setVisible(y, x1, x0);
 		}
 	}
 }

src/org/oscim/renderer/TileManager.java

@@ -113,8 +113,8 @@ public class TileManager {
 				clearTile(mTiles[i]);
 		}
 		//else {
-			// mInitialized is set when surface changed
+		// mInitialized is set when surface changed
-			// and VBOs might be lost
+		// and VBOs might be lost
 		//	VertexPool.init();
 		//}
 
@@ -162,26 +162,21 @@ public class TileManager {
 		// jobs come in.
 		mMapView.addJobs(null);
 
-		// scale and translate projection to tile coordinates
 		// load some tiles more than currently visible (* 0.75)
 		double scale = pos.scale * 0.9f;
-		double curScale = Tile.SIZE * scale;
-		int zoomLevel = FastMath.clamp(pos.zoomLevel, MIN_ZOOMLEVEL, MAX_ZOOMLEVEL);
 
-		double tileScale = Tile.SIZE * (scale / (1 << zoomLevel));
+		int tileZoom = FastMath.clamp(pos.zoomLevel, MIN_ZOOMLEVEL, MAX_ZOOMLEVEL);
 
 		float[] coords = mTileCoords;
 		mMapViewPosition.getMapViewProjection(coords);
 
-		for (int i = 0; i < 8; i += 2) {
+		// scale and translate projection to tile coordinates
-			coords[i + 0] = (float) ((pos.x * curScale + coords[i + 0]) / tileScale);
+		ScanBox.transScale(pos.x, pos.y, scale, tileZoom, coords);
-			coords[i + 1] = (float) ((pos.y * curScale + coords[i + 1]) / tileScale);
-		}
 
 		// scan visible tiles. callback function calls 'addTile'
 		// which sets mNewTiles
 		mNewTiles.cnt = 0;
-		mScanBox.scan(coords, zoomLevel);
+		mScanBox.scan(coords, tileZoom);
 
 		MapTile[] newTiles = mNewTiles.tiles;
 		MapTile[] curTiles = mCurrentTiles.tiles;
@@ -562,22 +557,22 @@ public class TileManager {
 	}
 
 	private final ScanBox mScanBox = new ScanBox() {
+
 		@Override
 		public void setVisible(int y, int x1, int x2) {
 			MapTile[] tiles = mNewTiles.tiles;
 			int cnt = mNewTiles.cnt;
-			int max = tiles.length;
+			int maxTiles = tiles.length;
+
 			int xmax = 1 << mZoom;
 
 			for (int x = x1; x < x2; x++) {
 				MapTile tile = null;
 
-				if (cnt == max) {
+				if (cnt == maxTiles) {
-					Log.d(TAG, "reached maximum tiles " + max);
+					Log.d(TAG, "reached maximum tiles " + maxTiles);
 					break;
 				}
-
-				// NOTE to myself: do not modify x!
 				int xx = x;
 
 				if (x < 0 || x >= xmax) {

src/org/oscim/view/MapViewPosition.java

@@ -38,13 +38,14 @@ public class MapViewPosition {
 	private static final String TAG = MapViewPosition.class.getName();
 
 	// needs to fit for int: 2 * 20 * Tile.SIZE
-	public final static int MAX_ZOOMLEVEL = 20;
+	public final static int MAX_ZOOMLEVEL = 24;
 	public final static int MIN_ZOOMLEVEL = 2;
 
 	public final static double MAX_SCALE = (1 << MAX_ZOOMLEVEL);
 	public final static double MIN_SCALE = (1 << MIN_ZOOMLEVEL);
 
-	public final static int ABS_ZOOMLEVEL = 20;
+	// TODO: remove. only used for animations
+	public final static int ABS_ZOOMLEVEL = 22;
 
 	private final static float MAX_ANGLE = 65;