refactor and cleanup RenderElement and related classes

vtm-gdx-html/src/org/oscim/gdx/emu/org/oscim/layers/tile/vector/VectorTileLoader.java

@@ -417,7 +417,7 @@ public class VectorTileLoader extends TileLoader implements IRenderTheme.Callbac
 		if (v != null)
 			minHeight = Integer.parseInt(v);
 
-		ExtrusionLayer l = (ExtrusionLayer) mTile.layers.extrusionLayers;
+		ExtrusionLayer l = mTile.layers.getExtrusionLayers();
 
 		if (l == null) {
 			double lat = MercatorProjection.toLatitude(mTile.y);
@@ -425,7 +425,8 @@ public class VectorTileLoader extends TileLoader implements IRenderTheme.Callbac
 			        * MercatorProjection.EARTH_CIRCUMFERENCE
 			        / ((long) Tile.SIZE << mTile.zoomLevel));
 
-			mTile.layers.extrusionLayers = l = new ExtrusionLayer(0, groundScale, extrusion.colors);
+			l = new ExtrusionLayer(0, groundScale, extrusion.colors);
+			mTile.layers.setExtrusionLayers(l);
 		}
 		l.add(mElement, height, minHeight);
 	}

vtm/src/org/oscim/layers/PathLayer.java

@@ -216,7 +216,7 @@ public class PathLayer extends Layer {
 			mMapPosition.copy(t.pos);
 
 			// compile new layers
-			layers.baseLayers = t.layer.baseLayers;
+			layers.setBaseLayers(t.layer.getBaseLayers());
 			compile();
 		}
 	}
@@ -289,7 +289,7 @@ public class PathLayer extends Layer {
 
 			}
 			if (size == 0) {
-				if (task.layer.baseLayers != null) {
+				if (task.layer.getBaseLayers() != null) {
 					task.layer.clear();
 					mMap.render();
 				}
@@ -299,8 +299,6 @@ public class PathLayer extends Layer {
 			ElementLayers layers = task.layer;
 
 			LineLayer ll = layers.getLineLayer(0);
-			ll.clear();
-
 			ll.line = mLineStyle;
 			ll.width = ll.line.width;
 

vtm/src/org/oscim/layers/marker/ItemizedLayer.java

@@ -115,7 +115,7 @@ public abstract class ItemizedLayer<Item extends MarkerItem> extends MarkerLayer
 
 			synchronized (lock) {
 				if (mItems == null) {
-					if (layers.textureLayers != null) {
+					if (layers.getTextureLayers() != null) {
 						layers.clear();
 						compile();
 					}
@@ -183,10 +183,9 @@ public abstract class ItemizedLayer<Item extends MarkerItem> extends MarkerLayer
 
 					mSymbolLayer.addSymbol(s);
 				}
-
 			}
 			mSymbolLayer.prepare();
-			layers.textureLayers = mSymbolLayer;
+			layers.setTextureLayers(mSymbolLayer);
 
 			compile();
 		}

vtm/src/org/oscim/layers/tile/BitmapTileLayer.java

@@ -141,7 +141,7 @@ public class BitmapTileLayer extends TileLayer<TileLoader> {
 			BitmapLayer l = new BitmapLayer(false);
 			l.setBitmap(bitmap, Tile.SIZE, Tile.SIZE);
 			mTile.layers = new ElementLayers();
-			mTile.layers.textureLayers = l;
+			mTile.layers.setTextureLayers(l);
 		}
 
 		@Override

vtm/src/org/oscim/layers/tile/vector/VectorTileLoader.java

@@ -441,7 +441,7 @@ public class VectorTileLoader extends TileLoader implements IRenderTheme.Callbac
 			        / ((long) Tile.SIZE << mTile.zoomLevel));
 
 			l = new ExtrusionLayer(0, groundScale, extrusion.colors);
-			mTile.layers.add(l);
+			mTile.layers.setExtrusionLayers(l);
 		}
 		l.add(mElement, height, minHeight);
 	}

vtm/src/org/oscim/layers/tile/vector/labeling/TextRenderer.java

@@ -69,7 +69,7 @@ class TextRenderer extends ElementRenderer {
 		}
 
 		// set new TextLayer to be uploaded and rendered
-		layers.textureLayers = t.layers;
+		layers.setTextureLayers(t.layers);
 		mMapPosition = t.pos;
 		compile();
 	}
@@ -85,7 +85,7 @@ class TextRenderer extends ElementRenderer {
 
 		setMatrix(pos, m, false);
 
-		for (RenderElement l = layers.textureLayers; l != null;)
+		for (RenderElement l = layers.getTextureLayers(); l != null;)
 			l = TextureLayer.Renderer.draw(l, scale, m);
 	}
 

vtm/src/org/oscim/renderer/BitmapRenderer.java

@@ -62,7 +62,7 @@ public class BitmapRenderer extends ElementRenderer {
 
 			BitmapLayer l = new BitmapLayer(true);
 			l.setBitmap(mBitmap, mWidth, mHeight);
-			layers.textureLayers = l;
+			layers.setTextureLayers(l);
 
 			mUpdateBitmap = true;
 		}
@@ -86,6 +86,6 @@ public class BitmapRenderer extends ElementRenderer {
 	@Override
 	protected synchronized void render(MapPosition pos, Matrices m) {
 		m.useScreenCoordinates(false, 8);
-		BitmapLayer.Renderer.draw(layers.textureLayers, m, 1, 1);
+		BitmapLayer.Renderer.draw(layers.getTextureLayers(), m, 1, 1);
 	}
 }

vtm/src/org/oscim/renderer/ElementRenderer.java

@@ -16,6 +16,13 @@
  */
 package org.oscim.renderer;
 
+import static org.oscim.renderer.elements.RenderElement.BITMAP;
+import static org.oscim.renderer.elements.RenderElement.LINE;
+import static org.oscim.renderer.elements.RenderElement.MESH;
+import static org.oscim.renderer.elements.RenderElement.POLYGON;
+import static org.oscim.renderer.elements.RenderElement.SYMBOL;
+import static org.oscim.renderer.elements.RenderElement.TEXLINE;
+
 import java.nio.ShortBuffer;
 
 import org.oscim.backend.GL20;
@@ -51,11 +58,15 @@ public abstract class ElementRenderer extends LayerRenderer {
 
 	/**
 	 * Use mMapPosition.copy(position) to keep the position for which
-	 * the Overlay is _compiled_. NOTE: required by setMatrix utility
+	 * the Overlay is *compiled*. NOTE: required by setMatrix utility
 	 * functions to draw this layer fixed to the map
 	 */
 	protected MapPosition mMapPosition;
 
+	/** Wrap around dateline */
+	protected boolean mFlipOnDateLine = true;
+
+	/** Layer data for rendering */
 	public final ElementLayers layers;
 
 	public ElementRenderer() {
@@ -67,59 +78,55 @@ public abstract class ElementRenderer extends LayerRenderer {
 	 * Render all 'layers'
 	 */
 	@Override
-	protected synchronized void render(MapPosition curPos, Matrices m) {
+	protected synchronized void render(MapPosition pos, Matrices m) {
-		MapPosition pos = mMapPosition;
+		MapPosition layerPos = mMapPosition;
-
-		float div = (float) (curPos.scale / pos.scale);
-
-		//float div = FastMath.pow(pos.zoomLevel - curPos.zoomLevel);
 
 		layers.vbo.bind();
 		GLState.test(false, false);
 		GLState.blend(true);
 
-		if (layers.baseLayers != null) {
+		float div = (float) (pos.scale / layerPos.scale);
-			setMatrix(curPos, m, true);
 
-			for (RenderElement l = layers.baseLayers; l != null;) {
+		RenderElement l = layers.getBaseLayers();
-				switch (l.type) {
-					case RenderElement.POLYGON:
-						l = PolygonLayer.Renderer.draw(curPos, l, m, true, 1, false);
-						break;
 
-					case RenderElement.LINE:
+		if (l != null)
-						l = LineLayer.Renderer.draw(layers, l, curPos, m, div);
+			setMatrix(pos, m, true);
-						break;
 
-					case RenderElement.TEXLINE:
+		while (l != null) {
-						l = LineTexLayer.Renderer.draw(layers, l, curPos, m, div);
+			if (l.type == POLYGON) {
-						break;
+				l = PolygonLayer.Renderer.draw(pos, l, m, true, 1, false);
-
+				continue;
-					case RenderElement.MESH:
+			}
+			if (l.type == LINE) {
+				l = LineLayer.Renderer.draw(layers, l, pos, m, div);
+				continue;
+			}
+			if (l.type == TEXLINE) {
+				l = LineTexLayer.Renderer.draw(layers, l, pos, m, div);
+				continue;
+			}
+			if (l.type == MESH) {
 				l = MeshLayer.Renderer.draw(pos, l, m);
-						break;
+				continue;
-
+			}
-					default:
+			log.debug("invalid layer {}", l.type);
-						log.debug("invalid layer");
-						l = l.next;
 			break;
 		}
-			}
-		}
 
-		if (layers.textureLayers != null) {
+		l = layers.getTextureLayers();
-			setMatrix(curPos, m, false);
+		if (l != null)
-
+			setMatrix(pos, m, false);
-			for (RenderElement l = layers.textureLayers; l != null;) {
+		while (l != null) {
-				switch (l.type) {
+			if (l.type == BITMAP) {
-					case RenderElement.BITMAP:
 				l = BitmapLayer.Renderer.draw(l, m, 1, 1);
-						break;
+				continue;
-
+			}
-					default:
+			if (l.type == SYMBOL) {
 				l = TextureLayer.Renderer.draw(l, 1 / div, m);
+				continue;
 			}
-			}
+			log.debug("invalid layer {}", l.type);
+			break;
 		}
 	}
 
@@ -147,7 +154,7 @@ public abstract class ElementRenderer extends LayerRenderer {
 
 	public static boolean uploadLayers(ElementLayers layers, int newSize,
 	        boolean addFill) {
-		// add fill coordinates
+
 		if (addFill)
 			newSize += 8;
 
@@ -192,11 +199,13 @@ public abstract class ElementRenderer extends LayerRenderer {
 		double x = oPos.x - position.x;
 		double y = oPos.y - position.y;
 
-		// wrap around date-line
+		if (mFlipOnDateLine) {
-		//	while (x < -1)
+			//wrap around date-line
-		//		x += 1.0;
+			while (x < 0.5)
-		//	while (x > 2)
+				x += 1.0;
-		//		x -= 1.0;
+			while (x > 0.5)
+				x -= 1.0;
+		}
 
 		matrices.mvp.setTransScale((float) (x * tileScale),
 		                           (float) (y * tileScale),

vtm/src/org/oscim/renderer/ExtrusionRenderer.java

@@ -168,9 +168,9 @@ public class ExtrusionRenderer extends LayerRenderer {
 	}
 
 	private static ExtrusionLayer getLayer(MapTile t) {
-		if (t.layers != null && t.layers.extrusionLayers != null
+		if (t.layers != null && t.layers.getExtrusionLayers() != null
 		        && t.state(MapTile.STATE_READY))
-			return (ExtrusionLayer) t.layers.extrusionLayers;
+			return (ExtrusionLayer) t.layers.getExtrusionLayers();
 		return null;
 	}
 
@@ -200,7 +200,7 @@ public class ExtrusionRenderer extends LayerRenderer {
 			GLState.test(false, false);
 
 			for (int i = 0; i < mTileCnt; i++) {
-				ExtrusionLayer el = (ExtrusionLayer) tiles[i].layers.extrusionLayers;
+				ExtrusionLayer el = tiles[i].layers.getExtrusionLayers();
 
 				setMatrix(pos, m, tiles[i], 0);
 				m.mvp.setAsUniform(uExtMatrix);
@@ -251,7 +251,7 @@ public class ExtrusionRenderer extends LayerRenderer {
 		// draw to depth buffer
 		for (int i = 0; i < mTileCnt; i++) {
 			MapTile t = tiles[i];
-			ExtrusionLayer el = (ExtrusionLayer) t.layers.extrusionLayers;
+			ExtrusionLayer el = t.layers.getExtrusionLayers();
 			int d = MapRenderer.depthOffset(t) * 10;
 			setMatrix(pos, m, t, d);
 			m.mvp.setAsUniform(uExtMatrix);
@@ -277,7 +277,7 @@ public class ExtrusionRenderer extends LayerRenderer {
 
 		for (int i = 0; i < mTileCnt; i++) {
 			MapTile t = tiles[i];
-			ExtrusionLayer el = (ExtrusionLayer) t.layers.extrusionLayers;
+			ExtrusionLayer el = t.layers.getExtrusionLayers();
 
 			if (el.colors == null) {
 				currentColor = mColor;

vtm/src/org/oscim/renderer/GridRenderer.java

@@ -137,7 +137,8 @@ public class GridRenderer extends ElementRenderer {
 
 		if (mText != null) {
 			addLabels(x, y, pos.zoomLevel);
-			mLineLayer.clear();
+
+			layers.setBaseLayers(mLineLayer);
 			mLineLayer.addLine(mLines);
 		}
 

vtm/src/org/oscim/renderer/elements/BitmapLayer.java

@@ -106,7 +106,7 @@ public class BitmapLayer extends TextureLayer {
 		buf[pos++] = texMax;
 		buf[pos++] = texMax;
 
-		setOffset(sbuf.position() * 2);
+		this.offset = sbuf.position() * 2;
 		sbuf.put(buf);
 	}
 
@@ -215,7 +215,7 @@ public class BitmapLayer extends TextureLayer {
 				// draw up to maxVertices in each iteration
 				for (int i = 0; i < t.vertices; i += maxVertices) {
 					// to.offset * (24(shorts) * 2(short-bytes) / 6(indices) == 8)
-					int off = (t.offset + i) * 8 + tl.getOffset();
+					int off = (t.offset + i) * 8 + tl.offset;
 
 					GL.glVertexAttribPointer(hTextureVertex, 4,
 					                         GL20.GL_SHORT, false, 12, off);

vtm/src/org/oscim/renderer/elements/ElementLayers.java

@@ -16,15 +16,24 @@
  */
 package org.oscim.renderer.elements;
 
+import static org.oscim.renderer.elements.RenderElement.LINE;
+import static org.oscim.renderer.elements.RenderElement.MESH;
+import static org.oscim.renderer.elements.RenderElement.POLYGON;
+import static org.oscim.renderer.elements.RenderElement.TEXLINE;
+
 import java.nio.ShortBuffer;
 
 import org.oscim.backend.GL20;
 import org.oscim.renderer.BufferObject;
 import org.oscim.theme.styles.Line;
-import org.oscim.utils.pool.Inlist;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+/**
+ * This class is primarily intended for rendering the vector elements of a
+ * MapTile. It can be used for other purposes as well but some optimizations
+ * applied probably wont make sense in different contexts.
+ */
 public class ElementLayers {
 	static final Logger log = LoggerFactory.getLogger(ElementLayers.class);
 
@@ -42,12 +51,13 @@ public class ElementLayers {
 	}
 
 	/** mixed Polygon- and LineLayer */
-	public RenderElement baseLayers;
+	private RenderElement baseLayers;
 
 	/** Text- and SymbolLayer */
-	public RenderElement textureLayers;
+	private RenderElement textureLayers;
+
+	private RenderElement extrusionLayers;
 
-	public RenderElement extrusionLayers;
 	/**
 	 * VBO holds all vertex data to draw lines and polygons after compilation.
 	 * Layout:
@@ -62,10 +72,9 @@ public class ElementLayers {
 	 * To not need to switch VertexAttribPointer positions all the time:
 	 * 1. polygons are packed in VBO at offset 0
 	 * 2. lines afterwards at lineOffset
-	 * 3. other layers keep their byte offset in RenderElement.offset
+	 * 3. other layers keep their byte offset in offset
 	 */
-	public int lineOffset;
+	public int[] offset = { 0, 0 };
-	public int texLineOffset;
 
 	private RenderElement mCurLayer;
 
@@ -74,7 +83,7 @@ public class ElementLayers {
 	 * ordered from bottom (0) to top
 	 */
 	public LineLayer addLineLayer(int level, Line style) {
-		LineLayer ll = (LineLayer) getLayer(level, RenderElement.LINE);
+		LineLayer ll = (LineLayer) getLayer(level, LINE);
 		if (ll == null)
 			return null;
 
@@ -89,7 +98,7 @@ public class ElementLayers {
 	 * bottom (0) to top
 	 */
 	public LineLayer getLineLayer(int level) {
-		return (LineLayer) getLayer(level, RenderElement.LINE);
+		return (LineLayer) getLayer(level, LINE);
 	}
 
 	/**
@@ -97,7 +106,7 @@ public class ElementLayers {
 	 * bottom (0) to top
 	 */
 	public MeshLayer getMeshLayer(int level) {
-		return (MeshLayer) getLayer(level, RenderElement.MESH);
+		return (MeshLayer) getLayer(level, MESH);
 	}
 
 	/**
@@ -105,7 +114,7 @@ public class ElementLayers {
 	 * bottom (0) to top
 	 */
 	public PolygonLayer getPolygonLayer(int level) {
-		return (PolygonLayer) getLayer(level, RenderElement.POLYGON);
+		return (PolygonLayer) getLayer(level, POLYGON);
 	}
 
 	/**
@@ -113,7 +122,7 @@ public class ElementLayers {
 	 * bottom (0) to top
 	 */
 	public LineTexLayer getLineTexLayer(int level) {
-		return (LineTexLayer) getLayer(level, RenderElement.TEXLINE);
+		return (LineTexLayer) getLayer(level, TEXLINE);
 	}
 
 	public TextLayer addTextLayer(TextLayer textLayer) {
@@ -122,32 +131,76 @@ public class ElementLayers {
 		return textLayer;
 	}
 
-	private RenderElement getLayer(int level, byte type) {
+	public void setBaseLayers(RenderElement layers) {
-		RenderElement l = baseLayers;
+		for (RenderElement l = baseLayers; l != null; l = l.next)
-		RenderElement renderElement = null;
+			l.clear();
 
-		if (!(type == RenderElement.LINE
+		baseLayers = layers;
-		        || type == RenderElement.POLYGON
+	}
-		        || type == RenderElement.TEXLINE
+
-		        || type == RenderElement.MESH))
+	public RenderElement getBaseLayers() {
-			throw new IllegalArgumentException("invalid layer type");
+		return baseLayers;
+	}
+
+	public void setTextureLayers(TextureLayer tl) {
+		for (RenderElement l = textureLayers; l != null; l = l.next)
+			l.clear();
+
+		textureLayers = tl;
+	}
+
+	public RenderElement getTextureLayers() {
+		return textureLayers;
+	}
+
+	public void setExtrusionLayers(ExtrusionLayer el) {
+		for (RenderElement l = extrusionLayers; l != null; l = l.next)
+			l.clear();
+
+		extrusionLayers = el;
+	}
+
+	public ExtrusionLayer getExtrusionLayers() {
+		return (ExtrusionLayer) extrusionLayers;
+	}
+
+	/** cleanup only when layers are not used by tile or overlay anymore! */
+	public void clear() {
+		setBaseLayers(null);
+		setTextureLayers(null);
+		setExtrusionLayers(null);
+		mCurLayer = null;
+
+		if (vbo != null)
+			vbo = BufferObject.release(vbo);
+	}
+
+	private RenderElement getLayer(int level, int type) {
+		RenderElement layer = null;
 
 		if (mCurLayer != null && mCurLayer.level == level) {
-			renderElement = mCurLayer;
+			layer = mCurLayer;
-		} else {
+			if (layer.type != type) {
+				log.error("BUG wrong layer {} {} on layer {}",
+				          layer.type, type, level);
 
+				throw new IllegalArgumentException();
+			}
+			return layer;
+		}
+
+		RenderElement l = baseLayers;
 		if (l == null || l.level > level) {
-				// insert new layer at start
+			/** insert new layer at start */
 			l = null;
 		} else {
 			while (true) {
-					// found layer
+				/** found layer */
 				if (l.level == level) {
-						renderElement = l;
+					layer = l;
 					break;
 				}
-
+				/** insert layer between current and next layer */
-					// insert new layer between current and next layer
 				if (l.next == null || l.next.level > level)
 					break;
 
@@ -155,53 +208,50 @@ public class ElementLayers {
 			}
 		}
 
-			if (renderElement == null) {
+		if (layer == null) {
-				// add a new RenderElement
+			/** add a new RenderElement */
-				if (type == RenderElement.LINE)
+			if (type == LINE)
-					renderElement = new LineLayer(level);
+				layer = new LineLayer(level);
-				else if (type == RenderElement.POLYGON)
+			else if (type == POLYGON)
-					renderElement = new PolygonLayer(level);
+				layer = new PolygonLayer(level);
-				else if (type == RenderElement.TEXLINE)
+			else if (type == TEXLINE)
-					renderElement = new LineTexLayer(level);
+				layer = new LineTexLayer(level);
-				else if (type == RenderElement.MESH)
+			else if (type == MESH)
-					renderElement = new MeshLayer(level);
+				layer = new MeshLayer(level);
 
-				if (renderElement == null)
+			if (layer == null)
 				throw new IllegalArgumentException();
 
 			if (l == null) {
-					// insert at start
+				/** insert at start */
-					renderElement.next = baseLayers;
+				layer.next = baseLayers;
-					baseLayers = renderElement;
+				baseLayers = layer;
 			} else {
-					renderElement.next = l.next;
+				layer.next = l.next;
-					l.next = renderElement;
+				l.next = layer;
-				}
 			}
 		}
 
-		if (renderElement.type != type) {
+		/** check if found layer matches requested type */
-			// check if found layer matches requested type
+		if (layer.type != type) {
-			log.debug("BUG wrong layer " + renderElement.type + " " + type +
+			log.error("BUG wrong layer {} {} on layer {}",
-			        " on layer " + renderElement.level);
+			          layer.type, type, level);
-
 			throw new IllegalArgumentException();
 		}
 
-		mCurLayer = renderElement;
+		mCurLayer = layer;
 
-		return renderElement;
+		return layer;
 	}
 
 	private final static int[] VERTEX_SHORT_CNT = {
 	        4, // LINE_VERTEX_SHORTS
+	        6, // TEXLINE_VERTEX_SHORTS
 	        2, // POLY_VERTEX_SHORTS
 	        2, // MESH_VERTEX_SHORTS
-	        6, // TEXLINE_VERTEX_SHORTS
 	};
 
 	private final static int TEXTURE_VERTEX_SHORTS = 6;
-
 	private final static int SHORT_BYTES = 2;
 
 	public int getSize() {
@@ -217,51 +267,32 @@ public class ElementLayers {
 	}
 
 	public void compile(ShortBuffer sbuf, boolean addFill) {
-		// offset from fill coordinates
-		int pos = 0;
-		int size = 0;
 
-		if (addFill) {
+		addLayerItems(sbuf, baseLayers, POLYGON, addFill ? 4 : 0);
-			pos = 4;
-			size = 8;
-		}
 
-		size += addLayerItems(sbuf, baseLayers, RenderElement.POLYGON, pos);
+		offset[LINE] = sbuf.position() * SHORT_BYTES;
+		addLayerItems(sbuf, baseLayers, LINE, 0);
 
-		lineOffset = size * SHORT_BYTES;
+		//offset[TEXLINE] = size * SHORT_BYTES;
-		size += addLayerItems(sbuf, baseLayers, RenderElement.LINE, 0);
-
-		texLineOffset = size * SHORT_BYTES;
 
 		for (RenderElement l = baseLayers; l != null; l = l.next) {
-			if (l.type == RenderElement.TEXLINE) {
+			if (l.type == TEXLINE || l.type == MESH) {
-				addPoolItems(l, sbuf);
-				// add additional vertex for interleaving,
-				// see TexLineLayer.
-				sbuf.position(sbuf.position() + 6);
-			}
-		}
-
-		for (RenderElement l = baseLayers; l != null; l = l.next) {
-			if (l.type == RenderElement.MESH)
 				l.compile(sbuf);
 			}
+		}
 
 		for (RenderElement l = textureLayers; l != null; l = l.next) {
-			//TextureLayer tl = (TextureLayer) l;
 			l.compile(sbuf);
 		}
-
-		// extrusion layers are compiled by extrusion overlay
-		//		for (RenderElement l = extrusionLayers; l != null; l = l.next) {
-		//			ExtrusionLayer tl = (ExtrusionLayer) l;
-		//			tl.compile(sbuf);
-		//		}
 	}
 
-	// optimization for Line- and PolygonLayer:
+	/**
-	// collect all pool items and add back in one go
+	 * optimization for Line- and PolygonLayer:
-	private static int addLayerItems(ShortBuffer sbuf, RenderElement l, byte type, int pos) {
+	 * collect all pool items and add back in one go.
+	 */
+	private static int addLayerItems(ShortBuffer sbuf, RenderElement l,
+	        int type, int pos) {
+
 		VertexItem last = null, items = null;
 		int size = 0;
 
@@ -283,7 +314,7 @@ public class ElementLayers {
 			if (last == null)
 				continue;
 
-			l.setOffset(pos);
+			l.offset = pos;
 			pos += l.numVertices;
 
 			last.next = items;
@@ -298,8 +329,8 @@ public class ElementLayers {
 	}
 
 	static void addPoolItems(RenderElement l, ShortBuffer sbuf) {
-		// offset of layer data in vbo
+		/** keep offset of layer data in vbo */
-		l.setOffset(sbuf.position() * SHORT_BYTES);
+		l.offset = sbuf.position() * SHORT_BYTES;
 
 		for (VertexItem it = l.vertexItems; it != null; it = it.next) {
 			if (it.next == null)
@@ -310,39 +341,4 @@ public class ElementLayers {
 
 		l.vertexItems = VertexItem.pool.releaseAll(l.vertexItems);
 	}
-
-	// cleanup only when layers are not used by tile or overlay anymore!
-	public void clear() {
-
-		// clear line and polygon layers directly
-		for (RenderElement l = baseLayers; l != null; l = l.next) {
-			if (l.vertexItems != null)
-				l.vertexItems = VertexItem.pool.releaseAll(l.vertexItems);
-			l.numVertices = 0;
-		}
-
-		for (RenderElement l = textureLayers; l != null; l = l.next)
-			l.clear();
-
-		for (RenderElement l = extrusionLayers; l != null; l = l.next)
-			l.clear();
-
-		baseLayers = null;
-		textureLayers = null;
-		extrusionLayers = null;
-		mCurLayer = null;
-		//		if (vbo != null){
-		//			BufferObject.release(vbo);
-		//			vbo = null;
-		//		}
-	}
-
-	public void add(ExtrusionLayer l) {
-		extrusionLayers = Inlist.appendItem(extrusionLayers, l);
-	}
-
-	public ExtrusionLayer getExtrusionLayers() {
-		return (ExtrusionLayer) extrusionLayers;
-	}
-
 }

vtm/src/org/oscim/renderer/elements/LineLayer.java

@@ -16,8 +16,6 @@
  */
 package org.oscim.renderer.elements;
 
-import java.nio.ShortBuffer;
-
 import org.oscim.backend.GL20;
 import org.oscim.backend.GLAdapter;
 import org.oscim.backend.canvas.Paint.Cap;
@@ -556,16 +554,6 @@ public final class LineLayer extends RenderElement {
 		si.used = opos;
 	}
 
-	@Override
-	public void clear() {
-		vertexItems = VertexItem.pool.releaseAll(vertexItems);
-		numVertices = 0;
-	}
-
-	@Override
-	protected void compile(ShortBuffer sbuf) {
-	}
-
 	public static final class Renderer {
 		// TODO: http://http.developer.nvidia.com/GPUGems2/gpugems2_chapter22.html
 
@@ -668,7 +656,7 @@ public final class LineLayer extends RenderElement {
 			GLState.enableVertexArrays(hLineVertexPosition[mode], -1);
 
 			GL.glVertexAttribPointer(hLineVertexPosition[mode], 4, GL20.GL_SHORT,
-			                         false, 0, layers.lineOffset);
+			                         false, 0, layers.offset[LINE]);
 
 			m.mvp.setAsUniform(hLineMatrix[mode]);
 
@@ -745,7 +733,7 @@ public final class LineLayer extends RenderElement {
 					}
 
 					GL.glDrawArrays(GL20.GL_TRIANGLE_STRIP,
-					                l.getOffset(), l.numVertices);
+					                l.offset, l.numVertices);
 
 					continue;
 				}
@@ -781,7 +769,7 @@ public final class LineLayer extends RenderElement {
 					}
 
 					GL.glDrawArrays(GL20.GL_TRIANGLE_STRIP,
-					                o.getOffset(), o.numVertices);
+					                o.offset, o.numVertices);
 				}
 			}
 

vtm/src/org/oscim/renderer/elements/LineTexLayer.java

@@ -246,12 +246,12 @@ public final class LineTexLayer extends RenderElement {
 		si.used = opos;
 	}
 
-	@Override
-	protected void clear() {
-	}
-
 	@Override
 	protected void compile(ShortBuffer sbuf) {
+		ElementLayers.addPoolItems(this, sbuf);
+		// add additional vertex for interleaving,
+		// see TexLineLayer.
+		sbuf.position(sbuf.position() + 6);
 	}
 
 	public final static class Renderer {
@@ -369,7 +369,6 @@ public final class LineTexLayer extends RenderElement {
 			for (; l != null && l.type == RenderElement.TEXLINE; l = l.next) {
 				LineTexLayer ll = (LineTexLayer) l;
 				Line line = ll.line;
-				int lOffset = l.getOffset();
 
 				GLUtils.setColor(hTexColor, line.stippleColor, 1);
 				GLUtils.setColor(hBgColor, line.color, 1);
@@ -396,7 +395,7 @@ public final class LineTexLayer extends RenderElement {
 						numIndices = maxIndices;
 
 					// i / 6 * (24 shorts per block * 2 short bytes)
-					int add = (lOffset + i * 8) + vOffset;
+					int add = (l.offset + i * 8) + vOffset;
 
 					GL.glVertexAttribPointer(hVertexPosition0,
 					                         4, GL20.GL_SHORT, false, STRIDE,
@@ -425,7 +424,7 @@ public final class LineTexLayer extends RenderElement {
 					if (numIndices > maxIndices)
 						numIndices = maxIndices;
 					// i / 6 * (24 shorts per block * 2 short bytes)
-					int add = (lOffset + i * 8) + vOffset;
+					int add = (l.offset + i * 8) + vOffset;
 
 					GL.glVertexAttribPointer(hVertexPosition0,
 					                         4, GL20.GL_SHORT, false, STRIDE,

vtm/src/org/oscim/renderer/elements/MeshLayer.java

@@ -144,7 +144,7 @@ public class MeshLayer extends RenderElement {
 					GLUtils.setColor(hColor, ml.area.color, 1);
 
 				GL.glVertexAttribPointer(hVertexPosition, 2, GL20.GL_SHORT,
-				                         false, 0, ml.getOffset());
+				                         false, 0, ml.offset);
 
 				GL.glDrawElements(GL20.GL_TRIANGLES, ml.numIndices,
 				                  GL20.GL_UNSIGNED_SHORT, 0);

vtm/src/org/oscim/renderer/elements/PolygonLayer.java

@@ -19,7 +19,6 @@ package org.oscim.renderer.elements;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.nio.FloatBuffer;
-import java.nio.ShortBuffer;
 
 import org.oscim.backend.GL20;
 import org.oscim.backend.GLAdapter;
@@ -117,14 +116,6 @@ public final class PolygonLayer extends RenderElement {
 		si.used = outPos;
 	}
 
-	@Override
-	protected void compile(ShortBuffer sbuf) {
-	}
-
-	@Override
-	protected void clear() {
-	}
-
 	public static final class Renderer {
 
 		private static final int POLYGON_VERTICES_DATA_POS_OFFSET = 0;
@@ -326,7 +317,7 @@ public final class PolygonLayer extends RenderElement {
 				// set stencil mask to draw to
 				GL.glStencilMask(1 << cur++);
 
-				GL.glDrawArrays(GL20.GL_TRIANGLE_FAN, l.getOffset(), l.numVertices);
+				GL.glDrawArrays(GL20.GL_TRIANGLE_FAN, l.offset, l.numVertices);
 
 				// draw up to 7 layers into stencil buffer
 				if (cur == STENCIL_BITS - 1) {

vtm/src/org/oscim/renderer/elements/RenderElement.java

@@ -24,45 +24,45 @@ import org.oscim.utils.pool.Inlist;
 public abstract class RenderElement extends Inlist<RenderElement> {
 	protected static GL20 GL;
 
-	public final static byte LINE = 0;
+	public final static int LINE = 0;
-	public final static byte POLYGON = 1;
+	public final static int TEXLINE = 1;
-	public final static byte MESH = 2;
+	public final static int POLYGON = 2;
-	public final static byte TEXLINE = 3;
+	public final static int MESH = 3;
-	public final static byte SYMBOL = 4;
+	public final static int SYMBOL = 4;
-	public final static byte BITMAP = 5;
+	public final static int BITMAP = 5;
-	public final static byte EXTRUSION = 6;
+	public final static int EXTRUSION = 6;
 
-	protected RenderElement(byte type) {
+	public final int type;
+
+	/** drawing order from bottom to top. */
+	int level;
+
+	/** number of vertices for this layer. */
+	protected int numVertices;
+
+	/** temporary list of vertex data. */
+	protected VertexItem vertexItems;
+
+	protected RenderElement(int type) {
 		this.type = type;
 	}
 
-	public final byte type;
+	/** clear all resources. */
+	protected void clear() {
+		if (vertexItems != null)
+			vertexItems = VertexItem.pool.releaseAll(vertexItems);
+		numVertices = 0;
+	}
 
-	/** drawing order from bottom to top */
+	/** compile vertex data to vbo. */
-	int level;
+	protected void compile(ShortBuffer sbuf) {
 
-	/** number of vertices for this layer */
+	}
-	protected int numVertices;
-
-	protected VertexItem vertexItems;
-
-	abstract protected void compile(ShortBuffer sbuf);
-
-	abstract protected void clear();
 
 	/**
-	 * for line and polygon layers:
+	 * For line- and polygon-layers this is the offset
-	 * - number of VERTICES mOffset for this layertype in VBO
+	 * of VERTICES in its layers.vbo.
-	 * otherwise:
+	 * For all other types it is the byte offset in vbo.
-	 * - offset in byte in VBO
 	 */
-	private int mOffset;
+	protected int offset;
-
-	public int getOffset() {
-		return mOffset;
-	}
-
-	public void setOffset(int offset) {
-		mOffset = offset;
-	}
 }

vtm/src/org/oscim/renderer/elements/SymbolLayer.java

@@ -62,7 +62,7 @@ public final class SymbolLayer extends TextureLayer {
 	@Override
 	protected void compile(ShortBuffer sbuf) {
 		// offset of layer data in vbo
-		setOffset(sbuf.position() * 2); //SHORT_BYTES;
+		this.offset = sbuf.position() * 2; //SHORT_BYTES;
 
 		short numIndices = 0;
 

vtm/src/org/oscim/renderer/elements/TextureLayer.java

@@ -42,7 +42,7 @@ public abstract class TextureLayer extends RenderElement {
 	                                                TEXTURE_WIDTH,
 	                                                TEXTURE_HEIGHT);
 
-	protected TextureLayer(byte type) {
+	protected TextureLayer(int type) {
 		super(type);
 	}
 
@@ -174,7 +174,7 @@ public abstract class TextureLayer extends RenderElement {
 				// draw up to maxVertices in each iteration
 				for (int i = 0; i < t.vertices; i += maxVertices) {
 					// to.offset * (24(shorts) * 2(short-bytes) / 6(indices) == 8)
-					int off = (t.offset + i) * 8 + tl.getOffset();
+					int off = (t.offset + i) * 8 + tl.offset;
 
 					GL.glVertexAttribPointer(hTextureVertex, 4,
 					                         GL20.GL_SHORT, false, 12, off);

vtm/src/org/oscim/renderer/test/AtlasRenderLayer.java

@@ -56,7 +56,7 @@ public class AtlasRenderLayer extends ElementRenderer {
 
 		TextLayer tl = new TextLayer();
 		Text t = Text.createText(20, 0, Color.BLACK, 0, false);
-		layers.textureLayers = tl;
+		layers.setTextureLayers(tl);
 
 		float[] points = new float[10];
 

vtm/src/org/oscim/renderer/test/SymbolRenderLayer.java

@@ -28,7 +28,7 @@ public class SymbolRenderLayer extends ElementRenderer {
 
 	public SymbolRenderLayer() {
 		SymbolLayer l = new SymbolLayer();
-		layers.textureLayers = l;
+		layers.setTextureLayers(l);
 
 		SymbolItem it = SymbolItem.pool.get();
 		it.billboard = false;

vtm/src/org/oscim/tiling/MapTile.java

@@ -17,7 +17,6 @@
 package org.oscim.tiling;
 
 import org.oscim.core.Tile;
-import org.oscim.renderer.BufferObject;
 import org.oscim.renderer.elements.ElementLayers;
 import org.oscim.renderer.elements.SymbolItem;
 import org.oscim.renderer.elements.TextItem;
@@ -226,8 +225,6 @@ public class MapTile extends Tile {
 	 */
 	protected void clear() {
 		if (layers != null) {
-			// TODO move this to layers clear
-			layers.vbo = BufferObject.release(layers.vbo);
 			layers.clear();
 			layers = null;
 		}

vtm/src/org/oscim/tiling/TileRenderer.java

@@ -16,6 +16,11 @@
  */
 package org.oscim.tiling;
 
+import static org.oscim.renderer.elements.RenderElement.BITMAP;
+import static org.oscim.renderer.elements.RenderElement.LINE;
+import static org.oscim.renderer.elements.RenderElement.MESH;
+import static org.oscim.renderer.elements.RenderElement.POLYGON;
+import static org.oscim.renderer.elements.RenderElement.TEXLINE;
 import static org.oscim.tiling.MapTile.STATE_NEW_DATA;
 import static org.oscim.tiling.MapTile.STATE_READY;
 
@@ -178,7 +183,8 @@ public class TileRenderer extends LayerRenderer {
 			return 1;
 
 		int newSize = tile.layers.getSize();
-		if (newSize > 0) {
+		if (newSize <= 0)
+			return 1;
 
 		if (tile.layers.vbo == null)
 			tile.layers.vbo = BufferObject.get(GL20.GL_ARRAY_BUFFER, newSize);
@@ -191,7 +197,6 @@ public class TileRenderer extends LayerRenderer {
 			tile.layers = null;
 			return 0;
 		}
-		}
 
 		return 1;
 	}
@@ -395,7 +400,8 @@ public class TileRenderer extends LayerRenderer {
 		for (int i = 0; i < tileCnt; i++) {
 			MapTile t = tiles[i];
 			if (t.isVisible && (t.state != STATE_READY) && (t.holder == null)) {
-				boolean preferParent = (scale > 1.5) || (pos.zoomLevel - t.zoomLevel < 0);
+				boolean preferParent = (scale > 1.5)
+				        || (pos.zoomLevel - t.zoomLevel < 0);
 				drawProxyTile(t, pos, true, preferParent);
 			}
 		}
@@ -416,33 +422,29 @@ public class TileRenderer extends LayerRenderer {
 	}
 
 	private void drawTile(MapTile tile, MapPosition pos) {
-		// draw parents only once
+		/** ensure to draw parents only once */
 		if (tile.lastDraw == mDrawSerial)
 			return;
 
 		tile.lastDraw = mDrawSerial;
 
-		MapTile t = tile;
+		/** use holder proxy when it is set */
-		if (t.holder != null)
+		MapTile t = tile.holder == null ? tile : tile.holder;
-			t = t.holder;
 
-		if (t.layers == null || t.layers.vbo == null) {
+		if (t.layers == null || t.layers.vbo == null)
-			//log.debug("missing data " + (t.layers == null) + " " + (t.vbo == null));
+			//throw new IllegalStateException(t + "no data " + (t.layers == null));
 			return;
-		}
 
 		t.layers.vbo.bind();
 
-		// place tile relative to map position
+		/** place tile relative to map position */
 		int z = tile.zoomLevel;
-
 		float div = FastMath.pow(z - pos.zoomLevel);
-
 		double tileScale = Tile.SIZE * pos.scale;
 		float x = (float) ((tile.x - pos.x) * tileScale);
 		float y = (float) ((tile.y - pos.y) * tileScale);
 
-		// scale relative to zoom-level of this tile
+		/** scale relative to zoom-level of this tile */
 		float scale = (float) (pos.scale / (1 << z));
 
 		Matrices m = mMatrices;
@@ -450,64 +452,46 @@ public class TileRenderer extends LayerRenderer {
 		m.mvp.multiplyLhs(m.viewproj);
 
 		boolean clipped = false;
+		RenderElement l = t.layers.getBaseLayers();
 
-		for (RenderElement l = t.layers.baseLayers; l != null;) {
+		while (l != null) {
-			switch (l.type) {
+			if (l.type == POLYGON) {
-				case RenderElement.POLYGON:
 				l = PolygonLayer.Renderer.draw(pos, l, m, !clipped, div, true);
 				clipped = true;
-					break;
+				continue;
-
-				case RenderElement.LINE:
-					if (!clipped) {
-						clipped = true;
-						PolygonLayer.Renderer.draw(pos, null, m, true, div, true);
 			}
-					l = LineLayer.Renderer.draw(t.layers, l, pos, m, scale);
-					break;
-
-				case RenderElement.TEXLINE:
-					if (!clipped) {
-						clipped = true;
-						PolygonLayer.Renderer.draw(pos, null, m, true, div, true);
-					}
-					l = LineTexLayer.Renderer.draw(t.layers, l, pos, m, div);
-					break;
-
-				case RenderElement.MESH:
-					if (!clipped) {
-						clipped = true;
-						PolygonLayer.Renderer.draw(pos, null, m, true, div, true);
-					}
-					l = MeshLayer.Renderer.draw(pos, l, m);
-					break;
-
-				default:
-					// just in case
-					l = l.next;
-			}
-		}
-
-		for (RenderElement l = t.layers.textureLayers; l != null;) {
 			if (!clipped) {
 				// draw stencil buffer clip region
 				PolygonLayer.Renderer.draw(pos, null, m, true, div, true);
 				clipped = true;
 			}
-			//			if (!clipped) {
+			if (l.type == LINE) {
-			//				// draw stencil buffer clip region
+				l = LineLayer.Renderer.draw(t.layers, l, pos, m, scale);
-			//				PolygonRenderer.clip(m);
+				continue;
-			//				clipped = true;
+			}
-			//			}
+			if (l.type == TEXLINE) {
-			//GLState.test(false, false);
+				l = LineTexLayer.Renderer.draw(t.layers, l, pos, m, div);
-			switch (l.type) {
+				continue;
-				case RenderElement.BITMAP:
+			}
-					l = BitmapLayer.Renderer.draw(l, m, 1, mRenderAlpha);
+			if (l.type == MESH) {
-					break;
+				l = MeshLayer.Renderer.draw(pos, l, m);
-
+				continue;
-				default:
+			}
+			// just in case
 			l = l.next;
 		}
+
+		l = t.layers.getTextureLayers();
+		while (l != null) {
+			if (!clipped) {
+				PolygonLayer.Renderer.draw(pos, null, m, true, div, true);
+				clipped = true;
+			}
+			if (l.type == BITMAP) {
+				l = BitmapLayer.Renderer.draw(l, m, 1, mRenderAlpha);
+				continue;
+			}
+			l = l.next;
 		}
 
 		if (t.fadeTime == 0)