use depth clipping again but only when proxy tiles are drawn

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

@@ -94,7 +94,7 @@ public abstract class ElementRenderer extends LayerRenderer {
 
 		while (l != null) {
 			if (l.type == POLYGON) {
-				l = PolygonLayer.Renderer.draw(pos, l, m, true, 1, false);
+				l = PolygonLayer.Renderer.draw(pos, l, m, true, 1, 0);
 				continue;
 			}
 			if (l.type == LINE) {

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

@@ -279,7 +279,7 @@ public final class PolygonLayer extends RenderElement {
 		 *         next layer
 		 */
 		public static RenderElement draw(MapPosition pos, RenderElement renderElement,
-		        Matrices m, boolean first, float div, boolean clip) {
+		        Matrices m, boolean first, float div, int clip) {
 
 			GLState.test(false, true);
 
@@ -305,7 +305,7 @@ public final class PolygonLayer extends RenderElement {
 					continue;
 
 				if (cur == start) {
-					drawStencilRegion(first);
+					drawStencilRegion(first, clip);
 					first = false;
 
 					// op for stencil method polygon drawing
@@ -329,9 +329,9 @@ public final class PolygonLayer extends RenderElement {
 			if (cur > 0)
 				fillPolygons(m, start, cur, zoom, scale, div);
 
-			if (clip) {
+			if (clip > 0) {
 				if (first) {
-					drawStencilRegion(first);
+					drawStencilRegion(first, clip);
 					// disable writes to stencil buffer
 					GL.glStencilMask(0x00);
 					// enable writes to color buffer
@@ -350,7 +350,7 @@ public final class PolygonLayer extends RenderElement {
 		public static void clip(Matrices m) {
 			setShader(polyShader, m);
 
-			drawStencilRegion(true);
+			drawStencilRegion(true, 1);
 			// disable writes to stencil buffer
 			GL.glStencilMask(0x00);
 			// enable writes to color buffer
@@ -364,7 +364,7 @@ public final class PolygonLayer extends RenderElement {
 		 * @param first in the first run the clip region is set based on
 		 *            depth buffer and depth buffer is updated
 		 */
-		static void drawStencilRegion(boolean first) {
+		static void drawStencilRegion(boolean first, int mode) {
 
 			// disable drawing to color buffer
 			GL.glColorMask(false, false, false, false);
@@ -373,6 +373,21 @@ public final class PolygonLayer extends RenderElement {
 			GL.glStencilMask(0xFF);
 
 			if (first) {
+				// clear previous clip-region from stencil buffer
+				//GL.glClear(GL20.GL_STENCIL_BUFFER_BIT);
+
+				// Draw clip-region into depth and stencil buffer
+				// this is used for tile line and polygon layers.
+				// Depth offset is increased for each tile. Together
+				// with depth test (GL_LESS) this ensures to only
+				// draw where no other tile has drawn yet.
+				//GL.glEnable(GL20.GL_POLYGON_OFFSET_FILL);
+				if (mode > 1) {
+					// test GL_LESS and write to depth buffer
+					GLState.test(true, true);
+					GL.glDepthMask(true);
+				}
+
 				// always pass stencil test and set clip bit
 				GL.glStencilFunc(GL20.GL_ALWAYS, CLIP_BIT, 0x00);
 			} else {
@@ -388,6 +403,12 @@ public final class PolygonLayer extends RenderElement {
 			GL.glDrawArrays(GL20.GL_TRIANGLE_STRIP, 0, 4);
 
 			if (first) {
+				if (mode > 1) {
+					// dont modify depth buffer
+					GL.glDepthMask(false);
+					// test only stencil
+					GLState.test(false, true);
+				}
 				GL.glStencilFunc(GL20.GL_EQUAL, CLIP_BIT, CLIP_BIT);
 			}
 		}

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

@@ -369,6 +369,7 @@ public class TileRenderer extends LayerRenderer {
 	// tile twice per frame.
 	private int mDrawSerial = 0;
 	private Matrices mMatrices;
+	private int mClipMode = 0;
 
 	/**
 	 * Draw tiles:
@@ -382,6 +383,16 @@ public class TileRenderer extends LayerRenderer {
 
 		mMatrices = m;
 
+		mClipMode = 1;
+
+		for (int i = 0; i < tileCnt; i++) {
+			MapTile t = tiles[i];
+			if (t.isVisible && t.state != STATE_READY) {
+				mClipMode = 2;
+				break;
+			}
+		}
+
 		/** draw visible tiles */
 		for (int i = 0; i < tileCnt; i++) {
 			MapTile t = tiles[i];
@@ -395,11 +406,18 @@ public class TileRenderer extends LayerRenderer {
 		 * was drawn to depth buffer.
 		 * TODO draw proxies for placeholder
 		 */
-		double scale = pos.getZoomScale();
+		if (mClipMode > 1) {
+			mClipMode = 3;
+			//GL.glClear(GL20.GL_DEPTH_BUFFER_BIT);
 
+			GL.glDepthFunc(GL20.GL_LESS);
+
+			double scale = pos.getZoomScale();
 			for (int i = 0; i < tileCnt; i++) {
 				MapTile t = tiles[i];
-			if (t.isVisible && (t.state != STATE_READY) && (t.holder == null)) {
+				if (t.isVisible
+				        && (t.state != STATE_READY)
+				        && (t.holder == null)) {
 					boolean preferParent = (scale > 1.5)
 					        || (pos.zoomLevel - t.zoomLevel < 0);
 					drawProxyTile(t, pos, true, preferParent);
@@ -409,13 +427,15 @@ public class TileRenderer extends LayerRenderer {
 			/** draw grandparents */
 			for (int i = 0; i < tileCnt; i++) {
 				MapTile t = tiles[i];
-			if (t.isVisible && (t.state != STATE_READY) && (t.holder == null))
+				if (t.isVisible
+				        && (t.state != STATE_READY)
+				        && (t.holder == null))
 					drawProxyTile(t, pos, false, false);
 			}
-
+			GL.glDepthMask(false);
+		}
 		/** make sure stencil buffer write is disabled */
 		GL.glStencilMask(0x00);
-		GL.glDepthMask(false);
 
 		mDrawSerial++;
 		mMatrices = null;
@@ -452,17 +472,18 @@ public class TileRenderer extends LayerRenderer {
 		m.mvp.multiplyLhs(m.viewproj);
 
 		boolean clipped = false;
+		int mode = mClipMode;
 		RenderElement l = t.layers.getBaseLayers();
 
 		while (l != null) {
 			if (l.type == POLYGON) {
-				l = PolygonLayer.Renderer.draw(pos, l, m, !clipped, div, true);
+				l = PolygonLayer.Renderer.draw(pos, l, m, !clipped, div, mode);
 				clipped = true;
 				continue;
 			}
 			if (!clipped) {
 				// draw stencil buffer clip region
-				PolygonLayer.Renderer.draw(pos, null, m, true, div, true);
+				PolygonLayer.Renderer.draw(pos, null, m, true, div, mode);
 				clipped = true;
 			}
 			if (l.type == LINE) {
@@ -484,7 +505,7 @@ public class TileRenderer extends LayerRenderer {
 		l = t.layers.getTextureLayers();
 		while (l != null) {
 			if (!clipped) {
-				PolygonLayer.Renderer.draw(pos, null, m, true, div, true);
+				PolygonLayer.Renderer.draw(pos, null, m, true, div, mode);
 				clipped = true;
 			}
 			if (l.type == BITMAP) {