Add depth test to PolygonReplay

src/ol/render/webgl/polygonreplay/index.js

@@ -870,6 +870,16 @@ ol.render.webgl.PolygonReplay.prototype.shutDownProgram = function(gl, locations
  * @inheritDoc
  */
 ol.render.webgl.PolygonReplay.prototype.drawReplay = function(gl, context, skippedFeaturesHash, hitDetection) {
+  //Save GL parameters.
+  var tmpDepthFunc = /** @type {number} */ (gl.getParameter(gl.DEPTH_FUNC));
+  var tmpDepthMask = /** @type {boolean} */ (gl.getParameter(gl.DEPTH_WRITEMASK));
+
+  if (!hitDetection) {
+    gl.enable(gl.DEPTH_TEST);
+    gl.depthMask(true);
+    gl.depthFunc(gl.NOTEQUAL);
+  }
+
   if (!ol.obj.isEmpty(skippedFeaturesHash)) {
     this.drawReplaySkipping_(gl, context, skippedFeaturesHash);
   } else {
@@ -887,6 +897,13 @@ ol.render.webgl.PolygonReplay.prototype.drawReplay = function(gl, context, skipp
       end = start;
     }
   }
+  if (!hitDetection) {
+    gl.disable(gl.DEPTH_TEST);
+    gl.clear(gl.DEPTH_BUFFER_BIT);
+    //Restore GL parameters.
+    gl.depthMask(tmpDepthMask);
+    gl.depthFunc(tmpDepthFunc);
+  }
 };
 
 
@@ -964,6 +981,7 @@ ol.render.webgl.PolygonReplay.prototype.drawReplaySkipping_ = function(gl, conte
       if (skippedFeaturesHash[featureUid]) {
         if (start !== end) {
           this.drawElements(gl, context, start, end);
+          gl.clear(gl.DEPTH_BUFFER_BIT);
         }
         end = featureStart;
       }
@@ -972,6 +990,7 @@ ol.render.webgl.PolygonReplay.prototype.drawReplaySkipping_ = function(gl, conte
     }
     if (start !== end) {
       this.drawElements(gl, context, start, end);
+      gl.clear(gl.DEPTH_BUFFER_BIT);
     }
     start = end = groupStart;
   }

test/spec/ol/render/webgl/polygonreplay.test.js

@@ -406,7 +406,14 @@ describe('ol.render.webgl.PolygonReplay', function() {
       geometry: new ol.geom.Polygon([[[0, 0], [500, 500], [500, 0], [0, 0]]])
     });
     beforeEach(function() {
-      gl = {};
+      gl = {
+        getParameter: function() {},
+        enable: function() {},
+        disable: function() {},
+        depthMask: function() {},
+        depthFunc: function() {},
+        clear: function() {}
+      };
       context = {};
       replay.setFillStyle_ = function() {};
       replay.drawElements = function() {};