Support layer opacity for vector points

Author: ahocevar

src/core.js

@@ -412,6 +412,30 @@ goog.require('olcs.core.OlLayerPrimitive');
   };
 
 
+  /**
+   * Synchronizes the vector layer rendering properties (currently only
+   * 'opacity') to the given Cesium primitives.
+   * @param {!ol.layer.Vector} olLayer
+   * @param {!Cesium.PrimitiveCollection} csPrimitives
+   * @api
+   */
+  olcs.core.updateCesiumPrimitives = function(olLayer, csPrimitives) {
+    //FIXME Make this work for all geometry types, not just points
+    var bbs = csPrimitives.context.billboards;
+    var opacity = olLayer.getOpacity();
+    if (!goog.isDef(opacity)) {
+      opacity = 1;
+    }
+    bbs.olLayerOpacity = opacity;
+    var i, bb;
+    for (i = bbs.length - 1; i >= 0; --i) {
+      bb = bbs.get(i);
+      //FIXME Use Cesium.Color.fromAlpha after the next Cesium update
+      bb.color = new Cesium.Color(1.0, 1.0, 1.0, bb.olStyleOpacity * opacity);
+    }
+  };
+
+
   /**
    * Convert a 2D or 3D OpenLayers coordinate to Cesium.
    * @param {ol.Coordinate} coordinate Ol3 coordinate.
@@ -789,16 +813,20 @@ goog.require('olcs.core.OlLayerPrimitive');
       var position = olcs.core.ol4326CoordinateToCesiumCartesian(center);
       var color;
       var opacity = imageStyle.getOpacity();
-      if (goog.isDef(opacity)) {
-        color = new Cesium.Color(1.0, 1.0, 1.0, opacity);
+      if (!goog.isDef(opacity)) {
+        opacity = 1;
       }
+      //FIXME Use Cesium.Color.fromAlpha after the next Cesium update
+      color = new Cesium.Color(1.0, 1.0, 1.0,
+          opacity * billboards.olLayerOpacity);
       var bb = billboards.add({
         // always update Cesium externs before adding a property
         image: image,
         color: color,
         verticalOrigin: Cesium.VerticalOrigin.BOTTOM,
         position: position
       });
+      bb.olStyleOpacity = opacity;
       if (opt_newBillboardCallback) {
         opt_newBillboardCallback(bb);
       }

src/vectorsynchronizer.js

@@ -81,6 +81,11 @@ olcs.VectorSynchronizer.prototype.createSingleCounterpart = function(olLayer) {
     csPrimitives.show = olLayer.getVisible();
   });
 
+  olLayer.on('change:opacity', function(e) {
+    olcs.core.updateCesiumPrimitives(olLayer, csPrimitives);
+  });
+  olcs.core.updateCesiumPrimitives(olLayer, csPrimitives);
+
   var onAddFeature = function(feature) {
     goog.asserts.assertInstanceof(olLayer, ol.layer.Vector);
     var prim = csPrimitives.convert(olLayer, view, feature);