added taking 3D board snapshots

examples/browser/control.html

@@ -30,6 +30,7 @@
 	       		<button id="save">Save</button>
 				<input type="file" id="fileElem" accept="application/json" style="display:none"/>
 	       		<button id="load">Load</button>
+	       		<button id="snapshot">Snapshot</button>
                 <br/><br/>
 	       		<select id="mode">
 	       			<option value="self-self">Self / Self</option>

examples/browser/js/control.js

@@ -278,6 +278,19 @@ $(document).ready(function () {
                         });
                 });
 
+				$("#snapshot").on("click",function() {
+					match.viewControl("takeSnapshot")
+						.then((snapshot)=>{
+							var a = document.createElement("a");
+							a.href = snapshot;
+							a.setAttribute("download",gameName+".png");
+							a.click();
+						})
+						.catch((error)=>{
+							console.warn("failed:",error);
+						})
+				});
+
                 // reading file locally
                 var fileElem = $("#fileElem").on("change",function() {
                     var fileReader = new FileReader();

src/browser/jocly.xd-view.js

@@ -2771,6 +2771,15 @@ if(window.JoclyXdViewCleanup)
 						});					
 						xdv.removeGadget("panorama");
 					}
+					resolve();
+					break;
+				case "takeSnapshot":
+					if(threeCtx) {
+						var canvas = threeCtx.renderer.domElement;
+						threeCtx.renderer.render( threeCtx.scene, threeCtx.camera );
+						resolve(canvas.toDataURL("image/png"));
+					} else
+						reject(new Error("Snapshot only available on 3D views"));
 					break;
 		
 				default: