simple update

examples/common.js

@@ -107,10 +107,7 @@ class XRExampleBase {
 			this.session.addEventListener('blur', ev => { this.handleSessionBlur(ev) })
 			this.session.addEventListener('end', ev => { this.handleSessionEnded(ev) })
 
-			// if this session is getting video frames, lets set up a callback.
-			// EVENTUALLY should look at properties on the session to see if user 
-			// approved it, but the app doesn't let us know this yet
-			this.session.requestVideoFrames(ev => { this.handleVideoFrame(ev) })
+			this.newSession();
 
 			if(this.shouldStartPresenting){
 				// VR Displays need startPresenting called due to input events like a click
@@ -122,6 +119,11 @@ class XRExampleBase {
 		})
 	}
 
+	/*
+	  Clients should override to be called when a new session is created
+	  */
+	newSession() {}
+
 	/*
 		Empties this.el, adds a div with the message text, and shows a button to test rendering the scene to this.el
 	*/
@@ -167,7 +169,18 @@ class XRExampleBase {
 	handleLayerFocus(ev){}
 	handleLayerBlur(ev){}
 
-	handleVideoFrame(ev){}
+	/*
+	* set up the video processing
+	*/
+	setVideoWorker(worker){
+		//
+		// NOTE:  not a worker, a callback!  Couldn't get workers working!
+		//
+		// if this session is getting video frames, lets set up a callback.
+		// EVENTUALLY should look at properties on the session to see if user 
+		// approved it, but the app doesn't let us know this yet
+		this.session.requestVideoFrames(worker)
+	}
 
 	/*
 	Extending classes should override this to set up the scene during class construction

examples/simplecv/index.html

@@ -68,6 +68,10 @@
 					this.el.appendChild(this.textBox)
 				}
 
+				newSession() {
+					this.setVideoWorker(ev => { this.handleVideoFrame(ev) })
+				}
+
 				// Called during construction
 				initializeScene(){
 					// Add a box at the scene origin
@@ -121,7 +125,7 @@
 					var camera = ev.detail.camera
 					switch (frame.pixelFormat) {
 						case "YUV420P":
-							this.averageIntensity(frame.buffers[0])
+						this.averageIntensity(frame.buffers[0])
 					}
 				}
 

examples/simplecv/intensity.js

@@ -0,0 +1,38 @@
+// could not get workers working, so am not using this.
+//
+// Tried to use Transferable ArrayBuffers but kept getting DOM Error 25. 
+// 
+
+
+averageIntensity = function (buffer) {
+    var w = buffer.size.width;
+    var h = buffer.size.height;
+    var pad = buffer.size.bytesPerRow - w;
+    var pixels = buffer.buffer;
+
+    var intensity = 0.0;
+    var p = 0;
+    for (var r = 0; r < h; r++) {
+        var v = 0;
+        for (var i = 0; i < w; i++) {
+            if (p < pixels.length) {
+                v += pixels[p++]
+            } else {
+                console.error("overflow pixel buffer")
+            }
+        }
+        intensity += v / w;
+        p += pad;
+    }
+
+    postMessage ((intensity / h) / 255.0);
+}
+
+onMessage = function (ev) {
+    var frame = ev.detail.frame
+    var camera = ev.detail.camera
+    switch (frame.pixelFormat) {
+        case "YUV420P":
+    	this.averageIntensity(frame.buffers[0])
+    }
+}