async thread for CPU openCV processing

src/ofxRGBVHistogram.hpp

@@ -3,6 +3,7 @@
 
 #include <algorithm>
 #include <functional>
+#include <future>
 
 #include "ofxFastFboReader.h"
 #include "ofxHistogram.h"
@@ -45,6 +46,13 @@ public:
     {
         ofPixels pixels;
         reader_.readToPixels(fbo, pixels);
+        histo_stuff_ = async(launch::async, &ofxRGBVHistogram::perform_in_bg, this, pixels);
+    }
+
+    std::pair<bool, std::string> perform_in_bg(ofPixels pixels)
+    {
+        pthread_setname_np(pthread_self(), "histogram");
+
         rgb_.setFromPixels(pixels);
 
         cvCvtColor(rgb_.getCvImage(), hsv_.getCvImage(), CV_BGR2HSV);
@@ -58,8 +66,11 @@ public:
 
         // the hsv conversion is not cheap; this is a faster way to get a sense of the V
         histogramV = histogramR + histogramG + histogramB;
+        return std::make_pair(true, "allo");
     }
 
+    future<std::pair<bool, std::string>> histo_stuff_;
+
     void draw(int x, int y, int w, int h)
     {
         ofPushMatrix();