fixed many bugs related to Mat::getUMat(), asynchronous kernel execution etc. Also, played a bit with ocl::cvtColor vs cv::cvtColor performance

modules/core/test/test_umat.cpp

@@ -200,3 +200,40 @@ void CV_UMatTest::run( int /* start_from */)
 }
 
 TEST(Core_UMat, base) { CV_UMatTest test; test.safe_run(); }
+
+TEST(Core_UMat, simple)
+{
+    {
+    int a[3] = { 1, 2, 3 };
+    Mat m = Mat(1, 1, CV_32SC3, a);
+    UMat u = m.getUMat(ACCESS_READ);
+    EXPECT_NE((void*)NULL, u.u);
+    }
+
+    {
+    Mat m(10, 10, CV_8UC1), ref;
+    for (int y = 0; y < m.rows; ++y)
+    {
+        uchar * const ptr = m.ptr<uchar>(y);
+        for (int x = 0; x < m.cols; ++x)
+            ptr[x] = x + y * 2;
+    }
+
+    ref = m.clone();
+    Rect r(1, 1, 8, 8);
+    ref(r).setTo(17);
+
+    {
+        UMat um = m(r).getUMat(ACCESS_WRITE);
+        um.setTo(17);
+    }
+
+    double err = norm(m, ref, NORM_INF);
+    if(err > 0)
+    {
+        std::cout << "m: " << m << std::endl;
+        std::cout << "ref: " << ref << std::endl;
+    }
+    EXPECT_EQ(err, 0.);
+    }
+}