GPU resize became same as CPU implementation

modules/gpu/src/opencv2/gpu/device/filters.hpp

@@ -64,7 +64,7 @@ namespace cv { namespace gpu { namespace device
 
         __device__ __forceinline__ elem_type operator ()(float y, float x) const
         {
-            return src(__float2int_rn(y), __float2int_rn(x));
+            return src(__float2int_rz(y), __float2int_rz(x));
         }
 
         const Ptr2D src;

modules/gpu/test/interpolation.hpp

@@ -54,7 +54,7 @@ template <typename T> struct NearestInterpolator
 {
     static T getValue(const cv::Mat& src, float y, float x, int c, int border_type, cv::Scalar borderVal = cv::Scalar())
     {
-        return readVal<T>(src, cvRound(y), cvRound(x), c, border_type, borderVal);
+        return readVal<T>(src, int(y), int(x), c, border_type, borderVal);
     }
 };
 

modules/gpu/test/test_resize.cpp

@@ -160,7 +160,7 @@ INSTANTIATE_TEST_CASE_P(GPU_ImgProc, Resize, testing::Combine(
 
 
 /////////////////
-PARAM_TEST_CASE(ResizeArea, cv::gpu::DeviceInfo, cv::Size, MatType, double, Interpolation, UseRoi)
+PARAM_TEST_CASE(ResizeSameAsHost, cv::gpu::DeviceInfo, cv::Size, MatType, double, Interpolation, UseRoi)
 {
     cv::gpu::DeviceInfo devInfo;
     cv::Size size;
@@ -182,6 +182,28 @@ PARAM_TEST_CASE(ResizeArea, cv::gpu::DeviceInfo, cv::Size, MatType, double, Inte
     }
 };
 
+// downscaling only: used for classifiers
+TEST_P(ResizeSameAsHost, Accuracy)
+{
+    cv::Mat src = randomMat(size, type);
+
+    cv::gpu::GpuMat dst = createMat(cv::Size(cv::saturate_cast<int>(src.cols * coeff), cv::saturate_cast<int>(src.rows * coeff)), type, useRoi);
+    cv::gpu::resize(loadMat(src, useRoi), dst, cv::Size(), coeff, coeff, interpolation);
+
+    cv::Mat dst_gold;
+    cv::resize(src, dst_gold, cv::Size(), coeff, coeff, interpolation);
+
+    EXPECT_MAT_NEAR(dst_gold, dst, src.depth() == CV_32F ? 1e-2 : 1.0);
+}
+
+INSTANTIATE_TEST_CASE_P(GPU_ImgProc, ResizeSameAsHost, testing::Combine(
+    ALL_DEVICES,
+    DIFFERENT_SIZES,
+    testing::Values(MatType(CV_8UC3), MatType(CV_16UC1), MatType(CV_16UC3), MatType(CV_16UC4), MatType(CV_32FC1), MatType(CV_32FC3), MatType(CV_32FC4)),
+    testing::Values(0.3, 0.5),
+    testing::Values(Interpolation(cv::INTER_AREA), Interpolation(cv::INTER_NEAREST)),  //, Interpolation(cv::INTER_LINEAR), Interpolation(cv::INTER_CUBIC)
+    WHOLE_SUBMAT));
+
 ///////////////////////////////////////////////////////////////////
 // Test NPP