--- a/tests/efu.c	Thu May 10 04:36:03 2018 +0300
+++ b/tests/efu.c	Thu May 10 04:39:34 2018 +0300
@@ -276,6 +276,36 @@
         }
 }
 
+#define Q_KERNEL(x, y, dist, coeff) ( \
+        in[(y) - (dist)][(x)] * (coeff) + \
+        in[(y) + (dist)][(x)] * (coeff) + \
+        in[(y)][(x) - (dist)] * (coeff) + \
+        in[(y)][(x) + (dist)] * (coeff) + \
+        in[(y) - (dist)][(x) - (2)] * (coeff) + \
+        in[(y) - (dist)][(x) + (2)] * (coeff) + \
+        in[(y) + (dist)][(x) - (2)] * (coeff) + \
+        in[(y) + (dist)][(x) + (2)] * (coeff))
+
+#define Q_VALUES(coeff) (8 * (coeff))
+
+void dmSmoothMap(DMBlockMap out, DMBlockMap in)
+{
+    int x, y;
+
+    for (y = 0; y < QHEIGHT; y++)
+    for (x = 0; x < QWIDTH; x++)
+    {
+        if (y >= 3 && x >= 3 && y < QHEIGHT - 3 && x < QWIDTH - 3)
+            out[y][x] = (
+                Q_KERNEL(x, y, 3, 1) +
+                Q_KERNEL(x, y, 2, 2) +
+                Q_KERNEL(x, y, 1, 4) +
+                in[y][x] * 16) /
+                (16 + Q_VALUES(1) + Q_VALUES(2) + Q_VALUES(4));
+        else
+            out[y][x] = in[y][x];
+    }
+}
 
 int main(int argc, char *argv[])
 {