Update imgproc_canny.cl

Reordering condition checking.

modules/ocl/src/opencl/imgproc_canny.cl

@@ -505,17 +505,12 @@ edgesHysteresisGlobal
     int map_offset
 )
 {
-
     map_step   /= sizeof(*map);
     map_offset /= sizeof(*map);
 
     map += map_offset;
 
-    int gidx = get_global_id(0);
-    int gidy = get_global_id(1);
-
     int lidx = get_local_id(0);
-    int lidy = get_local_id(1);
 
     int grp_idx = get_group_id(0);
     int grp_idy = get_group_id(1);
@@ -536,14 +531,11 @@ edgesHysteresisGlobal
     if(ind < count)
     {
         ushort2 pos = st1[ind];
-        if (pos.x > 0 && pos.x <= cols && pos.y > 0 && pos.y <= rows)
-        {
         if (lidx < 8)
         {
             pos.x += c_dx[lidx];
             pos.y += c_dy[lidx];
-
-                if (map[pos.x + pos.y * map_step] == 1)
+            if (pos.x > 0 && pos.x <= cols && pos.y > 0 && pos.y <= rows && map[pos.x + pos.y * map_step] == 1)
             {
                 map[pos.x + pos.y * map_step] = 2;
 
@@ -559,22 +551,18 @@ edgesHysteresisGlobal
             const int subTaskIdx = lidx >> 3;
             const int portion = min(s_counter, (uint)(get_local_size(0)>> 3));
 
-                pos.x = pos.y = 0;
-
             if (subTaskIdx < portion)
                 pos = s_st[s_counter - 1 - subTaskIdx];
-                barrier(CLK_LOCAL_MEM_FENCE);
 
             if (lidx == 0)
                 s_counter -= portion;
             barrier(CLK_LOCAL_MEM_FENCE);
 
-                if (pos.x > 0 && pos.x <= cols && pos.y > 0 && pos.y <= rows)
+            if (subTaskIdx < portion)
             {
                 pos.x += c_dx[lidx & 7];
                 pos.y += c_dy[lidx & 7];
-
-                    if (map[pos.x + pos.y * map_step] == 1)
+                if (pos.x > 0 && pos.x <= cols && pos.y > 0 && pos.y <= rows && map[pos.x + pos.y * map_step] == 1)
                 {
                     map[pos.x + pos.y * map_step] = 2;
 
@@ -604,7 +592,6 @@ edgesHysteresisGlobal
         }
     }
 }
-}
 #undef stack_size
 
 //Get the edge result. egde type of value 2 will be marked as an edge point and set to 255. Otherwise 0.