Fixed stereoBM for Intel CPU.

modules/calib3d/src/opencl/stereobm.cl

@@ -147,6 +147,7 @@ __kernel void stereoBM(__global const uchar * leftptr, __global const uchar * ri
     __local int best_disp[2];
     __local int best_cost[2];
     best_cost[nthread] = MAX_VAL;
+    barrier(CLK_LOCAL_MEM_FENCE);
 
     short costbuf[wsz];
     int head = 0;
@@ -159,7 +160,7 @@ __kernel void stereoBM(__global const uchar * leftptr, __global const uchar * ri
     int costIdx = calcLocalIdx(lx, ly, d, sizeY);
     cost = costFunc + costIdx;
 
-    short tempcost = 0;
+    int tempcost = 0;
     if(x < cols-wsz2-mindisp && y < rows-wsz2)
     {
         int shift = 1*nthread + cols*(1-nthread);
@@ -186,7 +187,11 @@ __kernel void stereoBM(__global const uchar * leftptr, __global const uchar * ri
     if(nthread==1)
     {
         cost[0] = tempcost;
+#ifndef CPU
         atomic_min(best_cost+nthread, tempcost);
+#else
+        *(best_cost+nthread) = min(*(best_cost+nthread), tempcost);
+#endif
     }
     barrier(CLK_LOCAL_MEM_FENCE);
 
@@ -223,7 +228,11 @@ __kernel void stereoBM(__global const uchar * leftptr, __global const uchar * ri
                     cost[0], cost[1], cost[-1], winsize);
         }
         cost[0] = tempcost;
+#ifndef CPU
         atomic_min(best_cost + nthread, tempcost);
+#else
+        *(best_cost + nthread) = min(*(best_cost + nthread), tempcost);
+#endif
         barrier(CLK_LOCAL_MEM_FENCE);
 
         if(best_cost[nthread] == tempcost)

modules/calib3d/src/stereobm.cpp

@@ -744,8 +744,9 @@ static bool ocl_stereobm( InputArray _left, InputArray _right,
     int wsz2 = wsz/2;
 
     int sizeX = std::max(11, 27 - ocl::Device::getDefault().maxComputeUnits() ), sizeY = sizeX-1, N = ndisp*2;
+    bool is_cpu = cv::ocl::Device::getDefault().type() == cv::ocl::Device::TYPE_CPU;
 
-    ocl::Kernel k("stereoBM", ocl::calib3d::stereobm_oclsrc, cv::format("-D csize=%d -D wsz=%d", (2*sizeY)*ndisp, wsz) );
+    ocl::Kernel k("stereoBM", ocl::calib3d::stereobm_oclsrc, cv::format("-D csize=%d -D wsz=%d%s", (2*sizeY)*ndisp, wsz, is_cpu ? " -D CPU" : ""));
     if(k.empty())
         return false;