Merge pull request #1091 from Aldert/patch-1

Update motion_control.cpp

Marlin/motion_control.cpp

@@ -44,6 +44,14 @@ void mc_arc(float *position, float *target, float *offset, uint8_t axis_0, uint8
   if (angular_travel < 0) { angular_travel += 2*M_PI; }
   if (isclockwise) { angular_travel -= 2*M_PI; }
   
+  //20141002:full circle for G03 did not work, e.g. G03 X80 Y80 I20 J0 F2000 is giving an Angle of zero so head is not moving
+  //to compensate when start pos = target pos && angle is zero -> angle = 2Pi
+  if (position[axis_0] == target[axis_0] && position[axis_1] == target[axis_1] && angular_travel == 0)
+  {
+	  angular_travel += 2*M_PI;
+  }
+  //end fix G03
+  
   float millimeters_of_travel = hypot(angular_travel*radius, fabs(linear_travel));
   if (millimeters_of_travel < 0.001) { return; }
   uint16_t segments = floor(millimeters_of_travel/MM_PER_ARC_SEGMENT);