0025357: STL writer does not check the given shape for existing triangulation and remeshes shape using BRepMesh in force mode.

StlTransfer.cxx, function StlTransfer::BuildIncrementalMesh(...) fills the StlMesh_Mesh. Before this fix the StlTransfer always force meshing of the passed shape.

Now meshing is completely removed from the StlTransfer. StlWriter can return error status now, for example, if a mesh of the passed shape is empty. In this case file will be not created.

Added test case bugs/xde/bug25357

Avoid the warning on gcc compiler.
Test scripts were modified according to the fix.
     1) bug23192, bug22670, bug23193: removed "isParallel" flag from the command
         arguments. Manually meshing of the shape (as far as meshing was removed
         from STL writer).
     2) bug22898: before the fix writestl always remeshes the shape with a
         deflection, related to the boundery box of the shape. For "hammer" shape
         there is a 38.9076 deflection for mesh. Differences between before writing
         and after reading are dedicated to fact that stl writes triangulation as
         an elements of the spahe (like faces, edges etc.)

src/StlAPI/StlAPI.cdl

@@ -25,12 +25,21 @@ uses
     StlMesh
      
 is 
+	enumeration ErrorStatus is 
+		---Purpose: Set of statuses to indicate a type of the error
+		-- occurred during data retrieving and writing operations.
+		StatusOK,
+		MeshIsEmpty,
+		CannotOpenFile
+
+    end ErrorStatus;
+
     class Writer; 
     class Reader; 
     
     Write(aShape      : in Shape from TopoDS;  
           aFile       : in CString from Standard;
-    	  aAsciiMode  : in Boolean from Standard = Standard_True);
+    	  aAsciiMode  : in Boolean from Standard = Standard_True) returns ErrorStatus from StlAPI;
 	  ---Purpose : Convert and write shape to STL format.
 	  --         file is written in binary if aAsciiMode is False
 	  --         otherwise it is written in Ascii (by default)

src/StlAPI/StlAPI.cxx

@@ -15,13 +15,13 @@
 #include <StlAPI_Writer.hxx>
 #include <StlAPI_Reader.hxx>
 
-void StlAPI::Write(const TopoDS_Shape& aShape,
+StlAPI_ErrorStatus StlAPI::Write(const TopoDS_Shape& aShape,
 		   const Standard_CString aFile,
 		   const Standard_Boolean aAsciiMode) 
 {
   StlAPI_Writer writer;
   writer.ASCIIMode() = aAsciiMode;
-  writer.Write (aShape, aFile);
+  return writer.Write (aShape, aFile);
 }
 
 

src/StlAPI/StlAPI_Writer.cdl

@@ -21,34 +21,12 @@ class Writer from StlAPI
 
 uses
     Shape from TopoDS,
-    Mesh from StlMesh
+    Mesh from StlMesh,
+	ErrorStatus from StlAPI
 is
-    Create;
+	Create;
    	 ---Purpose: Creates a writer object with
-   	 -- default parameters: ASCIIMode, RelativeMode, SetCoefficent,
-   	 -- SetDeflection. These parameters may be modified. 
-
-    SetDeflection(me: in out; aDeflection : in Real from Standard);
-    	---Purpose: Sets the deflection of the meshing algorithm. 
-    	--    Deflection is used, only if relative mode is false
-
-    SetCoefficient(me: in out; aCoefficient : in Real from Standard);
-    	---Purpose: Sets the coeffiecient for computation of deflection through 
-    	--          relative size of shape. Default value = 0.001
-
-    RelativeMode(me: in out) returns Boolean;
-       	---C++: return &
-    	---Purpose: Returns the address to the
-    	-- flag defining the relative mode for writing the file.
-    	-- This address may be used to either read or change the flag.
-    	-- If the mode returns True (default value), the
-    	-- deflection is calculated from the relative size of the
-    	-- shape. If the mode returns False, the user defined deflection is used. 
-    	-- Example
-    	-- Read:
-    	-- Standard_Boolean val = Writer.RelativeMode( );
-    	-- Modify:
-    	-- Writer.RelativeMode( ) = Standard_True; 
+   	 -- default parameters: ASCIIMode.
         
     ASCIIMode(me: in out) returns Boolean;
       	---C++: return &
@@ -61,14 +39,11 @@ is
         
     Write(me         : in out; 
           aShape     : Shape from TopoDS; 
-          aFileName  : CString from Standard; 
-          InParallel : Boolean from Standard = Standard_False);
+          aFileName  : CString from Standard) returns ErrorStatus from StlAPI;
     	---Purpose: Converts a given shape to STL format and writes it to file with a given filename.
+		--- \return the error state.
     
 fields
-    theRelativeMode : Boolean from Standard;
     theASCIIMode    : Boolean from Standard;
-    theDeflection   : Real from Standard;
-    theCoefficient   : Real from Standard;
     theStlMesh      : Mesh from StlMesh;
 end Writer;

src/StlAPI/StlAPI_Writer.cxx

@@ -19,30 +19,10 @@
 #include <BRepBndLib.hxx>
 #include <OSD_Path.hxx>
 
-#define MAX2(X, Y)      (  Abs(X) > Abs(Y)? Abs(X) : Abs(Y) )
-#define MAX3(X, Y, Z)   ( MAX2 ( MAX2(X,Y) , Z) )
-
 StlAPI_Writer::StlAPI_Writer()
 {
   theStlMesh = new StlMesh_Mesh;
   theASCIIMode = Standard_True;
-  theDeflection = 0.01;
-  theRelativeMode = Standard_True;
-  theCoefficient = 0.001;
-}
-
-void StlAPI_Writer::SetDeflection(const Standard_Real aDeflection) 
-{
-  theDeflection = aDeflection;
-}
-void StlAPI_Writer::SetCoefficient(const Standard_Real aCoefficient) 
-{
-  theCoefficient = aCoefficient;
-}
-
-Standard_Boolean& StlAPI_Writer::RelativeMode() 
-{
-  return theRelativeMode;
 }
 
 Standard_Boolean& StlAPI_Writer::ASCIIMode() 
@@ -50,23 +30,26 @@ Standard_Boolean& StlAPI_Writer::ASCIIMode()
   return theASCIIMode;
 }
 
-void StlAPI_Writer::Write(const TopoDS_Shape& theShape, const Standard_CString theFileName, const Standard_Boolean theInParallel) 
+StlAPI_ErrorStatus StlAPI_Writer::Write(const TopoDS_Shape& theShape, const Standard_CString theFileName)
 {
   OSD_Path aFile(theFileName);
-  if (theRelativeMode) {
-    Standard_Real aXmin, aYmin, aZmin, aXmax, aYmax, aZmax;
-    Bnd_Box Total;
-    BRepBndLib::Add(theShape, Total);
-    Total.Get(aXmin, aYmin, aZmin, aXmax, aYmax, aZmax);
-    theDeflection = MAX3(aXmax-aXmin , aYmax-aYmin , aZmax-aZmin)*theCoefficient;
-  }
-  StlTransfer::BuildIncrementalMesh(theShape, theDeflection, theInParallel, theStlMesh);
+  StlTransfer::RetrieveMesh(theShape, theStlMesh);
+
+  if (theStlMesh.IsNull() || theStlMesh->IsEmpty())
+    return StlAPI_MeshIsEmpty;
+
   // Write the built mesh
+  Standard_Boolean wasFileOpened = Standard_False;
   if (theASCIIMode) {
-    RWStl::WriteAscii(theStlMesh, aFile);
+    wasFileOpened = RWStl::WriteAscii(theStlMesh, aFile);
     }  
   else {
-    RWStl::WriteBinary(theStlMesh, aFile);
+    wasFileOpened = RWStl::WriteBinary(theStlMesh, aFile);
     }
+
+  if (!wasFileOpened)
+    return StlAPI_CannotOpenFile;
+
+  return StlAPI_StatusOK;
 }