Visualizing Triangulations

OK. OK. Then its very easy, do it like this:

Create your own InteractiveObject, that inherits from AIS_InteractiveObject for example "MyPack_Triangulation". Redefine the Compute method and get the structure manager from the given PresentationManager. Define as a member a Graphic3d_Group (here: myGroup). Fill the group with your triangulation and stick it into the given Presentation. Assuming that you have the following members:

myTriangles : HArray1OfTriangle from Poly;

myGroup : Group from Graphic3d;

myNodes : HArray1OfPnt from TColgp;

myD1u : HArray1OfXYZ from TColgp;

myD1v : HArray1OfXYZ from TColgp;

Then it could look like:

void MyPack_Triangulation::Compute(const Handle_PrsMgr_PresentationManager3d& aPresentationManager,const Handle_Prs3d_Presentation& aPresentation,const Standard_Integer aMode)

{

Handle_Graphic3d_StructureManager aViewer = aPresentationManager->StructureManager();

// first remove all groups out of this presentation

Prs3d_Root::CurrentGroup(aPresentation)->Remove();

if (!myGroup.IsNull())

myGroup->Remove();

// set the aspect for the presentation of the triangulation depending on the mode

switch (aMode)

{

case 1: myDrawer->ShadingAspect()->Aspect()->SetInteriorStyle(Aspect_IS_SOLID); break;

case 2: myDrawer->ShadingAspect()->Aspect()->SetInteriorStyle(Aspect_IS_HOLLOW); break;

case 3: myDrawer->ShadingAspect()->Aspect()->SetInteriorStyle(Aspect_IS_EMPTY); break;

}

///// Normal shaded, triangulated or empty presentation

if (aMode<4)

{

myCurvat.Nullify(); // delete curvature values, if we changed to another mode

myInterp.Nullify(); // delete interpolator, if we changed to another mode

aPresentation->SetShadingAspect(myDrawer->ShadingAspect());

// clear the groups in the presentation ...

aPresentation->Clear(Standard_False);

myGroup = new Graphic3d_Group(aPresentation);

// dMode=3 is an empty presentation --> we need not to compute the visualization

if (dMode==3)

return;

}

else

return;

// Set the triangles first

Standard_Integer i, lower=myTriangles->Lower(), upper=myTriangles->Upper()+1;

Aspect_Array1OfEdge arrayEdgS (1, 3*myTriangles->Length());

Aspect_TypeOfEdge theEType = Aspect_TOE_INVISIBLE;

for (i=lower; iValue(i).Get(I,J,K);

arrayEdgS(3*i-2).SetValues(I,J,theEType);

arrayEdgS(3*i-1).SetValues(J,K,theEType);

arrayEdgS(3*i).SetValues(K,I,theEType);

}

// Set the Nodes and the normals if we have some and finally set the group

lower=myNodes->Lower(), upper=myNodes->Upper()+1;

// Check if we have normals. If not, we have to use Graphic3d_Array1OfVertex

// instead of an array of Graphic3d_Array1OfVertexN.

if (myD1u.IsNull() || myD1v.IsNull())

{

Graphic3d_Array1OfVertex arrayVertX (1, myNodes->Length());

for (i=lower; iValue(i).X(), myNodes->Value(i).Y(), myNodes->Value(i).Z());

myGroup->TriangleSet(arrayVertX,arrayEdgS);

}

else

{

Graphic3d_Array1OfVertexN arrayVertXN (1, myNodes->Length());

for (i=lower; iValue(i) ^ myD1v->Value(i);

arrayVertXN(i).SetCoord(myNodes->Value(i).X(), myNodes->Value(i).Y(), myNodes->Value(i).Z());

arrayVertXN(i).SetNormal(nrm.X(), nrm.Y(), nrm.Z());

}

myGroup->TriangleSet(arrayVertXN,arrayEdgS);

}

}

Best regards,

Michael

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University of Kaiserslautern

Research Group for Computer Application in Engineering Design

http://rkk.mv.uni-kl.de

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