0025463: Visualization - MeshVS_ElementalColorPrsBuilder produces inefficient structures for elements with unique colors

Create array with per-node color assigned

src/MeshVS/MeshVS_ElementalColorPrsBuilder.cxx

@@ -245,7 +245,58 @@ void MeshVS_ElementalColorPrsBuilder::Build ( const Handle(Prs3d_Presentation)&
   }
 
   // Draw elements with one color
-  for ( MeshVS_DataMapIteratorOfDataMapOfColorMapOfInteger aColIter ( aColorsOfElements ); aColIter.More();
+  Standard_Integer aNbFacePrimitives = 0;
+  for (it.Reset(); it.More(); it.Next())
+  {
+    if (!anElemColorMap->IsBound (it.Key()))
+      continue;
+
+    Standard_Integer aNbNodes = 0;
+    if (!aSource->GetGeom (it.Key(), Standard_True, aCoords, aNbNodes, aType))
+      continue;
+
+    if (aType == MeshVS_ET_Face)
+    {
+      aNbFacePrimitives += aNbNodes - 2; // add face triangles
+    }
+  }
+
+  Handle(Graphic3d_ArrayOfTriangles) aTriangles = new Graphic3d_ArrayOfTriangles (aNbFacePrimitives * 3, 0, Standard_False, Standard_True);
+  for (it.Reset(); it.More(); it.Next())
+  {
+    if (!anElemColorMap->IsBound (it.Key()))
+      continue;
+
+    Standard_Integer aNbNodes = 0;
+    if (!aSource->GetGeom (it.Key(), Standard_True, aCoords, aNbNodes, aType))
+      continue;
+
+    const Quantity_Color& aColor = anElemColorMap->Find (it.Key());
+    if (aType == MeshVS_ET_Face)
+    {
+      for (Standard_Integer aNodeIdx = 0; aNodeIdx < aNbNodes - 2; ++aNodeIdx)
+      {
+        for (Standard_Integer anIdx = 0; anIdx < 3; ++anIdx)
+        {
+          aTriangles->AddVertex (gp_Pnt (aCoords (3 * (anIdx == 0 ? 0 : (aNodeIdx + anIdx)) + 1),
+                                         aCoords (3 * (anIdx == 0 ? 0 : (aNodeIdx + anIdx)) + 2),
+                                         aCoords (3 * (anIdx == 0 ? 0 : (aNodeIdx + anIdx)) + 3)),
+                                 aColor);
+
+        }
+      }
+    }
+  }
+  Handle(Graphic3d_Group) aTrisGroup = Prs3d_Root::NewGroup (Prs);
+
+  Handle(Graphic3d_AspectFillArea3d) aFillAspect = new Graphic3d_AspectFillArea3d (Aspect_IS_SOLID, Quantity_NOC_WHITE, anEdgeColor,
+                                                                                   anEdgeType, anEdgeWidth, aMaterial[0], aMaterial[1]);
+  aFillAspect->SetDistinguishOff();
+  aFillAspect->SetEdgeOff();
+  aTrisGroup->SetGroupPrimitivesAspect (aFillAspect);
+  aTrisGroup->AddPrimitiveArray (aTriangles);
+
+  /**for ( MeshVS_DataMapIteratorOfDataMapOfColorMapOfInteger aColIter ( aColorsOfElements ); aColIter.More();
         aColIter.Next() )
   {
     Standard_Integer aSize = aColIter.Value().Extent();
@@ -254,12 +305,9 @@ void MeshVS_ElementalColorPrsBuilder::Build ( const Handle(Prs3d_Presentation)&
 
     TColStd_PackedMapOfInteger aCustomElements;
 
-    Prs3d_Root::NewGroup ( Prs );
+    Handle(Graphic3d_Group) aGGroup = Prs3d_Root::NewGroup (Prs);
-    Handle ( Graphic3d_Group ) aGGroup = Prs3d_Root::CurrentGroup ( Prs );
+    Handle(Graphic3d_Group) aLGroup = Prs3d_Root::NewGroup (Prs);
-    Prs3d_Root::NewGroup ( Prs );
+    Handle(Graphic3d_Group) aSGroup = Prs3d_Root::NewGroup (Prs);
-    Handle ( Graphic3d_Group ) aLGroup = Prs3d_Root::CurrentGroup ( Prs );
-    Prs3d_Root::NewGroup ( Prs );
-    Handle ( Graphic3d_Group ) aSGroup = Prs3d_Root::CurrentGroup ( Prs );
 
     Standard_Integer aNbFacePrimitives = 0;
     Standard_Integer aNbVolmPrimitives = 0;
@@ -316,8 +364,7 @@ void MeshVS_ElementalColorPrsBuilder::Build ( const Handle(Prs3d_Presentation)&
     // cell rendering (normal interpolation is not always applicable - flat shading),
     // elemental coloring (color interpolation is impossible)
 
-    Handle (Graphic3d_ArrayOfTriangles) aFaceTriangles = new Graphic3d_ArrayOfTriangles (
+    Handle(Graphic3d_ArrayOfTriangles) aFaceTriangles = new Graphic3d_ArrayOfTriangles ((aNbFacePrimitives + aNbVolmPrimitives) * 3, 0, IsReflect);
-     (aNbFacePrimitives + aNbVolmPrimitives) * 3, 0, IsReflect );
     Standard_Boolean IsPolyG = Standard_False;
 
     Handle (Graphic3d_ArrayOfSegments) anEdgeSegments = new Graphic3d_ArrayOfSegments (aNbEdgePrimitives * 2);
@@ -640,7 +687,7 @@ void MeshVS_ElementalColorPrsBuilder::Build ( const Handle(Prs3d_Presentation)&
     aGroup2->SetGroupPrimitivesAspect (anAsp);
     aGroup3->AddPrimitiveArray (anEdgeSegments);
     aGroup3->SetGroupPrimitivesAspect (anEdgeAspect);
-  }
+  }*/
 }
 
 //================================================================