3D view: honor round rectangle shape.

Fixes https://gitlab.com/kicad/code/kicad/-/issues/21597

3d-viewer/3d_canvas/create_3Dgraphic_brd_items.cpp

@@ -47,6 +47,7 @@
 #include <geometry/shape_segment.h>
 #include <geometry/geometry_utils.h>
 #include <geometry/shape_circle.h>
+#include <geometry/roundrect.h>
 #include <geometry/shape_rect.h>
 #include <geometry/shape_simple.h>
 #include <utility>
@@ -648,6 +649,26 @@ void BOARD_ADAPTER::addShape( const PCB_SHAPE* aShape, CONTAINER_2D_BASE* aConta
                 ConvertPolygonToTriangles( polyList, *aContainer, m_biuTo3Dunits, *aOwner );
             }
             else
+            {
+                if( aShape->GetCornerRadius() > 0 )
+                {
+                    ROUNDRECT rr( SHAPE_RECT( aShape->GetPosition(),
+                                              aShape->GetRectangleWidth(),
+                                              aShape->GetRectangleHeight() ),
+                                              aShape->GetCornerRadius() );
+                    SHAPE_POLY_SET poly;
+                    rr.TransformToPolygon( poly );
+                    SHAPE_LINE_CHAIN& r_outline = poly.Outline( 0 );
+                    r_outline.SetClosed( true );
+
+                    for( int ii = 0; ii < r_outline.PointCount(); ii++ )
+                    {
+                        addROUND_SEGMENT_2D( aContainer, TO_SFVEC2F( r_outline.CPoint( ii ) ),
+                                             TO_SFVEC2F( r_outline.CPoint( ii+1 ) ),
+                                             linewidth3DU, *aOwner );
+                    }
+                }
+                else
                 {
                     std::vector<VECTOR2I> pts = aShape->GetRectCorners();
 
@@ -660,6 +681,7 @@ void BOARD_ADAPTER::addShape( const PCB_SHAPE* aShape, CONTAINER_2D_BASE* aConta
                     addROUND_SEGMENT_2D( aContainer, TO_SFVEC2F( pts[3] ), TO_SFVEC2F( pts[0] ),
                                          linewidth3DU, *aOwner );
                 }
+            }
             break;
 
         case SHAPE_T::ARC: