JensKrumsieck/ChemSharp

using System.Windows.Media;
using System.Windows.Media.Media3D;
using HelixToolkit.Wpf;

namespace ChemSharp.Molecules.HelixToolkit;

public class Atom3D : ModelVisual3D
{
    public static SolidColorBrush SelectionColor = Brushes.LightGoldenrodYellow;
    private bool _isSelected;

    //start with all true
    private bool _isValid = true;

    public Atom3D(Atom atom)
    {
        var builder = new MeshBuilder();
        builder.AddSphere(atom.Location.ToPoint3D(), atom.CovalentRadius / 200d);
        var brush = new BrushConverter().ConvertFromString(atom.Color) as Brush;
        Atom = atom;
        Content = new GeometryModel3D(builder.ToMesh(), MaterialHelper.CreateMaterial(brush, 0, 0));
    }

    public Atom Atom { get; set; }

    public bool IsSelected
    {
        get => _isSelected;
        set
        {
            _isSelected = value;
            UpdateColor();
        }
    }

    public bool IsValid
    {
        get => _isValid;
        set
        {
            _isValid = value;
            UpdateColor();
        }
    }

    protected virtual void UpdateOpacity(Brush brush) => brush.Opacity = IsValid ? 1 : .25f;

    protected virtual void UpdateColor()
    {
        var brush = new BrushConverter().ConvertFromString(Atom.Color) as Brush;
        UpdateOpacity(brush!);
        ((GeometryModel3D)Content).Material =
            MaterialHelper.CreateMaterial(IsSelected ? SelectionColor : brush, 0, 0);
    }

    public override string ToString() => Atom + (IsSelected ? " SelectedAtom" : "");
}