Use the covariant return type feature of C# 9 to allow method overrides to be more specific about their return type. By exposing this information, e.g. for Widget.Clone(), callers will have more information. This allows various casts to be removed as the information is now available within the type system.
Callers can provide 3D points easily, and this avoids the need to allocate and slow down enumeration via the points.Select(p => new float3(p, 0)) wrapper.
- Create an overload that renders a line in one color, as this allows most existing calls to be simplified. This also allows a slight performance improvement by only normalizing the components once.
- Introduce a DrawLineStrip method. This improves performance by allowing the color components to be normalized once for the whole strip, and only needing to calculate vertices once per point rather than twice since we can reuse the last result.
