an orthographic camera example for FNA

OrthographicCamera.cs

public struct OrthographicCamera : ICamera
{
    public Matrix View { get; }
    public Matrix Projection { get; }

    public Vector3 Position { get; }
    public Vector3 Forward { get; }
    public Vector3 Up { get; }
    public Vector3 Right { get; }

    public float Width { get; }
    public float Height { get; }
    public float NearPlane { get; }
    public float FarPlane { get; }

    public OrthographicCamera(
        Vector3 position,
        Vector3 forward,
        Vector3 up,
        float width,
        float height,
        float nearPlane,
        float farPlane
    ) {
        Position = position;
        Forward = forward;
        Up = up;
        Right = Vector3.Cross(forward, up);
        View = Matrix.CreateLookAt(Position, Position + Forward, Up);

        Width = width;
        Height = height;
        NearPlane = nearPlane;
        FarPlane = farPlane;

        Projection = Matrix.CreateOrthographicOffCenter(
            0,
            Width,
            Height,
            0,
            nearPlane,
            farPlane
        );
    }
}