Snippets.cs

        /// <summary>
        /// Spherically interpolates a pair of vectors given a percentage <c>t</c>
        /// </summary>
        /// <param name="end">The End result once t is equal to 1</param>
        /// <param name="t">The percent such that 0 < t < 1 </param>
        /// <remarks>
        /// Adapted from https://gist.github.com/manveru/384873
        /// </remarks>
        public static Vector3 Slerp(this Vector3 source, Vector3 end, float t)
        {
            float Omega = (float)Math.Acos(Vector3.Dot(source, end));
            if (Omega != float.NaN && Omega != 0f)
            {
                float Denom = 1f / (float)Math.Sin(Omega);
                return source * (float)(Math.Sin((1 - t) * Omega) * Denom) +
                    (end * (float)Math.Sin((t * Omega) * Denom));
            }
            else
                return source;
        }
        
        public static void DrawText3D(this SpriteBatch source, GraphicsDevice GD, Matrix View, Matrix Proj, Matrix World, Color C, Vector3 Pos, SpriteFont Font, String Text)
        {
            Vector2 NewPos = new Vector2();

            var projectedPos = GD.Viewport.Project(Pos, Proj, View, World);

            NewPos.X = projectedPos.X;
            NewPos.Y = projectedPos.Y;

            source.DrawString(Font, Text, NewPos, C);
        }