Get Color

        //Return the current color of the particle.
        private Color GetColor()
        {
            int index = timer * (color.Length - 1) / lifeTime + 1;
            if (color.Length <= index)
            {
                return color[index - 1];
            }
            Color color1 = color[index - 1];
            Color color2 = color[index];
            return Color.Lerp(color1, color2, (float)timer * (color.Length - 1) / lifeTime - index + 1);
        }