Spec color and intensity on the same map is usually a little easier to work with, but it can lead to problems if you need a high spec value that's not white. Having the ability to use a spec intensity and spec color map or a combined intensity/color map with a radio button to select what you're using would be the best bet.…
the spec color and spec intensity can be the same map--that will leave you with less textures overall, and the information for intensity is pretty much the same as a color value, really. Instead of a separate map that drives intensity all you really need is a single float value (specular strength) that sets what max…
With game dev the advantage of using a greyscale spec map is that we can stick it in the alpha channel of some texture. The diffuse, or sometimes the normal map even. But if we need specular color, then we need a whole new RGB texture anyway, so it doesn't make sense in that case to still use the alpha channel of the…