fix crash when both mask and downscale_factor are set

[jinhwanlazy]

Splatfacto crashes when mask is exist and num_downscale > 0, because downscale has not been applied to mask.

[jb-ye]

Thanks for the catch. It looks good to me.

May I ask when you found num_downscale > 0 useful? I set it to zero because I didn't observe any benefits of that and the official Inria GS doesn't do it either.

[jinhwanlazy]

I found no big difference in the end results, but it makes first training iterations sigificantly faster. So I think it like, why not?

[jb-ye]

I found no big difference in the end results, but it makes first training iterations sigificantly faster. So I think it like, why not?

Okay, I agree this is a bug to be fixed.

[kerrj]

thanks!