sneak attack = normal attack + [ (0.5*level) rounded up ] D6
Ex : rogue lvl 5 (14 DEX) with dagger deals : 1D4 + 2 + 3D6
That is the way it should be handled, but it currently is not I checked when I was playing rogue during the alpha the litteral equation they were using to determine sneak attack damage is 1d6 * ((Level - 1)/2 + 1)
Additionally they are currently treating it as a second attack breaking the game in many aspects.
For example if at level 4 you take Warlock magic initiate for Hex and you will deal 1d6 on you normal hit, and an additonal 1d6 on the sneak hit.
This also applies to GWM +10 damage, if you sneak attack with a heavy weapon it will actually deal +20 damage.
