An open front holster is probably what you're looking for (assuming I understand your question correctly). To get just a fast draw, a zero cant, lower riding, open front holster is excellent. I don't do IDPA or anything, so I can't speak to whether or not it's legal there. I've done law enforcement competitions, though, and it isn't legal in the ones I've been in. So, I guess it depends on how you're competing as to whether or not such a holster is appropriate.
Is English your first language? You've asked a couple of times whether your meaning is clear. That's why I ask.