T.I. Shoving Match at Vegas Pool Party Hours Before Floyd Fight

052714_ti_scuffle_launchT.I.'s temper was already revved up just hours before he got into a violent brawl with Floyd Mayweather on the Vegas Strip -- when security at a crowded pool party DENIED his ass ... and it's all caught on video.

Witnesses tell TMZ T.I. had shown up to Liquid -- the pool party at Aria where Nicki Minaj was performing last weekend -- but he tried to side step security with his posse.

0527_fatburger_fight_launch_no_swipeSecurity wasn't having it ... insisting T.I. had to be searched just like the normies entering the party.

The real problem -- we're told the door staff didn't recognize Tip ... and once they did realize it was him they let him right into the event.

But the standoff was intense -- Vegas PD even got involved -- and after watching the video, you'll understand why T.I. had a short fuse when he faced off against Floyd later that night. Pretty nuts.