Charlie Smoked Cocaine, Critiqued Porn Before 911

Charlie Sheen was smoking cocaine while he critiqued porn on his TV set for hours before the 911 call ... TMZ has learned.

Sources who were present at Charlie's house during his 36-hour party tell us ... after a man delivered a briefcase full of cocaine to the house early Wednesday morning, Charlie pulled out a small green pipe and started smoking cocaine continuously ... for hours.

There are many wild details, but we're told eventually Charlie ended up in his theater room with one of the porn stars with whom he was partying. They watched 3 hours of porn, as Charlie critiqued the action on the screen.

We're told Charlie, who fancies himself as a porn connoisseur, was questioning his companion about angles and body shots. We're told the porn star was "surprised" by the depth of Charlie's knowledge.

UPDATE: The 911 call was reportedly made by Sheen's neighbors -- "Real Housewives of Beverly Hills" stars Dr. Paul Nassif and wife Adrienne Maloof-Nassif ... after the couple received a call from someone in Charlie's house advising them of the situation.

Charlie Partied with 5 Girls Before 911 Call

Charlie Sheen was in the middle of a marathon "party" last night and this morning with 5 women before something went so wrong, he ended up on a stretcher in an ambulance.

As we first reported, Charlie was rushed to the hospital at 7 AM today. He's currently at Cedars-Sinai, sleeping, as doctors wait for test results.

Someone who saw Charlie earlier in the evening tells us he was fine. But things changed dramatically as the evening wore on. We're told the party inside was "wild" and went on for at least 24 hours.

We're told Charlie was suffering intense abdominal pain.

One person at the hospital told TMZ, "It's serious."