According to Dallas PD ... Emmett was approached by 2 suspects while sitting in his car in front of his house around 2:30 AM on Monday. One of the suspects pulled out a gun and an altercation ensued.

Cops say Emmett was gunned down while trying to run away from the suspects ... and he was rushed to a nearby hospital, where he later died.

Emmett -- the 35th pick to the Memphis Grizzlies in the 2004 NBA Draft -- was the 2nd leading scorer in the 3-on-3 league this past season while playing for 3's Company.

"The BIG3 is in a state of shock over the sudden and tragic death of Andre Emmett," the league said in a statement. "Andre was a member of the BIG3 family for two seasons and never without a smile on his face."

"His kindness towards others and easy-going demeanor made him a joy to be around."

Emmett briefly played for the Grizzlies and New Jersey Nets ... and played several years overseas.

Emmett was a star at Texas Tech under Bob Knight ... and was inducted into the school's hall of fame in 2018.

#RIP