SANTA CLARA >> Brock Purdy, George Kittle and Fred Warner got paid as 49ers’ cornerstones, and the trickle-down economics already are paying dividends for team chemistry.

“This year, having guys done, getting back to work, to be around guys and just build our culture and standard really from the ground up with all the new guys that we have, it’s been pretty cool,” Purdy said Wednesday after signing the biggest contract in 49ers history. “Everybody has bought in right now. We’re excited to do more team activities.”

The 49ers’ offseason program, which has three weeks left, has gone beyond practices, meetings, film review and weight lifting. About 50 players went on the franchise’s golf junket to Carmel. Some guys hunted down clay pigeons at a shooting range. Some headed to a privately rented movie theater.

“Anytime you get 10 to 15 guys to show up, you’re just building that team chemistry there,” Kittle said at Wednesday night’s Dwight Clark Legacy Series. “And it’s fun just being in the locker room getting to know guys.”

Team bonding is necessary after last season’s 6-11 debacle and this offseason’s roster recalibration.

“The young guys, the older guys, everybody is bringing it right now. It’s just so important we’re around each other a lot doing little, different activities and continuing to build chemistry,” Purdy said. “That’s the stuff that matters, when you get in late in the season and things get tough as a team. You want to be able to know the guy next to you and what he’s about and that he’s going to have your back.”

The 49ers, somewhat uncharacteristically, already brokered contract extensions before summer break for their three most prominent leaders: Purdy (five years, $265 million), Kittle (four years, $76.4 million) and Warner (three years, $63 million).

“Every year there has been someone, yeah, you’d like to get them done and it’s gone on pretty late,” Purdy said. “Whether that’s affected the locker room or not, I’m not really sure and don’t want to just pinpoint something.”

But Purdy isn’t shying away from speaking up the older he gets and the more entrenched he becomes with the 49ers.

“One thing I’ve always seen from Brock this offseason is just his voice is heard significantly more in the building, which I love,” Kittle said. “Whether it’s breaking down the team or talking in the locker room, he’s always kind and nice to everybody, but he’s just more vocal to everybody in a team setting, which is huge.”

Two months ago, the 49ers fractured their roster in half, bidding farewell to eight starters and about a dozen reserves in free agency. Purdy showed up on Day 1 of voluntary workouts last month to lead the growth of a new roster.

“Man, Brock Purdy, what a story, seriously. I’ve been a fan of his since the beginning,” Warner said at the Dwight Clark Legacy event at San Jose’s Hammer Theatre. “… I’m so proud of him. It’s just the beginning for him. Purdy, that’s the man. I love playing with him.”

Purdy, in his afternoon media session at Levi’s Stadium, talked about a “re-energized feeling around the facility.”

Kittle echoed that, adding: “The vibes are elite and immaculate. Everybody is having a good time. There’s so much good energy in the building, because you don’t have that pressure yet of learning a game plan and trying to stay healthy for the game on Sunday.”