On the first day of GDC Mobile 2009, EA Mobile game producer Mike Pagano gave a candid but useful lecture on the challenges of porting games to the iPhone, sharing the lessons he and his team learned during the production three recent titles - Yahtzee! Adventures, SimCity and Spore Origins.
Having had their fill of complimentary ham sandwiches and Mediterranean salads, a small army of GDC Mobile attendees filed in to room 134, North Hall immediately after lunch on the conference's opening day. Spirits were high, and Pagano was "full of coffee, and a little bit of water."
The first point that Pagano wanted to hit home was that EA does not see these games as ports, quoting Zach Waibel of development partner Tricky Software: "It's an adaptation, not a port."
"We want something that translates from whatever platform we had previously to a new platform," said Pagano, "but with content that only works on that device." For Spore Origins, Pagano "took the original BREW version, tossed it away, and tried to build it from the ground up" to utilize the iPhone's unique aesthetics and input schemes.
"We prototyped a lot," said Pagano, "and after iteration after iteration, they came with the tilt-based control scheme."
Adapting to the iPhone extends beyond UI and control, and affects game design and length. "When we're looking at mobile games, we see them as shorter experiences," Pagno continued. "We like to take that and expand on it. Spore Origins [for other mobile devices] was originally a two-hour game, and we took it to a five-hour game for the iPhone."
Pagano also revealed the relatively quick development times for his three iPhone projects - Spore Origins was completed in four months, plus one month of QA. Yahtzee! Adventures took an estimated three months, and SimCity, he said, took "I think 92 days, from start to finish."
"That was very fast. We were very tired. Method Solutions did a fantastic job on that."
Another important factor when deciding to adapt a game to the iPhone, Pagano said, was the availability of high-res assets. "We had to redesign a lot of the assets on SimCity because it was built for an older PC," said Pagano. The original SimCity was, of course, a low-resolution sprite-based game - high resolution assets were not available for the port, so a lot of time was spent generating new art.
Control scheme is another factor to keep in mind when adapting a game to the iPhone. At one time Pagano's team was trying to design an adaption of EA's Madden Football franchise. "With Madden there were sixteen interactions we needed to get on the screen, how do we do that?" Pagano asked. Ultimately he had to put the game aside, working on Yahtzee! Adventures instead.
Pagano's biggest hurdle to adapting a game for the iPhone is what he calls "fat fingers" - designing a UI and control scheme that does not allow for players to cover the viewing area with his or her fingers. He sees this as "a big stopping point for developers. It's a huge, huge thing."
Pagano recommends button maps on the bottom of the screen, finger-sized, whenever possible, keeping interface away from the play area. "Apple puts the main interactions on the very bottom of the screen," he said. "When you're unlocking for example, you know you can read what's on top. That's a huge thing, especially when you're designing games."
Obviously this is not always possible, so another suggestion he made is to always have some sense of feedback when a button is pressed. The iPhone's touch screen provides no tactcile feedback, so Pagano stressed that developers should always strive to provide audio and visual feedback when a button press is confirmed.
"If I can hammer one thing home today: feedback, feedback, feedback," said Pagano. "Give it a sound, make sure a button looks like a button."
As far as gestures, Pagano points to Apple's proprietary iPhone software, and further recommends developers look at Google Maps for inspiration on simple, effective gesture input. "We noticed that when we had complex gestures, it felt really cool when you got it, but focus testers did not get it without coaching," he said. "Keep your gestures very very simple."
For accelerometer input, "we did a lot of tuning with this SOB," Pagano said, referring to Spore Origins. Pagano stressed that games using the accelerometer should have a mechanism to allow players to change their zero positions, effectively letting them play in a variety of positions - sitting in bed, leaning over the device, or holding it up.
Early in development, Spore Origins had a touchscreen control scheme. "Where it started to fall down was, again, sausage fingers." Said Pagano. "We made our decision right there to flip to the accelerometer."
"When you choose a control scheme, make sure you make it feel good. Don't implement multiple schemes that are just OK, you want to pick one that feels good."