Bennett Foddy interview – the game changer
His games may make you cry, laugh and scream, but they always keep you coming back for more. We get under the skin of Bennett Foddy to find out what drives him to make the web's most innovative games
THE JOY OF PHYSICS
Foddy may describe QWOP as easy to make, but not all his games were quite such a breeze. PoleRiders took a long time to get right, chiefly due to what makes the game such fun, the incredible elasticity of the pole.
“It’s very hard to debug that kind of physics game. The poles are like a worst-case scenario for video game physics. The way that video game physics works, is every frame it looks to see if, for example, your pole is jutting into the other person’s body, and if it is they move back a little bit, but it doesn’t always know what to do if you have very thin, very small bodies,” he says. “It doesn’t know which way it should move [the body] back, and you get this cascade of errors, it’s very difficult to tune.”
PoleRiders is a superb two-player game, and while it can be frustrating when one player runs straight through another’s body and goes on to score, it does add to the random element. Foddy admits that if he knew how popular PoleRiders was going to be, he would have debugged it some more. This, he says, is part of the joy of putting games online for free: people are less likely to complain if some bugs remain.
“If you tried to put out a PS3 game that had these kinds of physics glitches, people would be very upset. As it’s a Flash game, you can get away with it,” he says.
Foddy evidently has his work cut out, as a version of PoleRiders is in development for the PS3 as part of the Sportsfriends package.
GETTING A GIRP
PoleRiders may have been tricky to program, but GIRP was even harder. In GIRP, much of the challenge revolves around knowing exactly when to flex your character’s muscles, in order to use his momentum to scale the cliff, and getting these muscles to behave correctly had Foddy stumped.
“I was stalled on GIRP for quite some time, as I couldn’t get the inverse dynamics, the code that controls the movement of his arms, to work,” he says.
The problem is made more complicated due to the fact that the climber’s body in GIRP is not anchored to anything, it’s your flailing legs and swinging body that affect the movement of the arms. Finally a programming colleague, Chris Hecker, who is currently making the cerebral spy game SpyParty, suggested Foddy use inverse kinematics.
“For anywhere you define a target, it works out where the bits of the arm should be to look right,” Foddy explains.
You can see this effect in action in the Air Toss Flash game, where a colleague throws you crumpled-up bits of paper and you have to throw them into the bin. The position of the man’s hand is determined by the position of the mouse pointer, and the rest of the arm rearranges itself to suit. A similar principle is used by factory robots to orientate their various joints to get the tool hand into position.
Air Toss uses inverse kinematics for realistic arm movement
