Using Accelerometer for Sprite Movement

via: http://www.cocos2d-iphone.org/wiki/doku.php/tips:using_accelerometer_for_sprite_movement

init{

self.isAccelerometerEnabled = YES;

[[UIAccelerometer sharedAccelerometer] setUpdateInterval:1/60];

}

#define kHeroMovementAction 1
#define kPlayerSpeed 100
- (void) accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration {
    // use the running scene to grab the appropriate game layer by it's tag
    GameLayer *layer = (GameLayer *)[[[CCDirector sharedDirector] runningScene] getChildByTag:kTagGameLayer];
    // grab the player sprite from that layer using it's tag
    CCSprite *playerSprite = (CCSprite *)[layer getChildByTag:kTagSpritePlayer];
    float destX, destY;
    BOOL shouldMove = NO;
 
    float currentX = playerSprite.position.x;
    float currentY = playerSprite.position.y;
 
    if(acceleration.x > 0.25) {  // tilting the device upwards
        destX = currentX - (acceleration.y * kPlayerSpeed);
        destY = currentY + (acceleration.x * kPlayerSpeed);
        shouldMove = YES;
    } else if (acceleration.x < -0.25) {  // tilting the device downwards
        destX = currentX - (acceleration.y * kPlayerSpeed);
        destY = currentY + (acceleration.x * kPlayerSpeed);
        shouldMove = YES;
    } else if(acceleration.y < -0.25) {  // tilting the device to the right
        destX = currentX - (acceleration.y * kPlayerSpeed);
        destY = currentY + (acceleration.x * kPlayerSpeed);
        shouldMove = YES;
    } else if (acceleration.y > 0.25) {  // tilting the device to the left
        destX = currentX - (acceleration.y * kPlayerSpeed);
        destY = currentY + (acceleration.x * kPlayerSpeed);
        shouldMove = YES;
    } else {
        destX = currentX;
        destY = currentY;
    }
 
    if(shouldMove) {
        CGSize wins = [[CCDirector sharedDirector] winSize];
        // ensure we aren't moving out of bounds     
        if(destX < 30 || destX > wins.width - 30 || destY < 30 || destY > wins.height - 100) {
            // do nothing
        } else {
            CCAction *action = [CCMoveTo actionWithDuration:1 position: CGPointMake(destX, destY)];
            [action setTag:kHeroMovementAction];
            [playerSprite runAction:action];
        }
    } else {
        // should stop
        [playerSprite stopActionByTag:kHeroMovementAction];
    }
 
}