How to slice/cut sprites in iOS (Core Graphics) - objective-c

Question

I am working on a game and I would like to add a proper slicing feature in it.. so when a sprite sliced, 2 new sprites should be created.. please check here
At the moment, I am just reducing the size and duplicating the sprites.. Something like this.. Thanks in advance..
- (BOOL) sliceSprite: (Sprite *) sprite withPath: (UIBezierPath *) slicePath
{
CGSize size = sprite.size;
size.width /= 2;
size.height /=2;
sprite.size = size;
sprite.sliced = YES;
Sprite *newSprite = [[Sprite alloc] initWithImage: sprite.image];
newSprite.position = sprite.position;
newSprite.size = size;
newSprite.sliced = YES;
newSprite.inView = YES;
newSprite.xVelocity = SLICE_SPEEDUP * sprite.yVelocity;
newSprite.yVelocity = SLICE_SPEEDUP * sprite.xVelocity;
newSprite.angularVelocity = -SLICE_REVUP * sprite.angularVelocity;
[sprites addObject: newSprite];
[newSprite release];
sprite.angularVelocity = SLICE_REVUP * sprite.angularVelocity;
sprite.xVelocity = -SLICE_SPEEDUP * sprite.xVelocity;
sprite.yVelocity = -SLICE_SPEEDUP * sprite.yVelocity;
return YES;
}
- (void) sliceSpritesInSwipePath
{
CGRect swipeRect = [swipePath bounds];
for (NSUInteger i = 0; i < [sprites count]; i++)
{
Sprite *sprite = [sprites objectAtIndex: i];
if ([sprite intersectsWithPathInArray: swipePoints
inRect: swipeRect])
if ([self sliceSprite: sprite withPath: swipePath])
{
[self resetSwipe];
if (![sliceSound isPlaying])
[sliceSound play];
break;
}
}
}

Answer 1

Is the specific line of splitting required? Fruit Ninja just spawns two halves of the fruit, as if it was split down the middle, this would be quite easy to do:
Create two sprites which are half the width of the original sprite
Position them 1/4 and 3/4 of the way along the original sprite's horizontal centre line
Add rotation/acceleration etc.
Modify texture coordinates so that the left sprite has the left half of the texture and the right sprite has the right half of the texture.

Answer 2

Since you're using CoreGraphics here, why not simply use a clipping path when drawing the sprite(s)?
Duplicate the sprite to be sliced, then apply simple polygons masking the two halves as their respective clipping paths. The function you need is called CGContextClip and a short tutorial can be found here.
Edit: The tutorial lists this example:
CGContextBeginPath (context);
CGContextAddArc (context, w/2, h/2, ((w>h) ? h : w)/2, 0, 2*PI, 0);
CGContextClosePath (context);
CGContextClip (context);
This sets the current path to a circle, then applies the current path as the clipping region.