How to check if sprites are hit in special order - cocos2d-iphone

Question

I have 3 0f 8 sprites on screen that I would like the reader to hit in order:
touching the egges first, then the sugar and finally the lemon (if done correctly a gold cup appears)
EggsSprite
SugarSprite
LemonSprite
the functions I have work but i would like to know if there an easier way to maintain and extend to other sprites onscreen (I have 8 sprites and hope to produce different "recipies")
ccTouchesBegan I detect touches on the sprites
if(CGRectContainsPoint(EggsSprite.boundingBox, location))
{
EggsSprite_is_hit = YES;
NSLog(#"EggsSprite_is_hit = YES");
}
if(CGRectContainsPoint(SugarSprite.boundingBox, location))
{
SugarSprite_is_hit = YES;
NSLog(#"RunCheckSugar");
[self CheckSugar];
}
if(CGRectContainsPoint(LemonSprite.boundingBox, location))
{
NSLog(#"RunCheckLemon");
LemonSprite_is_hit = YES;
[self CheckLemon];
}
this runs
-(void)CheckLemon
{
NSLog(#"LemonSprite is hit");
if(MeringueUnlocked == YES)
{
NSLog(#"You made a merangue");
Award.opacity=255;
}
else if(MeringueUnlocked == NO)
{
NSLog(#"Incorrect order");
EggsSprite_is_hit = NO;
LemonSprite_is_hit = NO;
SugarSprite_is_hit = NO;
MeringueUnlocked = NO;
}
}
-(void)CheckSugar
{
if(SugarSprite_is_hit == YES && EggsSprite_is_hit== YES)
{
NSLog(#"SugarSprite is hit");
NSLog(#"And Egg Sprite is hit");
SugarSprite_is_hit = NO;
MeringueUnlocked = YES;
}
else if(SugarSprite_is_hit == YES && EggsSprite_is_hit== YES)
{
NSLog(#"SugarSprite not hit ressetting all");
EggsSprite_is_hit = NO;
LemonSprite_is_hit = NO;
SugarSprite_is_hit = NO;
MeringueUnlocked = NO;
}
}
It seems to work ok, but it would be horrible to extend, I cant seem to find any examples on touching sprites in order so any psudo code ideas will be welcome :) as its the approach that Im more stuck on since I'm new to coding.
with thanks :)
N

Answer 1

When your sprites are created, assign to their 'tag' properties order in which they should be hit:
EggsSprite.tag = 1;
SugarSprite.tag = 2;
LemonSprite.tag = 3;
Then make an instance variable to store index of last sprite hit:
int _lastSpriteHitIndex;
and for index of last sprite in your sequence:
int _finalSpriteIndex;
Set its value somewhere in init (or whatever method you use to create your layer):
_finalSpriteIndex = 3;
Then in your touch handler:
// find sprite which was touched
// compare its tag with tag of last touched sprite
if (_lastSpriteHitIndex == touchedSprite.tag - 1)
{
// if it is next sprite in our planned order of sprites,
// store its tag as _lastSpriteHitIndex
_lastSpriteHitIndex = touchedSprite.tag;
}
else
{
// if it's wrong sprite, reset sequence
_lastSpriteHitIndex = 0;
}
if (_lastSpriteHitIndex == _finalSpriteIndex)
{
// Congrats! You hit sprites in correct order!
}
Basically it's a finite-state machine in which hitting sprites in correct order advances machine to next state, and hitting wrong sprite resets machine to initial state. _lastSpriteHitIndex repesents current state, _finalSpriteIndex represents final state.
If you don't want to reset to initial state on wrong sprite hit, just remove else clause - without it machine will simply not advance when hitting wrong sprite.