Implementing powerUps to change entire game state in cocos2d? - iphone

Question

I asked a question recently that sort of involved implementing power-ups; however, I have decided that I want to go about it a different way.
In my game, I have an endless scrolling background and the main character moving to the right while collecting coins.
When the player hits the blue coin, the power-up, I want 1. the character to change to a blue color (I have the frames for this), 2. the background to go blue, and 3. the platform to change blue (have images for this); I would like all these factors to take place for a 20 second period of time.
I planned to do this by having a Blue class with a blue instance variable (public variable) that I would set to YES and NO accordingly (if a blue coin has been hit) in my other classes (Platform class, Player class). However, it is not efficient and does not work for when I incorporate a timer.
Does anyone have an idea on how to implement the power-up?
This is my code for when the blue coin is hit by the player:
// try remove blue coin
- (void) tryRemoveBluecoin
{
NSMutableArray * currentBluecoinArray = [self getcurrentBluecoinArr];
if(currentBluecoinArray)
{
int playerY = ((CCLayer*)(self.player)).position.y;
for(int x=0; x<[currentBluecoinArray count];x++)
{
CCSprite *bluecoin = [currentBluecoinArray objectAtIndex:x];
if(abs(bluecoin.position.x+bluecoin.parent.position.x-[Player initX])<50)
{
if(abs(bluecoin.position.y+bluecoin.parent.position.y-playerY)<30 && bluecoin.visible && bluecoin.visible)
{
[bluecoin.parent removeChild:bluecoin cleanup:YES];
CGSize winSize = [[CCDirector sharedDirector] winSize];
[[SimpleAudioEngine sharedEngine] playEffect:#"jump.wav" pitch:1 pan:0 gain:1];
// SET BLUE VARIABLE TO YES
NSLog(#"BEGIN BLUE POWER UP EFFECTS FOR 20 SECONDS");
}
}
}
}
[self hitTestOB];
}
Thanks for any ideas you have!

Answer 1

Now, it has been some time since I last used Cocos2d, but you are aware that you can actually set color-information to nodes, right? This sounds like a much more sensible way to go down. Design your sprites with this in mind and keep an array with all elements you need to color.
Have a method defining the new color based on your game state, the game state enums can be matched with an NSInteger property on your power-ups for instance.
ccColor3B color;
// _state being an NSInteger ivar
// the different states defined in an enum
switch (_state) {
case gameStateBlue:
color = ccc3(0, 0, 255);
break;
case gameStateGreen:
color = ccc3(0, 255, 0);
break;
default:
break;
// etc.
}
send this color information to a method which handles your array of sprites like this:
for (CCSprite *sprite in _arrayOfSpritesToChangeColor) {
sprite.color = color;
}
This will demand planning ahead with your assets, but a lot more flexibility down the line if you want to experiment with different colors and effects. It is a lot less taxing as well as you won't need to swap a bunch of assets to achieve what you want. Now, my Cocos is rather rusty so I might have messed some details up, but the general idea should be sound.
Edit: An alternative to holding reference to the sprites in an array is to have your own sprite subclass and let that subclass have a CCSprite colorSprite property. Then you could loop through the children of your scene and change the sprites that have this property.