cocos2d for iPhone

A fast, easy to use, free, and community supported 2D game engine

1. 

   AggroPanda
   Member

   Hi All,

   I've been playing around with cocos2d for a while now and I've decided I'm going to use it to make a small game to test the engine before going on to bigger and better games.

   Therefore, I've decided I'd like to make a sort of Doodle game clone (remember this is only for testing, to get my head around cocos2d, I don't expect to make millions :p) so I'd just like a bit of advice on the best practices on making such a game.

   The game will basically be as simple as this:

   - A Panda will move from left to right on the screen and must avoid being captured by zoo keepers. He must eat food to keep going.
   - You score higher by getting as far as possible.
   - If you get captured or run out of engine you fail.
   - The game must run for as long as the player can keep going for.

   I already know how to add sprites to a scene and get them moving around, including animation etc, however my question is this:

   - Is it better to move the Panda or the zoo keepers and food? Also could you please explain how I'd go about moving the other sprites, i.e. if it's best to move the Panda, how should I update the other sprites?

   I hope I've provided enough information here, if not please say so and I'll try and provide you with more :)

   Thanks in advance,

   AggroPanda

   P.S. If there is already a tutorial for this sort of thing, please link me to it and I'll take a look, cheers.

   Posted 1 year ago #
2. 

   gaminghorror
   Member

   You would want to move the scenery and keep your player character (Panda in this case) fixed. Makes things a whole lot easier i think since the coordinate space is always screen coordinates. What i mean by this is that as the game is moving forward, the things coming in from the right are just added to the game at the right moment just before it enters the screen, and at the left side when things leave the screen you just discard them. That makes it easy to randomize what appears and also you're able to re-use everything. Eg you can have a pool of 4 Zookeepers that can be on the screen at once and re-use them simply by placing them back at the right side of the screen. That way you avoid a lot of alloc/dealloc cycles and maintain a steady framerate. It also simplifies collision checks as you can disregard any sprite that is not within the player's area within which it can move - if it can move along the x-axis at all.

   So how do you move stuff from right to left? It's rather easy actually, everything has an update method that subtracts X from the sprite's x position every frame. X determines the scroll speed. Why not use Move Actions? Because they cause a lot of alloc/dealloc and they can't make things easier than simply subtracting X from the x position each frame. X can also vary, for example if you need slow and fast moving elements or want parallax effects. But that's really all there is to it. Next step is to create sprites just outside the right side of the screen and remove them just outside the left side of the screen. Again: best to reuse a pool of sprites.

   Posted 1 year ago #
3. 

   abitofcode
   Moderator

   I'd do exactly what @gaminghorror has suggested.

   Don't optimize too early but bear in mind that moving large RGBA8888 textures will not be as efficient as smaller RGBA4444 ones for example. I found having a static background with 128x128 tiles scrolled over it (for mountains) worked well. If you use a 320 high texture for example it'll actually round up to 512 in memory (powers of 2).

   I have only 2 AtlasSpriteManagers in STAPig with the particle effects sandwiched in between, I don't know if having more would have had an effect.

   Posted 1 year ago #
4. 

   AggroPanda
   Member

   Thanks guys, just what I needed :)

   I've downloaded the tweejump source code so I can have a look at that too.

   I've also been trying to set up a good base to start from, how does this look?

   Main : CCLayer
   - (void) step:(ccTime)dt

   Item : CCSprite
   - (void) PlaySound:(NSString *)sound

   Keeper : Item
   - (CGRect) GetRect // Returns the rect for the keeper on the sprite sheet
   - (void) Update // Updates the keeper's position
   - (BOOL) CollidedWithPanda
   + (id) init: (CCSpriteSheet *)spriteSheet

   Panda : Item
   - (CGRect) GetRect // Returns the rect for the panda on the sprite sheet
   - (void) Update // Updates panda's position
   + (id) init: (CCSpriteSheet *)spriteSheet

   Coin : Item
   - (CGRect) GetRect // Returns the rect for the coin on the sprite sheet
   - (void) Update // Updates coin's position
   - (BOOL) CollidedWithPanda
   + (id) init: (CCSpriteSheet *)spriteSheet

   I can do this on the main.m to add a new keeper:

   
CCSpriteSheet *spriteSheet = (CCSpriteSheet *)[self getChildByTag:kSpriteManager];
Keeper *keeper = [Keeper init:spriteSheet];
[spriteSheet addChild:keeper z:3 tag:currentKeeperTag];


   And then to move the all the keepers I can do this in the step method of the main.m:

   
CCSpriteSheet *spriteSheet = (CCSpriteSheet *)[self getChildByTag:kSpriteManager];

   for (int tag = kCloudsStartTag; tag < kCloudsStartTag + kNumClouds; tag++)
{
Keeper *keeper = (Keeper *)[spriteSheet getChildByTag:tag];
[keeper update];
}


   Does this look like a good way to do things?

   Cheers in advance,

   AggroPanda

   Posted 1 year ago #
5. 

   AggroPanda
   Member

   also abitofcode, how did you do you the thruster button on STAPig? is it just a sprite with touch enabled?

   Cheers,

   AggroPanda

   Posted 1 year ago #
6. 

   Techy
   Member

   I bet he used a menu item... CCMenuItemImage or CCMenuItemSprite then added it to a CCMenu and displayed it

   Posted 1 year ago #
7. 

   abitofcode
   Moderator

   @AggroPanda - The menus and game originally all melded into one another, so I had some custom button code driven by the current state. Since adding the cut scene images though the whole point of the custom code is effectively negated and I could have just gone with a lot of the off the shelf cocos2d stuff. I'll probably do a rebuild when I do the first major update, just need to find some time to fit it in at the moment.

   Posted 1 year ago #

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