cocos2d for iPhone

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

1. 

   patrickC
   Member

   Hi there,
   I was hoping somebody could help me figure this out.
   I need to have a very big TileMapAtlas in my game, as it is the performance suffers terribly so, as I see it, I have two solutions:
   a) Modify the TileMapAtlas, so that it only draws the quads that are visible on screen, so at every gamestep calculate which tiles are to be displayed
   b) Divide the big map into lots of little maps, performance doesn't seem too good, also since the texture file is the same will they be sharing it, or is it being reallocated every time?

   I'd be more prone to go for solution "a" but not sure how and if it's possible, any help on the matter is greatly appreciated!
   Thanks!
   Patrick

   Posted 2 years ago #
2. 

   riq
   Key Master

   a) how many tiles are you going to draw ?
   b) how big are the tiles ?

   regarding a) and b), did you try using 4-bit (pvrtc) or 16-bit textures ?

   Posted 2 years ago #
3. 

   patrickC
   Member

   Thanks for the reply riq.
   a) the tilemap is quite big (say up to 512x512), but if I only want to draw what I see onscreen that would be around 80-100 tiles I'd say.
   b) the tiles are 64x64. Originally they were 32x32 and I was scaling it up by 2 (I'm going for a pixely look), but that creates lines in between the tiles when the camera is moving (ie: always)
   I've tried using pvtr but, since the tiles are all packed closely together (and TileMapAtlas doesn't seem to support spacing and margins in the texture file), I get very nasty artifacts on the edges between the tiles, and lots of them mix in with the rest at the edges (i read that it's a common downfall of pvtr compression).
   At the moment I'm using 8bit pngs.
   I implemented the "b" method just yesterday but performance doesn't seem too good, I'll try making the divisions of the tilemap even smaller but I still think option A would be best, no?
   Thanks for your time and help!
   Patrick

   Posted 2 years ago #
4. 

   riq
   Key Master

   If you are going to implement option a) you will need to rewrite TextureAtlas.

   And in every frame you will need to check if you current vertex array has all the needed tiles to draw.
   And you will need to add/remove tiles according to your position.

   Setting the tiles as not visible is not an option in your case.
   You will need to REMOVE from the vertex array the tiles that are not visible.

   Probably you will need to store all your tiles in a optimized data structure.

   But since you are going to have more than 260.000 tiles option a) and b) are more or less the same.

   Posted 2 years ago #
5. 

   jacob_f84
   Member

   we just did this for a game we're making right now. We added a draw function to TileMapAtlas and basically did all of the quad/indices management in TileMap. We are able to load arbitrarily long (currently 512x128 tiles with 16x16 tiles) maps and navigate around them at 60 FPS. The key is to re-write TileMapAtlas, not texture atlas, and load only the quads you need into an OpenGL buffer and then calculate the indices based on the loaded quads.

   Good luck!

   -Jacob

   Posted 2 years ago #
6. 

   Blue Ether
   Member

   jacob: According to copyleft, it would really be appropriate to make your modifications to TileMapAtlas available to the public.

   I for one would be interested.

   Posted 2 years ago #
7. 

   jacob_f84
   Member

   The problem right now is that our modifications are really app specific. In some cases I even have magic numbers that depend on the tile size. Actually, since that post I have done further optimizations to bring down the memory footprint as I describe here: http://f84games.com/developersNotebook.php

   Once this game ships we will take a look at how to implement our mods in a generic enough way to make it a useful part of the engine. Hopefully we'll be able to make a contribution within the next month or so.

   Posted 2 years ago #
8. 

   snoe
   Member

   This was going to be a big issue for me, so I posted my solution here, feel free to use it / post improvements:
   http://code.google.com/p/cocos2d-iphone/issues/detail?id=544

   Posted 2 years ago #

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