A fast, easy to use, free, and community supported 2D game engine
Hi!
I recently released Rope'n'Fly to the appstore which is using cocos2d. (Rope'n'Fly is/was #2 top paid app in US, UK and Japan).
I used cocos2d 0.7.0 and Box2D to build Rope'n'Fly.
Is there any good reason to update to the newest cocos2d, e.g. performance improvements? Anyway, thanks for such an great and easy to use framework!
jonathan0382
Member
Hey Robert, congratulations on an excellent app. I've been playing the lite version for a week now and love it.
I'm not too knowledgeable on the upgrades, but I do have a question concerning the ropes in your game. Are they are series of boxes, or how are they formed?
I'm glad you liked it. Regarding the rope, its basically a rope built of objects with a circle shape and various different type of joints between the objects and the head. Overall gravity and object density gets changed on the fly to simulate the rope more accurately.
Codemattic
Moderator
I didnt know it was a cocos2d game - I love Rope'n'Fly and play quick games often - Congratulations, its a very clever and addictive game.
Normally I can tell cocos games by how the menu/buttons work - so I guess you created your own button event code.
Ever worry that Marvel's lawyers will give you a call? ;)
He doesn't have to worry about Marvel's lawyers (not sure if you were joking about that, but I thought about the same issue for a moment when I started playing it). For one, you can change your character's colors. Secondly, in a recent update he changed the app. icon to no longer show the character, which looked vaguely like [insert well known character here]. Thirdly, he could simply change the default colors at this point if he gets any serious flack (if they even match [well known character]). Congrats on this Robert -- it's the perfect example of an idea that is novel/simple/fun. The input machanic (tapping the buildings) is simple/completely appropriate. I bought the paid version almost immediately. I was pretty much sure it was cocos2d based on the look/feel of the layers, the menus, and the leaderboards. It's pretty cool that the gameplay of this feels similar/comparable to the core gameplay of a title that cost a lot more to make (Spiderman 2 (oops, I said the well-known character's name))...
Sorry for the off-topic question it's totally inapropriate, but - is there some sort of a demo for a platformer such as this one, in which you move the map and the character...
I mean, you interact with the surrondings and move the player and the map moves accordingly...
I hope you catch my drift... (is this how it's said?)
jonathan0382
Member
@Codemattic:
>> Normally I can tell cocos games by how the menu/buttons work - so I guess you created your own button event code.
The buttons are just sprites and labels with a few actions attached to it.
>> Ever worry that Marvel's lawyers will give you a call? ;)
Happend already. ;)
@natanavra:
>> Do you use chipmunk?
The very first version used chipmunk. (I was familiar with chipmunk already when I started Rope'n'Fly). But soon I switched to Box2D. For Rope'n'Fly Box2D has the better and more accurate physics.
Regarding my initial question. Would switching to cocos2d 0.8.0 from 0.7.0 give any performance increase? (Rope'n'Fly runs at the limit currently, looks like that drawing the transparent sprites for the buildings are very CPU/GPU intensive).
Thanks,
Robert
http://www.iphone-apps.at
http://www.skyos.org
Steve Oldmeadow
Administrator
@Robert - I don't think upgrading to 0.8 will give you a performance boost since it doesn't look like you use any/many actions.
How are you drawing those buildings? How do you draw the man and the rope? It looks like you might be drawing a lot of primitives, in which case if you aren't batching your drawing that could be hitting your performance.
Thanks for the reply. The only bottleneck I experience depends on the amount of buildings I draw. Drawing the guy or the rope doesn't have an influence on the performance at all.
The buildings itself are 32bit PNGs loaded as sprites. The size of these sprites makes a huge difference performance wise. (e.g. increasing the width of each building by just 10 pixels results in a performance drop of about 15 frames). Are there any possible optimizations for such textures? E.g. a more GPU friendly pixel alignment?
Steve Oldmeadow
Administrator
You should switch to using AtlasSprites for the buildings.
Steve Oldmeadow
Administrator
AtlasSprites that belong to an AtlasSpriteManager all share the same texture (sometimes called sprite sheet, sometimes called texture atlas). This means you can draw a lot of images with one OpenGL call and one texture binding which can equate to a huge performance increase. You have to pack your images into a single texture though, do not simply switch over to using AtlasSprites with one AtlasSpriteManager for every Sprite that you currently have or you won't see any benefit.
Sprites, on the other hand, require one OpenGL call and one texture binding for every Sprite that is drawn.
Codemattic
Moderator
An AtlasSpriteManager has one big texture holding the images for multiple AtlasSprites. That way opengles has to do less texture switching which is expensive. Sprite just has each image as its own texture, and so every time a sprite is drawn its a texture switch.
">> Ever worry that Marvel's lawyers will give you a call? ;)
Happend already. ;)"
D'oh - well at least you were able to make a few changes and keep them off your back and still keep your app in the store. Even though you could change it in the preferences the red/blue theme was a little too close.
Thanks, will definitely look at AtlasSprite, using them makes sense from your explanation.
Btw, I just updated the project to cocos2d-0.8.0, most things appear to work fine, but I got a little problem with sprites/textures.
If you look at the screenshot of Rope'n'Fly you will see buildings behind the top most layer are grayed out. Internally this are just the normal buliding sprites, but scaled, grayscaled and opacity set. To make the sprite grayscaledI just set the sprites color to a gray value, e.g r=g=b=15;.
Unfortunately this appears to not longer work with 0.8.0, the buildings have their opactity set, but they are drawn with their original color instead of grayscaled. Did I miss something here?
Thanks!
Steve Oldmeadow
Administrator
Setting r,g,b is deprecated - try using setColor instead.
tried this already, actually when I debug TextureNode.m I see that
glColor4ub( color_.r, color_.g, color_.b, opacity_);
uses the correct colors (15,15,15,100) in my case.
Maybe anything additional which must be set?
I see there is also a difference regarding glBlendFunc from 0.7.0 to 0.8.0. Maybe this causes the side effect.
Steve Oldmeadow
Administrator
It could be to do with setOpacityModifyRGB. Are you testing this on a device? I believe the simulator doesn't behave correctly with regard to premultiplied alpha on PNGs.
@robert:
yes, v0.8 renders the images correctly, which might not be want you want:
http://www.cocos2d-iphone.org/wiki/doku.php/faq#my_png_doesn_t_look_like_in_photoshop
this post might also help you:
http://www.cocos2d-iphone.org/forum/topic/824
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