cocos2d for iPhone » Topic: PNG Alpha Transparency showing dark border around sprite

johannth on "PNG Alpha Transparency showing dark border around sprite"

johannth — Mon, 31 Aug 2009 14:00:22 +0000

I was wondering if there was any way to solve this dark-edge in simulator problem when using cocos 0.8? I tried messing with ccMacros and set GL_BLEND_SRC to GL_SRC_ALPHA but it had no effect. Are these default settings overridden somewhere in the code?

CJ on "PNG Alpha Transparency showing dark border around sprite"

CJ — Thu, 13 Aug 2009 06:42:57 +0000

libpng solves all problems from my pov. So I changed my TextureMgr to default to use libpng for handling .png files. One caveat is I also had to add new texture format support to Texture2D if you want to use png's w/o alpha channels (RGB888) or grayscale pngs. I'll be posting a patch shortly to the google issues list.

zombie on "PNG Alpha Transparency showing dark border around sprite"

zombie — Wed, 12 Aug 2009 21:54:17 +0000

I use libpng for the simulator and the normal method for the device. When making screenshots it is better when everything looks right :) I made the mistake to release some with blending problems. Our graphics artist was not happy about that :)

- zombie

riq on "PNG Alpha Transparency showing dark border around sprite"

riq — Wed, 12 Aug 2009 12:47:02 +0000

and look at this post too:
http://www.cocos2d-iphone.org/forum/topic/1041

crmagicxxx on "PNG Alpha Transparency showing dark border around sprite"

crmagicxxx — Wed, 12 Aug 2009 12:39:40 +0000

Try using cocos2d 0.8 and device instead of simulator. Before 0.8 I had same problems, solving was boring, but with 0.8 everything works ok on device. In simulator it still has problems, but who cares, simulator is just for preview... There are ways to set it right even in simulator but why bothering?

If you still want to solve it old way, look this 2 posts:
http://www.cocos2d-iphone.org/forum/topic/587
http://www.cocos2d-iphone.org/forum/topic/713

noshbar on "PNG Alpha Transparency showing dark border around sprite"

noshbar — Wed, 12 Aug 2009 12:03:48 +0000

Howdy, I don't know anything about this, but I'm suffering from the same problem, and am going to take my first look at it tonight.

Having found this:
http://www.cocos2d-iphone.org/wiki/doku.php/faq#my_png_doesn_t_look_like_in_photoshop
... perhaps the blend function needs to be changed?

CJ on "PNG Alpha Transparency showing dark border around sprite"

CJ — Wed, 12 Aug 2009 07:34:25 +0000

I searched google already but the previous thread I found didn't really explain what was happening very well, so I'm going to ask...

Why is it when I have a sprite using a PNG 24-bit from photoshop that it renders with a dark edge in my game. I have the director set using [[Director sharedDirector] setPixelFormat:kRGBA8]; before I attach it to the window

And I tried this before/after the actual creation of my sprite:
[Texture2D setDefaultAlphaPixelFormat:kTexture2DPixelFormat_RGBA8888];
...
[Texture2D setDefaultAlphaPixelFormat:kTexture2DPixelFormat_Default];

But no luck.

Please help :)