Fix bug: PremultipliedAlpha is not working for png #19112
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chongchaoyu
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chongchaoyu
changed the title
| @@ -1149,6 +1149,11 @@ bool Image::initWithPngData(const unsigned char * data, ssize_t dataLen) | |||
| { | |||
| premultipliedAlpha(); | |||
| } | |||
| else | |||
| { | |||
| _hasPremultipliedAlpha = true; | |||
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Why enable premultipliedAlpha even png format isn't RGBA8888, any errors? maybe you use CCImage in wrong way.
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@drelaptop
oh, yes, if png format is not RGBA8888, premultipliedAlpha should not be true.
But, there is a case, I want to use PMA pngs to improve performance and prevent blend artifacts, so I use Image::setPNGPremultipliedAlphaEnabled(false), but it doesn't work, because CCImage.hasPremultipliedAlpha() will return false at Texture2D::initWithImage if you don't set premultipliedAlpha to true when png format is RGBA8888.
I will resubmit a PR, the code is like the followings:
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@drelaptop The new PR is #19138, you can check it.
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sorry, you hope CCImage.hasPremultipliedAlpha() return true, but you did setPNGPremultipliedAlphaEnabled(false) before. that is confusing.
no need to new a PR for same bug fix, you can commit to same branch, then PR will auto update.
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@drelaptop setPNGPremultipliedAlphaEnabled(false) changes PNG_PREMULTIPLIED_ALPHA_ENABLED to false, it tells cocos2dx that pngs have been PMAed by developers, so cocos2dx needn't to do premultipliedAlpha, premultipliedAlpha takes about 40ms for 2048*2048 pngs.
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@drelaptop I read CCImage.cpp, and setPNGPremultipliedAlphaEnabled(false) maybe the only way to use PMAed pngs.
Doesn't cocos2dx support PMAed pngs?
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New PR is #19138. |
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