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Main forum => GLBasic - en => Topic started by: fjsantosb on 2010-Mar-26

Title: Gradients on iPhone problem?
Post by: fjsantosb on 2010-Mar-26
Hi there,

I have some problems when using gradients on iPhone. On emulator all looks great, but when i build to iPhone i get somewhat gradient effect like using low bit depth.
If i move the image to iPhone directly, i can see the gradient effect perfectly clear.
I dunno if it normal (if iPhone get low bit depth when gaming), or if it is anything related to GLBasic.

Anyone has experimented some similar?

King Regards, fjsantos.
Title: Re: Gradients on iPhone problem?
Post by: Ozden79 on 2010-Mar-26
Hello Francisco,

Yes, I saw the same thing, in our game "FastBall". It seems IPhone has 16 bit depth and the images you create in 32 bit appears to have less colors on IPhone thus a more noticable color changes, especially with gradient effects.

Özden
Title: Re: Gradients on iPhone problem?
Post by: fjsantosb on 2010-Mar-27
Hi Ozden,

Yep, it's seems to be something related to bits depth; but is extrange that if you sync the same image on iPhone, the gradient seems to work well. (So it's seems to be only related to games).

Anyway, thanks for repply! ^_^

King Regards, fjsantos.
Title: Re: Gradients on iPhone problem?
Post by: Ian Price on 2010-Mar-27
The reason is indeed due to bit-colour depth. The Wiz has the same problem.

According to Wiki, the iPhone is -
Quote
18-bit (262,144-color) LCD with 163 pixels per inch (ppi)

So anything over 16bit colour depth will look different and it's not GLBasic or only games. So don't bother wasting memory on anything above 24bit colour.
Title: Re: Gradients on iPhone problem?
Post by: fjsantosb on 2010-Mar-28
Hi Ian,

Thanks for your help, but the problem here, is that when I sync the image with my iPhone, its look kinda different that when i code as 'game background'. That why i am a bit confusing :S. Maybe they use different algorythm to compress?

King Regards, fjsantos.
Title: Re: Gradients on iPhone problem?
Post by: mentalthink on 2010-Mar-28
Hi Fj, try to make the gradient whit another soft, in my case the gradients make in photoshop don´t works well, but makes in 3ds max in .png 16bits works well for me.

The photoshop make in some cases things wrong, another example is the efects, if you make a glow whit PS, don´t have transparency on Iphone, but make on max or another soft 3d, the glow works well, the output format it the same, but I thin kevery aplicatión have his own behaviors about the outputs formats.

Best Regards,
Iván J.
Title: Re: Gradients on iPhone problem?
Post by: Moru on 2010-Mar-28
If you want transparency with PhotoShop you need to "Save for web..." and choose one of the PNG presets and make sure the checkbox "Transparency" is set.
Title: Re: Gradients on iPhone problem?
Post by: mentalthink on 2010-Mar-28
Ok, Moru thanks for the reply.

I don´t probe this what you comment.

Best regards

Iván J
Title: Re: Gradients on iPhone problem?
Post by: fjsantosb on 2010-Mar-29
Hi,

Thanks for your reply.

I think the problem is anything related to bit depth finally.

King Regards, fjsantos.