Re: Rendering grayscale on opengl using nsbitmaprep

[Fred Kiefer]

Now having had a short look at your code I am almost sure that my
initial suspicion is correct. You first convert a grey scale image into
an RGB one, that step should work. Next you copy the data of this
converted bitmap into a large data structure where you extended width
and height to the next power of two. Here you have to copy over each row
separately. (You could save that step by supplying a corresponding
bytesPerRow value into the conversion.) Then you call your
initWithData:... method and hand over an unpackRowLength you computed
from the original data. But you don't use that value instead you use the
rounded up width (Line 524).

Not that I understand any of the stuff that goes on in this method, but
I am very sure that this is the cause of your trouble.

Cheers
Fred


Am 25.02.2011 19:15, schrieb AN Indie:
> On Wed, 23 Feb 2011 15:22:09 +0530, Fred Kiefer <fredkiefer@gmx.de> wrote:
> 
> Sure. I always worried that, it may off the topic here.
> Code is already hosted on internet. It is hosted in a public git
> repository at github(https://github.com/ANindie/cocos2d-GNUstep).
> 
> You can take a quick look on problematic code at
> https://github.com/ANindie/cocos2d-GNUstep/blob/85c5097047126107ef225b9025e972b97e60335d/src/cocostep/CCTexture2D.m.
> 
> 
> I included th code you pointed here. Also added test case at
> https://github.com/ANindie/cocos2d-GNUstep/blob/85c5097047126107ef225b9025e972b97e60335d/src/tests/BasicSpriteTest/BasicSprite.m
> 
> 
> -Thanks
> Indie AN
> 
> 
> 
> 
>> Thank you, with that explanation I finally understand where you trying
>> to get to. And the code that I pointed you to should work quite well for
>> that purpose. My feeling is still that your code that is calling this
>> has a problem. If you want you can send me the code off line and I have
>> a quick look at what may go wrong here.
>>
>> Fred
>>
>> Am 23.02.2011 05:21, schrieb Indie AN:
>>> Ok. Let me clear it for once. I am trying to render image using
>>> opengl, that we normally do for games. Opengl do not speak nsimage.
>>> They speak textures . All i needed is magic piece of code that
>>> converts every image to raw rbga or rbg data. In mac they do using
>>> coreimage framework.         But its ok. I can live happily without
>>> gray scale images. White image is sufficient.  Thanks to everybodies
>>> time.
>>>
>>> On 2/16/11, Fred Kiefer <fredkiefer@gmx.de> wrote:
>>>> Sorry, I still don't understand your problem. Why are you converting
>>>> the
>>>> image? The standard code should work fine in displaying it. Actually
>>>> the
>>>> code I pointed you to is used for that.
>>>> From your screen shot I would expect that your drawing code uses the
>>>> wrong sizes. To verify this it would help if you sent a bit more of
>>>> your
>>>> code.
>>>>
>>>> Fred
>>>>
>>>> PS: For drawing pre-multiplied images get used. Better convert in to
>>>> that format. But this is completely unrelated to your problem.