Re: Rendering grayscale on opengl using nsbitmaprep

[AN Indie]

Hi,
 I accept their is mismatch between parameter/arguments. But this code  
just works!
[
 But good news is, I was able to reproduce the bug in package  
gnustep-examples-1.2.0

I modified NSImage test case a little and  reproduced this bug!!


I changed


image = [[NSImage alloc] initWithContentsOfFile: file ];
[mview setImage: image];

with


image = [[NSImage alloc] initWithContentsOfFile: file ];
NSImage  * aximage =  [[NSImage alloc] initWithData:[image  
TIFFRepresentationUsingCompression:NSTIFFCompressionNone factor:0]];
[mview setImage: aximage];

An now  the gray scale image is not renders properly.


I attached test case along with this mail. Please confirm with latest  
GNUstep as I am using the older version.

-Thanks
AN Indie

On Sat, 26 Feb 2011 01:21:36 +0530, Fred Kiefer <fredkiefer@gmx.de> wrote:
> 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.


--
iPhone development on Linux! https://github.com/ANindie/cocos2d-GNUstep

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