[osg-users] Need help with OSG Image.
Akhtar Shamim
I am facing a problem with OSG Image and would like to seek some advice from the community.
I have a model exported in IVE format. This model is just a quad with a texture mapped onto it. I want to retrieve the original image from osg::Image object and convert it to JPG/PNG or any other format. Seems simple, but I am not sure what is causing the problem.
The image when loaded using osgviewer looks perfectly fine. But when I debug and look at the contents of the osg::Image object I find that both the InternalTextureFormat and the PixelFormat are invalid.
_internalTextureFormat 33776 int
_pixelFormat 33776 unsigned int
The pixel size is 4 bits per pixel. I tried using osg::writeImageFile with extension as JPG, TGA and PNG. Nothing works. With extension as RGB the image is saved but is incorrect. I think it is because of the fact that the image is 4 bits per pixel.
So, what I did is to use ImageMagick to convert the image data buffer to a common format (JPG, PNG or TGA). However I am unable to do the conversion from the 4 bit per pixel to a 24 bit per pixel. Any help here would be greatly appreciated.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
unsigned int total_size_in_bytes = image->getTotalSizeInBytes();
unsigned int row_size_in_bytes = image->getRowSizeInBytes();
unsigned int image_size_in_bytes = image->getImageSizeInBytes();
unsigned char* ptr = image->data();
unsigned int size = w*h;
unsigned char* writePtr = new unsigned char[size];
memset(writePtr, 0, size);
// i convert to byte array (not sure if this is the correct way to do)
for(unsigned int i = 0; i < size; i+=2)
{
writePtr[i] = (ptr[i/2] >> 4);
writePtr[i+1] = (ptr[i/2] & 0x0F);
}
// now i have the byte array and i set to imagemagick
for (unsigned int y = 0; y < h; y++)
{
for (unsigned int x = 0; x < w; x++)
{
unsigned char c = writePtr[x+y*w];
Magick::PixelPacket* curMagickPix = 0;
curMagickPix = magickPixels + (y*w + x);
curMagickPix->red = c;
curMagickPix->green = c;
curMagickPix->blue = c;
}
}
delete [] writePtr;
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Regards,
Shamim
Ulrich Hertlein
On 30/06/10 20:51 , Akhtar Shamim wrote:
> I have a model exported in IVE format. This model is just a quad with a texture mapped
> onto it. I want to retrieve the original image from osg::Image object and convert it to
> JPG/PNG or any other format. Seems simple, but I am not sure what is causing the problem.
>
> The image when loaded using osgviewer looks perfectly fine. But when I debug and look at
> the contents of the osg::Image object I find that both the InternalTextureFormat and the
> PixelFormat are invalid.
>
> _internalTextureFormat 33776 int
> _pixelFormat 33776 unsigned int
They are not invalid, decimal 33776 is hex 0x83f0 is GL_COMPRESSED_RGB_S3TC_DXT1_EXT.
In the process of converting to .ive they have been compressed to speed up texture upload.
As far as I know no image exporter supports writing these compressed images.
You could render the texture to a framebuffer and read that back... :-/
/ulrich
_______________________________________________
osg-users mailing list
osg-...@lists.openscenegraph.org
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Farshid Lashkari
They are not invalid, decimal 33776 is hex 0x83f0 is GL_COMPRESSED_RGB_S3TC_DXT1_EXT.
In the process of converting to .ive they have been compressed to speed up texture upload.
As far as I know no image exporter supports writing these compressed images.
Ulrich Hertlein
Good point, but it will only save it in its compressed form, so one still needs to find a
tool to uncompress the file.
Cheers,
Farshid Lashkari
Good point, but it will only save it in its compressed form, so one still needs to find a
tool to uncompress the file.
Jean-Sébastien Guay
> If your are on Windows, the excellent (and free) Paint.NET image editor
> can open/save compressed dds files.
I personally like XnView (also free ($) but not free (libre) unfortunately).
Ulrich, it's really not hard these days to find something to open dds
files with. The DirectX SDK includes a viewer of course, GIMP opens and
saves them, osgviewer --image loads them, etc. Unfortunately OSG won't
convert internal image formats between load and save, so you can't just
load a dds and save a jpg/png/tga/bmp for example, but many tools can do
it (GIMP, command line ImageMagick, etc.)
Hope this helps,
J-S
--
______________________________________________________
Jean-Sebastien Guay jean-seba...@cm-labs.com
http://www.cm-labs.com/
http://whitestar02.webhop.org/