[osg-users] Image::isImageTranslucent() failed when using DXT3 dds texture

amalric alexandre alex.pixxim at gmail.com
Tue Sep 16 03:45:25 PDT 2008


Hi Robert,

Thank you for your support ;-)

Is it possible to add the

GL_COMPRESSED_RGBA_S3TC_DXT3_EXT
format for the moment ?

I've found at
http://www.oldunreal.com/editing/s3tc/ARB_texture_compression.pdf

*

Table 2: S3TC compressed internal formats and their corresponding
uncompressed input format.
*

S3TC Compressed Internal Format               -> Base Internal Format

GL_COMPRESSED_RGB_S3TC_DXT1_EXT -> RGB

GL_COMPRESSED_RGBA_S3TC_DXT1_EXT -> RGBA

GL_COMPRESSED_RGBA_S3TC_DXT3_EXT -> RGBA

GL_COMPRESSED_RGBA_S3TC_DXT5_EXT -> RGBA
DXT3 seems to bee like RGBA, are you ok to add :


case(GL_COMPRESSED_RGBA_S3TC_DXT3_EXT):

offset = 3;

delta = 4;

break;
to Image::isImageTranslucent() ?

Kind regards

2008/9/16 Robert Osfield <robert.osfield at gmail.com>

> Hi Amalric,
>
> On Tue, Sep 16, 2008 at 11:04 AM, amalric alexandre
> <alex.pixxim at gmail.com> wrote:
> > Is it possible to handle pixel format corresponding to DXT3 format ?
>
> It's possible, but far more complicated than with uncompressed pixel
> formats as you'll need to unpack the pixels for each of the
> compression scheme.  It'd be great to have code to uncompressed blocks
> of pixels, but since the compression schemes haven't been widely
> published it does mean you'll need to go route out the specs.   You
> have my support and encouragement if you wish to explore this route.
>
> Robert.
> _______________________________________________
> osg-users mailing list
> osg-users at lists.openscenegraph.org
> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
>



-- 
Alexandre AMALRIC Ingénieur R&D
===================================
PIXXIM S.A. 73E, rue Perrin-Solliers 13006 Marseille
http://www.pixxim.fr
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