Hi Andreas,
DDS is flexible container format capable of storing 2D, 3D, Cube and Array
Textures (with or without mipmaps) in many pixel formats. Block compressed
pixel formats like DXTn, RGTC (3Dc) and LATC are supported. Of course I
don't know all existing image formats but I learned about a few and I guess
this is the only format capable to store every type of texture with every
type of pixel format used nowadays.
DDS files are not compressed for file storage and they don't require
decompression which means they load quite quicly. PNG and JPG require this.
DDS in OSG has support for a number of most used pixel formats (but not all)
and 2D & 3D textures. I am not 100% sure here but CubeMaps and Texture
Arrays are not supported yet by OSG DDS reader writer.
But there is one issue you should be aware about. DDS is simple wrap of
DirectDrawSurface texture. DirectDraw and Direct3D assume that surface
origin is in upper left corner while OpenGL assumes lower left. To maintain
orientation its neccessary to flip DDS files that were built for DD, D3D
use. This flip does require some software work after image was loaded. Or
alternatively one may flip the image in authoring tools before saving as
DDS.
But if you generate these DDSes with OSG and later load them with OSG
problem disappers because you use the same oritentation they were created
in.
Cheers,
Wojtek Lewandowski
----- Original Message -----
From: <[email protected]>
To: <[email protected]>
Sent: Friday, July 24, 2009 11:03 AM
Subject: [osg-users] question about available feature support for DirectDraw
Surface
Hello OpenSceneGrapher!
I want to texture by shading some geodes that are sticked together as a
huge landscape. I wonder what file format for the textures is most
suitable. Usually I take squared JPG. But short while ago I read about
Direct Draw Surface (DDS) which supports mipmaps.
Does anybody here has experience in using DDS? I'm interested in the OSG
support of the DDS features and if it's worth using this file format
instead of the classic one's like JPG or PNG.
Looking forward to your suggestions.
Regards,
--
Andreas Richter
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