[osg-users] DDS with DXT1 with and without alpha

Hi All, I have been investigating issues with handling of .dds image files that contain DXT1 compressed RGB data, with some of these files being picked out as being RGBA because they have a black pixel within them. I've looked at what documentation on DXT1 I can find on the web and have what

Re: [osg-users] DDS with DXT1 with and without alpha

Hi All, I have now implemented the various options I suggested in my previous post, and for now have opted to default to DXT1 RGB pixle format for DXT1 files, unless the alpha bit in the dds header is set, then it will choose DXT1 RGBA pixel format. The OSG's DDS plugin does set the alpha bit

Re: [osg-users] DDS with DXT1 with and without alpha

Lewandowski -Oryginalna wiadomość- From: Robert Osfield Sent: Thursday, April 14, 2011 1:03 PM To: OpenSceneGraph Users Subject: Re: [osg-users] DDS with DXT1 with and without alpha Hi All, I have now implemented the various options I suggested in my previous post, and for now have opted

Re: [osg-users] DDS with DXT1 with and without alpha

Hi Wojtek, On Thu, Apr 14, 2011 at 12:23 PM, Wojciech Lewandowski lewandow...@ai.com.pl wrote: I hope I do not spread misinformation, as I am not fully sure nor I know exact details but I believe that logic for finding if DXT1 pixels are transparent, should first check the order of entries in

Re: [osg-users] DDS with DXT1 with and without alpha

14.04.2011 16:16, Robert Osfield wrote: The heart of the problem is that the DDS file format doesn't distiguish between the two varients of DXT1, there is an alpha bit in the DDS header that could be used, but 3rd party tools like nvdxt and nvcompress that write DDS files don't set this bit so

Re: [osg-users] DDS with DXT1 with and without alpha

14.04.2011 16:34, Mikhail I. Izmestev wrote: 14.04.2011 16:16, Robert Osfield wrote: The heart of the problem is that the DDS file format doesn't distiguish between the two varients of DXT1, there is an alpha bit in the DDS header that could be used, but 3rd party tools like nvdxt and

Re: [osg-users] DDS with DXT1 with and without alpha

14.04.2011 16:43, Mikhail I. Izmestev пишет: 14.04.2011 16:34, Mikhail I. Izmestev wrote: 14.04.2011 16:16, Robert Osfield wrote: The heart of the problem is that the DDS file format doesn't distiguish between the two varients of DXT1, there is an alpha bit in the DDS header that could be

Re: [osg-users] DDS with DXT1 with and without alpha

Hi Mikhail, I think you have mis-intrepted my suggestion that DTX1a and DTX1c have essential the same header and contents - I mean in that they are the same format in memory so we can't distinguish between the two. One would not expect nvcompress to produce the same output for DXT1a and DTX1c