Requesting colour dither discards alpha information

GoogleCodeExporter commented 8 years ago

What steps will reproduce the problem?
1. Convert from a TGA with an alpha channel to a DXT-compressed format
(DXT1a, DXT3, DXT5 have alpha)
2. CompressionOptions::setQuantization( true, false, false );

What is the expected output? What do you see instead?

Instead of seeing a similar image to the input image, the resulting image
is completely opaque, with alpha values of 255 right across the board.

What version of the product are you using? On what operating system?

Tested with NVidia Texture Tools 2.0.3 on Windows XP (32-bit).

Please provide any additional information below.

It seems this line is discarding any alpha information in the source image:

Color32 pixel16 = toColor32( toColor16(pixel32) );
Line 117 of nvimage/Quantize.cpp

Original issue reported on code.google.com by jon...@gmail.com on 11 Jun 2008 at 8:59

GoogleCodeExporter commented 8 years ago

Please see Issue 51 for a temporary proposed workaround.

Original comment by jon...@gmail.com on 11 Jun 2008 at 10:00

GoogleCodeExporter commented 8 years ago

Thanks, that was an oversight on my side. The solution that you propose looks 
good,
I'll integrate it asap.

Original comment by cast...@gmail.com on 11 Jun 2008 at 10:37

Changed state: Accepted

GoogleCodeExporter commented 8 years ago

Fixed as proposed in issue 51.

Original comment by cast...@gmail.com on 12 Jun 2008 at 1:21

Changed state: Fixed

dmsovetov / nvidia-texture-tools

Requesting colour dither discards alpha information #50