SHP compression issue

Blade · Cyborg Commando **Joined**: 23 Dec 2003

I looked at the compression code in OpenRA the other day for TD/RA shp files and its at best a token effort to get bare compliance with the compression specification unless I'm looking in the wrong place. It doesn't even do full format80(LCW) compression which will result in much larger file sizes and doesn't have any code that I can see for format40(XORDelta) generation either.
I'm not sure if XCC can do much better to be honest and even the Red Horizon utilities only do full format80 with no format40 that I can see, but TD/RA era shp tools are no where near as good as they should be.

Matthias M. · Posted: Thu Mar 12, 2015 6:34 pm Post subject:

That is a kind of known problem. https://github.com/OpenRA/OpenRA/issues/2063 Help is appreciated as few people have the expert skills in that area.

DonutArnold · General **Joined**: 18 Jan 2005 **Location**: Finland

Split'd from Blender template topic.

Blade · Cyborg Commando **Joined**: 23 Dec 2003

I'm working on a larger project at the moment that has incidentally involved writing LCW and XORDelta code which from the limited testing done so far, is better than XCC. At some point I will get round to writing this into a tool for generating shp and probably wsa files for TD and RA.

The LCW code is based on the compressor the games themselves use and so can round trip WW compressed data, the XORDelta compressor is written against the Vladan Bato specs and appears to be slightly better than the WW compressor on some data. At some point the source will be released for this (its C++) and then it will be up to projects to port and integrate the code as necessary if they want to use it.