If you're experiencing white fog everywhere in the world (including indoors), then you likely need to enable GLSL.
1. Start regedit in your bottle (ie. run /opt/cxoffice/bin/cxrun or ~/cxoffice/bin/cxrun in a terminal, select the Guild Wars 2 bottle, and enter "regedit" in the command field)
2. Navigate to HKEY_CURRENT_USER\Software\Wine\Direct3D (creating the folders if they aren't there)
3. Select Edit -> New -> String
4. Enter "UseGLSL" as the name, and "enabled" as the value
Once this is done you should be good to go.
