How to debug D3D9

Compile both Mesa-3D and Wine with CFLAGS and CXXFLAGS set to debug.

CFLAGS="-Og -ggdb -g -gdwarf-2 -gstrict-dwarf" CXXFLAGS="${CFLAGS}"

-Og is better than -O0 and disable optimalization which interferes with debug (gcc >= 4.8)
-ggdb, -g adds debug information to code
-gdwarf-2, -gstrict-dwarf limit DWARF version to 2. It's necessary for both, because wine support is limited to version 2.
you can also add -pg for profiling. Beware - may cause compilation issues.

Also configure Mesa-3D with

--enable-debug

Make sure, you have disabled striping debug symbols if you are using distribution packages, ebuild or AUR.

A problem can be located in either wine or Mesa. If it's in mesa, you'll need to use https://docs.mesa3d.org/envvars.html#nine-frontend-environment-variables

when you comparing logs from ALWAYS_SOFTWARE, is handy to get rid of different addr for diff, with this helps you

sed -i -e “s/0x[0-f]*/0x0/g” logfile.log*

For wine, WINEDEBUG=+d3dadapter9,+d3d9 should be enough.

You also may be interested in apitrace.

For apitrace to work, you need to use the no_external_dll branch of iXit/wine!
For debugging Windows applications you'll need to use APITrace compiled for Windows
The Windows version is almost always required for replaying

When uploading APITrace .trace file, please repack it with brotli (best compression → apitrace repack -b your_app.trace your_app-brotli.trace)