gecko-dev/gfx/angle/README.mozilla

This is the ANGLE project, from http://code.google.com/p/angleproject/

Current revision: r1561


== Applied local patches ==
In this order:
  angle-build-stdcall-alias.patch:
    Fix an issue GCC has with linking to undecorated stdcalls.
    
  angle-build-dedupe-debug-cpp-h.patch:
    Rename: "src/compiler/debug.{cpp,h}"
    To:     "src/compiler/compiler_debug.{cpp,h}"
    Repair includes accordingly.
    
  angle-build-dedupe-preproc-files.patch:
    Rename: "src/compiler/preprocessor/Diagnostics.cpp"
    To:     "src/compiler/preprocessor/PreprocessorDiagnostics.cpp"
    Rename: "src/compiler/preprocessor/DirectiveHandler.cpp"
    To:     "src/compiler/preprocessor/PreprocessorDirectiveHandler.cpp"
  
  angle-long-ident-spooky-hash.patch:
    Use Spooky Hash for long identifier hashing. See bug 676071.
  
  angle-faceforward-emu.patch:
    Adds emulation for faceforward(float,float,float), which is needed to
    prevent crashing on Mac+Intel. See bug 771406.

  angle-r1638.patch
    Adds uniform array index clamping on non-Windows platforms.
    Windows would require r1719, r1733, r1734.

  angle-cross-compilation.patch
    Fixes cross compilation on case sensitive OSes.

In addition to these patches, the Makefile.in files are ours, they're not present in
upsteam ANGLE. Therefore, changes made to the Makefile.in files should not be stored
in the local .patch files.


== How to do a clean-slate upgrade ==
1.  Backup our moz-specific files:
      README.mozilla
      Makefile.in
      *.patch
      src/libEGL/Makefile.in
      src/libGLESv2/Makefile.in

2.  $ rm -rf gfx/angle

3.  Copy the folder containing the angle rev you want onto gfx/angle.
    $ svn export -r <rev> <src> <moz-central>/gfx/angle 

4.  Fold our moz-specific files into this new angle folder. (Makefiles, README)
4a. Remove the unused directories. (test/, samples/, etc)

5.  Clear out the "Applied Local Patches" section above, since we're going to
    repopulate it.

6.  Re-apply the angle-build-*.patch files and record them above.

7.  Update the Makefile.in files with the current deps from the .gyp(i) files.

8.  Build. Fix things until it builds.

9.  Reapply the rest of the .patch files and record them above.

10. Try runs and reviews!


== Applying Diffs ==
In general:
$ patch -p1 -R < gfx/angle/angle-some-bug-fix.patch

SVN diffs however can be iffy. They don't seem to be completely compatible
with `patch`. Be aware that you'll likely get rejects whenever a file is
removed.



== How to do an incremental update ==
Same general idea here, but instead of nuking the ANGLE dir, we're going to
have to get a diff between revs from SVN, and deal with applying that. We
also naturally have to peel off our local patches before we can apply a diff
from upstream.

1. Unapply patches

Unapply them in reverse order, so iterate over the above list of applied patch
starting from the bottom. You most likely want to record these patch-unapply
operations as individual patches themselves, in order to re-apply patches later.

$ cd /path/to/mozilla-central

$ patch -p1 -R < gfx/angle/angle-some-bug-fix.patch
$ hg qnew unapply-angle-some-bug-fix.patch

2. Apply diff with new ANGLE version

Check at the top of this file what ANGLE revision we currently have. Let's say it's
r123. Check at the ANGLE Web site what recent revisions look like to figure what
revision seems safe. Let's say we want r456.

$ cd
$ svn checkout http://angleproject.googlecode.com/svn/trunk/ angleproject
$ cd angleproject
$ svn diff -r 123:456 > ~/angle-diff-from-123-to-456
$ cd /path/to/mozilla-central
$ cd gfx/angle
$ patch -p0 < ~/angle-diff-from-123-to-456
$ cd ../..
$ hg status
# hg add any new ANGLE files under gfx/angle
$ hg qnew angle-diff-from-123-to-456

3. Reapply patches

You may have to skip reapplying certain patches there, for example if they have
been integrated into ANGLE since our last update. The short patch descriptions above
in this file should help you make that decision.

If you have recorded the individual patch unapply operations in step 1 as separate
Mercurial patches, this will be easy, just apply the inverse patches now, in reverse
order:

$ patch -p1 -R < .hg/patches/unapply-angle-some-bug-fix.patch
$ hg status
# hg add any new ANGLE files under gfx/angle
$ hg qnew angle-some-bug-fix.patch

Note that here you need to proceed in the reverse order of what you did in step 1.

4. Update our Makefiles

Open your ANGLE diff file (~/angle-diff-from-123-to-456), search for GYP files
(e.g. build_angle.gyp), it's easy-to-read JSON. It may list additions of new files,
or removal of old files. You have to reflect this in our Makefiles:

gfx/angle/Makefile.in
gfx/angle/src/libEGL/Makefile.in
gfx/angle/src/libGLESv2/Makefile.in

The first one is our main Makefile. It has basically the ANGLE shader compiler.
Changes there will typically have to be applied also to the two other Makefiles.
These two other Makefiles are Windows-only and build the ANGLE GLES2-on-top-of-D3D
implementation.

5. Update patch files

Something like:

$ cp .hg/patches/angle-some-bug-fix.patch gfx/angle

For each patch that you reapplied.

If a patch was removed (not reapplied), remove the corresponding patch file.

6. Update this README.mozilla

You'll have to update at least the ANGLE revision number and probably the patch
list as well.

7. Push to Try

Make sure to test both Windows and non-Windows, and enable mochitest-1 in your
Try options. You may want reftest as well, as we have WebGL reftests.

8. Get reviews.

Typically, you would get review on your Makefiles patch, and any
new patches that you need to add to get this update to work.

You do not need a review for the ANGLE diff itself and for trivial updates of
existing patches.


== Visual Studio Solution Files ==
Ignore these. We don't use them anymore. We use custom Makefiles.


== Generated parser code==
Don't bother about that anymore. The parser is now generated and included in the ANGLE svn repo.