add (untested) SWIG interface file for Java bindings

[floe]

Starting point for fixing #417, not yet finished & untested. /cc @jonnius @xlz

[RyanGordon]

I like this approach. I've been working to get this to compile a golang binding. There are just a couple of incompatibilities, but the biggest thing is this:

../include/libfreenect2/libfreenect2.hpp:76: Warning 325: Nested struct not currently supported (ColorCameraParams ignored)
../include/libfreenect2/libfreenect2.hpp:82: Warning 325: Nested struct not currently supported (IrCameraParams ignored)

It seems like Swig doesn't support converting nested struct's at this time. We could always flatten it, or use something else

[floe]

@RyanGordon you can still pass the nested structs around as opaque objects, which should be sufficient for most use cases...

[RyanGordon]

@floe That is what I hoped too, but when I go to compile the generated golang code, I end up with this:

swig -c++ -DLIBFREENECT2_API -intgosize 64 -go -cgo freenect2.i
../include/libfreenect2/libfreenect2.hpp:76: Warning 325: Nested struct not currently supported (ColorCameraParams ignored)
../include/libfreenect2/libfreenect2.hpp:82: Warning 325: Nested struct not currently supported (IrCameraParams ignored)
../include/libfreenect2/libfreenect2.hpp:94: Warning 325: Nested struct not currently supported (Config ignored)
cd freenect && go get
Undefined symbols for architecture x86_64:
  "libfreenect2::Registration::Registration(libfreenect2::Freenect2Device::IrCameraParams, libfreenect2::Freenect2Device::ColorCameraParams)", referenced from:
      __wrap_new_Registration_libfreenect2_a7e1cfaf56dc8f3a in freenect2_wrap.cxx.o
  "libfreenect2::Registration::~Registration()", referenced from:
      __wrap_delete_Registration_libfreenect2_a7e1cfaf56dc8f3a in freenect2_wrap.cxx.o
  "libfreenect2::FrameListener::~FrameListener()", referenced from:
      SwigDirector_FrameListener::~SwigDirector_FrameListener() in freenect2_wrap.cxx.o
  "libfreenect2::PacketPipeline::PacketPipeline()", referenced from:
      __wrap_new_PacketPipeline_libfreenect2_a7e1cfaf56dc8f3a in freenect2_wrap.cxx.o
  "libfreenect2::Freenect2Device::~Freenect2Device()", referenced from:
      SwigDirector_Freenect2Device::~SwigDirector_Freenect2Device() in freenect2_wrap.cxx.o
  "libfreenect2::CpuPacketPipeline::CpuPacketPipeline()", referenced from:
      __wrap_new_CpuPacketPipeline_libfreenect2_a7e1cfaf56dc8f3a in freenect2_wrap.cxx.o
  "libfreenect2::Freenect2::openDevice(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&)", referenced from:
      __wrap_Freenect2_openDevice__SWIG_2_libfreenect2_a7e1cfaf56dc8f3a in freenect2_wrap.cxx.o
  "libfreenect2::Freenect2::openDevice(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, libfreenect2::PacketPipeline const*)", referenced from:
      __wrap_Freenect2_openDevice__SWIG_3_libfreenect2_a7e1cfaf56dc8f3a in freenect2_wrap.cxx.o
  "libfreenect2::Freenect2::openDevice(int)", referenced from:
      __wrap_Freenect2_openDevice__SWIG_0_libfreenect2_a7e1cfaf56dc8f3a in freenect2_wrap.cxx.o
  "libfreenect2::Freenect2::openDevice(int, libfreenect2::PacketPipeline const*)", referenced from:
      __wrap_Freenect2_openDevice__SWIG_1_libfreenect2_a7e1cfaf56dc8f3a in freenect2_wrap.cxx.o
  "libfreenect2::Freenect2::enumerateDevices()", referenced from:
      __wrap_Freenect2_enumerateDevices_libfreenect2_a7e1cfaf56dc8f3a in freenect2_wrap.cxx.o
  "libfreenect2::Freenect2::openDefaultDevice(libfreenect2::PacketPipeline const*)", referenced from:
      __wrap_Freenect2_openDefaultDevice__SWIG_1_libfreenect2_a7e1cfaf56dc8f3a in freenect2_wrap.cxx.o
  "libfreenect2::Freenect2::openDefaultDevice()", referenced from:
      __wrap_Freenect2_openDefaultDevice__SWIG_0_libfreenect2_a7e1cfaf56dc8f3a in freenect2_wrap.cxx.o
  "libfreenect2::Freenect2::getDeviceSerialNumber(int)", referenced from:
      __wrap_Freenect2_getDeviceSerialNumber_libfreenect2_a7e1cfaf56dc8f3a in freenect2_wrap.cxx.o
  "libfreenect2::Freenect2::getDefaultDeviceSerialNumber()", referenced from:
      __wrap_Freenect2_getDefaultDeviceSerialNumber_libfreenect2_a7e1cfaf56dc8f3a in freenect2_wrap.cxx.o
  "libfreenect2::Freenect2::Freenect2(void*)", referenced from:
      __wrap_new_Freenect2__SWIG_0_libfreenect2_a7e1cfaf56dc8f3a in freenect2_wrap.cxx.o
      __wrap_new_Freenect2__SWIG_1_libfreenect2_a7e1cfaf56dc8f3a in freenect2_wrap.cxx.o
  "libfreenect2::Registration::getPointXYZRGB(libfreenect2::Frame const*, libfreenect2::Frame const*, int, int, float&, float&, float&, float&) const", referenced from:
      __wrap_Registration_getPointXYZRGB_libfreenect2_a7e1cfaf56dc8f3a in freenect2_wrap.cxx.o
  "libfreenect2::Registration::apply(libfreenect2::Frame const*, libfreenect2::Frame const*, libfreenect2::Frame*, libfreenect2::Frame*, bool, libfreenect2::Frame*, int*) const", referenced from:
      __wrap_Registration_apply__SWIG_1_libfreenect2_a7e1cfaf56dc8f3a in freenect2_wrap.cxx.o
      __wrap_Registration_apply__SWIG_2_libfreenect2_a7e1cfaf56dc8f3a in freenect2_wrap.cxx.o
      __wrap_Registration_apply__SWIG_3_libfreenect2_a7e1cfaf56dc8f3a in freenect2_wrap.cxx.o
      __wrap_Registration_apply__SWIG_4_libfreenect2_a7e1cfaf56dc8f3a in freenect2_wrap.cxx.o
  "libfreenect2::Registration::apply(int, int, float, float&, float&) const", referenced from:
      __wrap_Registration_apply__SWIG_0_libfreenect2_a7e1cfaf56dc8f3a in freenect2_wrap.cxx.o
  "typeinfo for libfreenect2::FrameListener", referenced from:
      typeinfo for SwigDirector_FrameListener in freenect2_wrap.cxx.o
  "typeinfo for libfreenect2::Freenect2Device", referenced from:
      typeinfo for SwigDirector_Freenect2Device in freenect2_wrap.cxx.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [bin/freenect] Error 2

[floe]

Hm, this does look more like a linker problem to me? E.g. the fact that it can't find libfreenect2::Freenect2::enumerateDevices(). There have been some internal changes post-RC1, I haven't updated the SWIG file since. It may be possible that there's just some internal includes missing?

[floe]

#490 has been merged, do your Go bindings work now?

[RyanGordon]

@floe Not quite, it looks like we use a variable called "type" in a couple of places, but that is a reserved symbol in Go and SWIG isn't smart enough to rename it. Should I make a separate PR for that change?

[floe]

If it's part of a public interface, then it probably needs to be renamed. Otherwise, SWIG can also be told to explicitly rename certain identifiers.

[RyanGordon]

It looks like the "type" argument on "OnNewFrame" is causing the trouble. I was able to rename it by adding "#define type _type" to the SWIG file.

I'm now getting a bunch of linking errors. I'll try working through some of them but not sure how far I'll get tonight.

[xlz]

In order for this to be merged, we need at least one test case in Go or Java.

[floe]

I'd go with Java, as that would open up the route to Processing. Haven't done a lot with that recently, though.

[RyanGordon]

I've tried to get it working in Go but I keep getting stuck - Converting to go with SWIG is pretty messy and doesn't seem to compile due to reversed keywords being used and other syntax problems that seem to be not straightforward to fix

[floe]

Yeah, I think support for Go in SWIG is still pretty fresh, and Java is more mature. I'd suggest to get Java running first, and then see how other languages can be added.

[xlz]

@RyanGordon http://www.swig.org/Doc3.0/SWIGDocumentation.html#SWIG_rename_ignore ?