Linker does not find libwebp functions

[Theverat]

Build fails with this error message:

Linking CXX executable ../../bin/luxcoreui
../../lib/libluxcore.so: undefined reference to `WebPPictureImportRGB'
../../lib/libluxcore.so: undefined reference to `WebPPictureFree'
../../lib/libluxcore.so: undefined reference to `WebPPictureImportRGBA'
../../lib/libluxcore.so: undefined reference to `WebPConfigInitInternal'
../../lib/libluxcore.so: undefined reference to `WebPEncode'
../../lib/libluxcore.so: undefined reference to `WebPGetInfo'
../../lib/libluxcore.so: undefined reference to `WebPPictureInitInternal'
../../lib/libluxcore.so: undefined reference to `WebPDecodeRGBA'
collect2: error: ld returned 1 exit status
make[3]: *** [bin/luxcoreui] Error 1
make[2]: *** [samples/luxcoreui/CMakeFiles/luxcoreui.dir/all] Error 2
make[1]: *** [samples/luxcoreui/CMakeFiles/luxcoreui.dir/rule] Error 2
make: *** [luxcoreui] Error 2
 !!! luxrays luxcore pyluxcore luxcoreui compilation failed

I guess there's a -lwebp or some similar linker flag missing - but where do I have to insert it? I guess it's in one of the many CMakeLists.txt files?
I have libwebp-dev and libwebp5 installed (I'm on Ubuntu 14.04).

[Dade916]

You are building the DLL version of LuxCore. This happen because of a bug in a condition checking. If you retry with the latest version and sources, it should work.
There may be still a problem in DLL compiling on your Linux but it wasn't what you were originally trying to do.

[Theverat]

Thanks for your help. By the way, it says that it's doing an OpenCL build even though I don't have "opencl" in the LuxCore source directory name - maybe that condition check is wrong, too?
I'd like to build without OpenCL on my laptop.

I did a git pull in both LinuxCompile and LuxCore repos, but I still get exactly the same error message as in the first post.
When I cd into LinuxCompile/LuxCore and run make I get these errors:

~/P/l/L/LuxCore [2]> make
[ 21%] Built target luxrays
[ 51%] Built target slg-core
[ 58%] Built target slg-film
[ 90%] Built target slg-kernels
[ 91%] Built target luxcore
[ 92%] Built target pyluxcore
Linking CXX executable ../../bin/luxcoredemo
/home/simon/Projekte/luxcore_build/LinuxCompile/target-64-sse2/lib/libOpenImageIOBase.a(webpinput.cpp.o): In function `OpenImageIO::v1_3::webp_pvt::WebpInput::open(std::string const&, OpenImageIO::v1_3::ImageSpec&)':
webpinput.cpp:(.text+0x83e): undefined reference to `WebPGetInfo'
webpinput.cpp:(.text+0xcbb): undefined reference to `WebPDecodeRGBA'
/home/simon/Projekte/luxcore_build/LinuxCompile/target-64-sse2/lib/libOpenImageIOBase.a(webpoutput.cpp.o): In function `OpenImageIO::v1_3::webp_pvt::WebpOutput::close()':
webpoutput.cpp:(.text+0x36): undefined reference to `WebPPictureFree'
/home/simon/Projekte/luxcore_build/LinuxCompile/target-64-sse2/lib/libOpenImageIOBase.a(webpoutput.cpp.o): In function `OpenImageIO::v1_3::webp_pvt::WebpOutput::open(std::string const&, OpenImageIO::v1_3::ImageSpec const&, OpenImageIO::v1_3::ImageOutput::OpenMode)':
webpoutput.cpp:(.text+0x2ad): undefined reference to `WebPPictureInitInternal'
webpoutput.cpp:(.text+0x2fe): undefined reference to `WebPConfigInitInternal'
/home/simon/Projekte/luxcore_build/LinuxCompile/target-64-sse2/lib/libOpenImageIOBase.a(webpoutput.cpp.o): In function `OpenImageIO::v1_3::webp_pvt::WebpOutput::write_scanline(int, int, OpenImageIO::v1_3::TypeDesc, void const*, long)':
webpoutput.cpp:(.text+0x2a52): undefined reference to `WebPPictureImportRGB'
webpoutput.cpp:(.text+0x2a61): undefined reference to `WebPEncode'
webpoutput.cpp:(.text+0x3021): undefined reference to `WebPPictureImportRGBA'
collect2: error: ld returned 1 exit status
make[2]: *** [bin/luxcoredemo] Error 1
make[1]: *** [samples/luxcoredemo/CMakeFiles/luxcoredemo.dir/all] Error 2
make: *** [all] Error 2

Edit: seems someone else had this problem before:
https://lists.blender.org/pipermail/bf-committers/2012-November/038297.html

[Dade916]

I fixed the OpenCL problem.

The Webp problem happens because you have installed the "libwebp-dev" (it is not installed by default, as far as I know). OpenImageIO will include Webp support if the dev headers/library is available. However OpenImageIO seems to not statically links to the Webp library even if explicitly asked for. It looks like an OIIO makefile bug.

As solution/workaround, just remove the "libwebp-dev" package and retry (it is a good idea to start with a fresh git clone anyway).

I can patch the OIIO CMakeFile to include the support only for a specific list of file format in order to be sure to not have a problem like your.

[Dade916]

Now it should work even if "libwebp-dev" package is installed.

[Theverat]

Cool, thanks.
After your last comment I did basically the same (commented out all lines containing webp in CMakeLists.txt of oiio) and it finally compiled.
Removing the libwebp-dev package did not help.