Building locally fails to find cpp src

[StephenHodgson]

I pulled this today to start contributing but I was having problems building locally.

./build_windows_x64.bat

From the errors it seems to be failing to find the firebase_cpp_sdk:

D:\Dev\Google\firebase-unity-sdk\windows_unity_seperate>cmake .. -A x64 -DPROTOBUF_SRC_ROOT_FOLDER=\=/  -DMONO_DIR="C:/Program Files/Mono/bin" -DUNITY_ROOT_DIR=\=/ -DOPENSSL_ROOT_DIR="C:/Program Files/OpenSSL-Win64" -DFIREBASE_UNITY_BUILD_TESTS=ON -DCMAKE_CONFIGURATION_TYPES=RelWithDebInfo -DFIREBASE_INCLUDE_UNITY=ON -DFIREBASE_UNI_LIBRARY=OFF
-- Building for: Visual Studio 16 2019
-- Selecting Windows SDK version 10.0.20348.0 to target Windows 10.0.19043.
-- The C compiler identification is MSVC 19.29.30133.0
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: C:/Program Files (x86)/Microsoft Visual Studio/2019/Enterprise/VC/Tools/MSVC/14.29.30133/bin/Hostx64/x64/cl.exe - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- The CXX compiler identification is MSVC 19.29.30133.0
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio/2019/Enterprise/VC/Tools/MSVC/14.29.30133/bin/Hostx64/x64/cl.exe - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Could NOT find PkgConfig (missing: PKG_CONFIG_EXECUTABLE) 
-- Found Mono: C:/Program Files/Mono/bin/mono.exe  
-- Auto detected latest Unity version: C:/Program Files/Unity/Hub/Editor/2020.3.17f1
-- Using Unity root directory: C:/Program Files/Unity/Hub/Editor/2020.3.17f1
-- UNITY_MONO_EXE is
-- UNITY_CSHARP_BUILD_EXE is
-- Found Unity: C:/Program Files/Unity/Hub/Editor/2020.3.17f1/Editor/Data/Managed/UnityEngine.dll  
-- Found SWIG: C:/Program Files/SWIG/swigwin-3.0.12/swig.exe (found version "3.0.12")  
-- Found SWIG: C:/Program Files/SWIG/swigwin-3.0.12/swig.exe (found suitable version "3.0.12", minimum required is "3.0.6")  
-- Using Unity root directory: C:/Program Files/Unity/Hub/Editor/2020.3.17f1
-- UNITY_MONO_EXE is C:/Program Files/Unity/Hub/Editor/2020.3.17f1/Editor/Data/MonoBleedingEdge/bin/mono.exe
-- UNITY_CSHARP_BUILD_EXE is C:/Program Files/Unity/Hub/Editor/2020.3.17f1/Editor/Data/MonoBleedingEdge/bin/xbuild.bat
CMake Warning:
  Manually-specified variables were not used by the project:

    FIREBASE_DOWNLOAD_DIR
    FIREBASE_EXTERNAL_PLATFORM


CMake Error at CMakeLists.txt:205 (add_subdirectory):
  The source directory

    D:/Dev/Google/firebase-unity-sdk/windows_unity_seperate/external/src/firebase_cpp_sdk

  does not contain a CMakeLists.txt file.

Example:

CMake Error at cmake/firebase_swig.cmake:116 (get_property):
  get_property could not find TARGET firebase_storage.  Perhaps it has not
  yet been created.
Call Stack (most recent call first):
  storage/CMakeLists.txt:40 (firebase_swig_add_library)

This same error repeats for each of the missing firebase modules

[waryard]

I had the same problem，is there any solution？

[AlmostMatt]

The Unity SDK depends on the C++ SDK.
In order to build from source, you must also check out the C++ SDK source (https://github.com/firebase/firebase-cpp-sdk)

By default, the builds scripts will search for the C++ SDK source in a folder named firebase-cpp-sdk that is in the same parent folder as the firebase-unity-sdk folder.
If the C++ SDK is in a different location, it must be specified with FIREBASE_CPP_SDK_DIR

[StephenHodgson]

Okay please update the documents to adequately describe this setup step