Linker errors

[JohnGarrison78]

I'm trying to build a simple Hello World program that uses Diligent Engine, but I'm getting a whole lot of linker errors. Can someone tell me if I'm missing some libraries that are needed to link correctly? It may be a bit messy. I've tried a lot to fix it. Claude and ChatGPT made a lot of useless suggestions as well. The samples work fine, but they're built alongside the engine and I'm trying to link it with a separate project.

cmake_minimum_required(VERSION 3.12)
project(Igloo)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

# Set the root directory
set(CHILLYWADDLER_ROOT "${CMAKE_CURRENT_SOURCE_DIR}/..")

# SDL2 setup
set(SDL2_DIR "${CHILLYWADDLER_ROOT}/ThirdParty/SDL2")
set(SDL2_INCLUDE_DIR "${SDL2_DIR}/include")

if(WIN32)
    if(CMAKE_SIZEOF_VOID_P EQUAL 8)
        set(SDL2_LIB_DIR "${SDL2_DIR}/lib/windows/x64")
        set(SDL2_BIN_DIR "${SDL2_DIR}/bin/x64")
    else()
        set(SDL2_LIB_DIR "${SDL2_DIR}/lib/windows/x86")
        set(SDL2_BIN_DIR "${SDL2_DIR}/bin/x86")
    endif()
    set(SDL2_LIBRARY "${SDL2_LIB_DIR}/SDL2.lib")
    set(SDL2MAIN_LIBRARY "${SDL2_LIB_DIR}/SDL2main.lib")
    set(SDL2_DLL "${SDL2_BIN_DIR}/SDL2.dll")
elseif(APPLE)
    set(SDL2_LIB_DIR "${SDL2_DIR}/lib/macos")
    set(SDL2_LIBRARY "${SDL2_LIB_DIR}/libSDL2.dylib")
else() # Linux
    set(SDL2_LIB_DIR "${SDL2_DIR}/lib/linux")
    set(SDL2_LIBRARY "${SDL2_LIB_DIR}/libSDL2.so")
endif()

include_directories(${SDL2_INCLUDE_DIR})

# Diligent Engine setup
set(DILIGENT_ENGINE_DIR "${CHILLYWADDLER_ROOT}/ThirdParty/DiligentEngine")
set(DILIGENT_CORE_DIR "${DILIGENT_ENGINE_DIR}/DiligentCore")
set(DILIGENT_FX_DIR "${DILIGENT_ENGINE_DIR}/DiligentFX")

include_directories(
        ${DILIGENT_CORE_DIR}
        ${DILIGENT_FX_DIR}
)

# IMGUI setup
set(IMGUI_DIR "${CHILLYWADDLER_ROOT}/ThirdParty/imgui-docking")
set(IMGUI_SOURCES
        ${IMGUI_DIR}/imgui.cpp
        ${IMGUI_DIR}/imgui_demo.cpp
        ${IMGUI_DIR}/imgui_draw.cpp
        ${IMGUI_DIR}/imgui_tables.cpp
        ${IMGUI_DIR}/imgui_widgets.cpp
)
add_library(imgui STATIC ${IMGUI_SOURCES})
target_include_directories(imgui PUBLIC ${IMGUI_DIR})

# Set the path for pre-built Diligent Engine libraries
if(WIN32)
    add_definitions(-DPLATFORM_WIN32=1)
    if(CMAKE_BUILD_TYPE STREQUAL "Debug")
        add_definitions(-D_DEBUG)
        set(DILIGENT_LIB_DIR "${DILIGENT_ENGINE_DIR}/cmake-build-debug-visual-studio")
    else()
        set(DILIGENT_LIB_DIR "${DILIGENT_ENGINE_DIR}/cmake-build-release-visual-studio")
    endif()
    set(LIB_PREFIX "")
    set(LIB_SUFFIX ".lib")
    set(DLL_SUFFIX ".dll")
elseif(APPLE)
    add_definitions(-DPLATFORM_MACOS=1)
    if(CMAKE_BUILD_TYPE STREQUAL "Debug")
        add_definitions(-D_DEBUG)
        set(DILIGENT_LIB_DIR "${DILIGENT_ENGINE_DIR}/cmake-build-debug-xcode")
    else()
        set(DILIGENT_LIB_DIR "${DILIGENT_ENGINE_DIR}/cmake-build-release-xcode")
    endif()
    set(LIB_PREFIX "lib")
    set(LIB_SUFFIX ".a")
    set(DLL_SUFFIX ".dylib")
else() # Linux
    add_definitions(-DPLATFORM_LINUX=1)
    if(CMAKE_BUILD_TYPE STREQUAL "Debug")
        add_definitions(-D_DEBUG)
        set(DILIGENT_LIB_DIR "${DILIGENT_ENGINE_DIR}/cmake-build-debug-linux")
    else()
        set(DILIGENT_LIB_DIR "${DILIGENT_ENGINE_DIR}/cmake-build-release-linux")
    endif()
    set(LIB_PREFIX "lib")
    set(LIB_SUFFIX ".a")
    set(DLL_SUFFIX ".so")
endif()

# Function to find library
function(find_diligent_library OUT_VAR LIB_NAME)
    file(GLOB_RECURSE LIB_PATH
            "${DILIGENT_LIB_DIR}/**/${LIB_PREFIX}${LIB_NAME}${LIB_SUFFIX}"
    )
    if(LIB_PATH)
        list(GET LIB_PATH 0 FIRST_LIB_PATH)  # In case multiple matches are found, use the first one
        set(${OUT_VAR} ${FIRST_LIB_PATH} PARENT_SCOPE)
        message(STATUS "Found ${LIB_NAME} at ${FIRST_LIB_PATH}")
    else()
        message(FATAL_ERROR "Could not find ${LIB_NAME} library")
    endif()
endfunction()

# Your project executable
add_executable(${PROJECT_NAME} main.cpp)

# Define the list of Diligent libraries
set(DILIGENT_LIBS
        Diligent-Common
        Diligent-GraphicsEngine
        Diligent-GraphicsTools
        DiligentFX
)

if(WIN32)
    list(APPEND DILIGENT_LIBS
            Diligent-GraphicsEngineD3D12-static
    )
elseif(APPLE)
    list(APPEND DILIGENT_LIBS
            Diligent-GraphicsEngineOpenGL-static
    )
else()
    list(APPEND DILIGENT_LIBS
            Diligent-GraphicsEngineVK-static
    )
endif()

# Link libraries
if(WIN32)
    target_link_libraries(${PROJECT_NAME}
            PRIVATE
            ${SDL2_LIBRARY}
            ${SDL2MAIN_LIBRARY}
            d3d12.lib
            dxgi.lib
            d3dcompiler.lib
            imgui
    )
else()
    target_link_libraries(${PROJECT_NAME}
            PRIVATE
            ${SDL2_LIBRARY}
            imgui
    )
endif()

# Link Diligent libraries
foreach(LIB ${DILIGENT_LIBS})
    find_diligent_library(LIB_PATH ${LIB})
    target_link_libraries(${PROJECT_NAME} PRIVATE ${LIB_PATH})
endforeach()

if(MSVC)
    set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /MD")
    set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} /MDd")
endif()

Here are the last few linker errors. You'd be scrolling forever if I pasted them all:

Diligent-Common.lib(BasicFileStream.cpp.obj) : error LNK2001: unresolved external symbol "public: static void __cdecl Diligent::BasicFileSystem::ReleaseFile(class Diligent::BasicFile *)" (?ReleaseFile@BasicFileSystem@Diligent@@SAXPEAVBasicFile@2@@Z)
Diligent-Common.lib(BasicFileStream.cpp.obj) : error LNK2001: unresolved external symbol "public: unsigned __int64 __cdecl Diligent::StandardFile::GetSize(void)" (?GetSize@StandardFile@Diligent@@QEAA_KXZ)
Diligent-Common.lib(BasicFileStream.cpp.obj) : error LNK2001: unresolved external symbol "public: bool __cdecl Diligent::StandardFile::Write(void const *,unsigned __int64)" (?Write@StandardFile@Diligent@@QEAA_NPEBX_K@Z)
Diligent-Common.lib(BasicFileStream.cpp.obj) : error LNK2001: unresolved external symbol "public: bool __cdecl Diligent::StandardFile::Read(struct Diligent::IDataBlob *)" (?Read@StandardFile@Diligent@@QEAA_NPEAUIDataBlob@2@@Z)
Diligent-Common.lib(BasicFileStream.cpp.obj) : error LNK2001: unresolved external symbol "public: bool __cdecl Diligent::StandardFile::Read(void *,unsigned __int64)" (?Read@StandardFile@Diligent@@QEAA_NPEAX_K@Z)
Igloo.exe : fatal error LNK1120: 79 unresolved externals

[TheMostDiligent]

It looks like you are not using Diligent's CMake files, so the projects do not pull their dependencies.
To fix the errors you listed, you need to add Diligent-TargetPlatform

[JohnGarrison78]

Thanks! That's at least a step in the right direction. I should have mentioned it in my post. I saw the BuildSettings and TargetPlatform in the Diligent CMake file and tried to include them, but they don't seem to exist. I figured maybe they were something specific to the engine itself. I built Diligent with CLion and don't see them in the list of targets. But I am hopeful that I can get this resolved if I can figure out where they are or how to build them.
EDIT: I now see it's an alias of Win32Platform, but adding that didn't fix the problem.

[TheMostDiligent]

I saw the BuildSettings and TargetPlatform in the Diligent CMake file and tried to include them, but they don't seem to exist

You need to add_subdirectory(DiligentCore) - this will create all the necessary CMake targets.