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我試圖使用libnoise library，這是Perlin雜點生成一個C++庫，在Visual Studio 2013教程3個鏈接到名爲noiseutils一個插件工具，它由一個的.cpp和.H，我在這裏舉行：「解析外部符號」錯誤2013
我有項目設置對包括文件夾（其內容如下圖所示）指出，和我的代碼看起來是這樣的。
#include "stdafx.h"
#include <noise/noise.h>
#include "noiseutils.h"
int _tmain(int argc, _TCHAR* argv[])
{
noise::module::Perlin myModule;
utils::NoiseMap heightMap;
utils::NoiseMapBuilderPlane heightMapBuilder;
heightMapBuilder.SetSourceModule(myModule);
heightMapBuilder.SetDestNoiseMap(heightMap);
heightMapBuilder.SetDestSize(256, 256);
heightMapBuilder.SetBounds(2.0, 6.0, 1.0, 5.0);
heightMapBuilder.Build();
utils::RendererImage renderer;
utils::Image image;
renderer.SetSourceNoiseMap(heightMap);
renderer.SetDestImage(image);
renderer.Render();
utils::WriterBMP writer;
writer.SetSourceImage(image);
writer.SetDestFilename("tutorial.bmp");
writer.WriteDestFile();
return 0;
}
所有這些代碼在其網站上提供的第三個教程中給出。 Visual Studio沒有抱怨說它找不到在所有這些代碼中指定的任何類或函數。但是，當我嘗試建立項目...
1>------ Build started: Project: libnoisetest, Configuration: Debug Win32 -- ----
1> libnoisetest.cpp
1>b:\visual studio\extra libraries\libnoise\include\noiseutils.h(1217): warning C4244: 'initializing' : conversion from 'const double' to 'float', possible loss of data
1>libnoisetest.obj : error LNK2019: unresolved external symbol "public: __thiscall noise::utils::GradientColor::~GradientColor(void)" ([email protected]@[email protected]@[email protected]) referenced in function "public: __thiscall noise::utils::RendererImage::~RendererImage(void)" ([email protected]@[email protected]@[email protected])
1>libnoisetest.obj : error LNK2019: unresolved external symbol "public: __thiscall noise::utils::NoiseMap::NoiseMap(void)" ([email protected]@[email protected]@[email protected]) referenced in function _wmain
1>libnoisetest.obj : error LNK2019: unresolved external symbol "public: __thiscall noise::utils::NoiseMap::~NoiseMap(void)" ([email protected]@[email protected]@[email protected]) referenced in function _wmain
1>libnoisetest.obj : error LNK2019: unresolved external symbol "public: __thiscall noise::utils::Image::Image(void)" ([email protected]@[email protected]@[email protected]) referenced in function _wmain
1>libnoisetest.obj : error LNK2019: unresolved external symbol "public: __thiscall noise::utils::Image::~Image(void)" ([email protected]@[email protected]@[email protected]) referenced in function _wmain
1>libnoisetest.obj : error LNK2019: unresolved external symbol "public: void __thiscall noise::utils::WriterBMP::WriteDestFile(void)" ([email protected]@[email protected]@@QAEXXZ) referenced in function _wmain
1>libnoisetest.obj : error LNK2019: unresolved external symbol "public: __thiscall noise::utils::NoiseMapBuilderPlane::NoiseMapBuilderPlane(void)" ([email protected]@[email protected]@[email protected]) referenced in function _wmain
1>libnoisetest.obj : error LNK2019: unresolved external symbol "public: virtual void __thiscall noise::utils::NoiseMapBuilderPlane::Build(void)" ([email protected]@[email protected]@@UAEXXZ) referenced in function _wmain
1>libnoisetest.obj : error LNK2019: unresolved external symbol "public: __thiscall noise::utils::RendererImage::RendererImage(void)" ([email protected]@[email protected]@[email protected]) referenced in function _wmain
1>libnoisetest.obj : error LNK2019: unresolved external symbol "public: void __thiscall noise::utils::RendererImage::Render(void)" ([email protected]@[email protected]@@QAEXXZ) referenced in function _wmain
1>B:\Visual Studio\_Projects\libnoisetest\Debug\libnoisetest.exe : fatal error LNK1120: 10 unresolved externals
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
總之，Visual Studio中找不到任何的東西在「noiseutils」，而它的實際建設。我在這裏做錯了什麼？
UPDATE：
由禁衛軍的建議複製noiseutils.cpp到我的源文件夾後，我得到這一套警告，和一個錯誤：
1>------ Build started: Project: libnoisetest, Configuration: Debug Win32 ------
1> noiseutils.cpp
1>b:\visual studio\extra libraries\libnoise\include\noiseutils.cpp(24): warning C4627: '#include <fstream>': skipped when looking for precompiled header use
1> Add directive to 'stdafx.h' or rebuild precompiled header
1>b:\visual studio\extra libraries\libnoise\include\noiseutils.cpp(26): warning C4627: '#include <noise/interp.h>': skipped when looking for precompiled header use
1> Add directive to 'stdafx.h' or rebuild precompiled header
1>b:\visual studio\extra libraries\libnoise\include\noiseutils.cpp(27): warning C4627: '#include <noise/mathconsts.h>': skipped when looking for precompiled header use
1> Add directive to 'stdafx.h' or rebuild precompiled header
1>b:\visual studio\extra libraries\libnoise\include\noiseutils.cpp(29): warning C4627: '#include "noiseutils.h"': skipped when looking for precompiled header use
1> Add directive to 'stdafx.h' or rebuild precompiled header
1>b:\visual studio\extra libraries\libnoise\include\noiseutils.cpp(1303): fatal error C1010: unexpected end of file while looking for precompiled header. Did you forget to add '#include "stdafx.h"' to your source?
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
我擡頭一看這個問題，並發現我可以簡單地使用預編譯頭文件來禁用noiseutils.cpp，因爲它不需要訪問stdafx。這樣，問題就解決了。
出於好奇不過，什麼是stdafx和它在Visual Studio項目中發揮什麼樣的作用？我是否需要禁用爲我的項目添加的任何源代碼禁用預編譯頭文件，以便忽略stdafx？
您需要noiseutils.cpp添加到您的項目。 – Praetorian
事後分析似乎很明顯......我會更新結果。 – ViggyNash
* stdafx.h中*是在爲您的項目預編譯頭（被編譯成* stdafx.cpp *）拉頭的默認名稱。在使用預編譯頭文件時，#include「stdafx.h」需要先於任何其他語句。因此，要麼禁用預編譯頭的項目範圍，或右鍵單擊在Solution Explorer * noiseutils.cpp *，進入屬性，以及地方在C/C++設置，預編譯頭頁上，可以讓你將其關閉的設置爲單個源文件。 – Praetorian