错误LNK2005已经定义 - 编译运行后编译时出错

Question

我正在尝试关注Riemer's DirectX with C++ tutorial。

我做了一些改变，例如在这里我已经在一个单独的文件（tdirect.cpp/tdirect.h）中使我的InitializeDevice()函数。

当我按F5编译并运行时，程序完美运行。但是，当我改变一个值（例如0xff00ffff到0xff0000ff - 青色到蓝色）没有选择“重建”选项我在我的控制台中得到一串错误，使我无法编译程序。你可以想象这很烦人。就好像它正在编译tdirect.cpp两次。

下面是tdirect.cpp，tdirect.h的源代码，和相关部分从main.cpp（tdirect.h是仅从main.cpp包括在内，basicvertex.h仅从tdirect.cpp包括）

tdirect.cpp：

#include "tdirect.h" 
#include "basicvertex.h" 

IDirect3D9 *pD3D; 
D3DPRESENT_PARAMETERS D3DParams; 

LPDIRECT3DDEVICE9 InitializeDevice(HWND Wnd) 
{ 
    pD3D = Direct3DCreate9(D3D_SDK_VERSION); 
    if (pD3D == NULL) 
    { 
     MessageBox(Wnd, "DirectX is not installed.", "No DirectX!", MB_OK); 
     return NULL; 
    } 

    ZeroMemory(&D3DParams, sizeof(D3DPRESENT_PARAMETERS)); 

    D3DParams.Windowed = TRUE; 
    D3DParams.SwapEffect = D3DSWAPEFFECT_DISCARD; 
    D3DParams.BackBufferFormat = D3DFMT_UNKNOWN; 

    LPDIRECT3DDEVICE9 pDevice; 
    if (FAILED(pD3D->CreateDevice(D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, Wnd, D3DCREATE_HARDWARE_VERTEXPROCESSING, &D3DParams, &pDevice))) 
    { 
     if (FAILED(pD3D->CreateDevice(D3DADAPTER_DEFAULT, D3DDEVTYPE_REF, Wnd, D3DCREATE_SOFTWARE_VERTEXPROCESSING, &D3DParams, &pDevice))) 
     { 
      MessageBox(Wnd, "Failed to create reference device.", "No software device!", MB_OK); 
     } 
     else { 
      MessageBox(Wnd, "Falling back to software mode.", "No hardware device!", MB_OK); 
     } 
    } 

    return pDevice; 
} 

LPDIRECT3DVERTEXBUFFER9 vBuffer; 
void Init(LPDIRECT3DDEVICE9 pDevice) 
{ 
    BASICVERTEX Vertices[3]; 
    Vertices[0].x = 150; 
    Vertices[0].y = 100; 
    Vertices[0].weight = 1; 
    Vertices[0].colour = 0xffff0000; 

    Vertices[1].x = 350; 
    Vertices[1].y = 100; 
    Vertices[1].weight = 1; 
    Vertices[1].colour = 0xff00ff00; 

    Vertices[2].x = 250; 
    Vertices[2].y = 300; 
    Vertices[2].weight = 1; 
    Vertices[2].colour = 0xff00ffff; 

    if (FAILED(pDevice->CreateVertexBuffer(sizeof(BASICVERTEX)*3, 0, D3DFVF_XYZRHW | D3DFVF_DIFFUSE, D3DPOOL_DEFAULT, &vBuffer, NULL))) 
    { 
     MessageBox(NULL, "Failed to create vertex buffer", "Fail", MB_OK); 
    } 
    else { 
     void* pVertices; 
     if (FAILED(vBuffer->Lock(0, sizeof(BASICVERTEX)*3, (void**)&pVertices, 0))) 
     { 
      MessageBox(NULL, "Failed to lock vertex buffer", "Fail", MB_OK); 
     } 
     else { 
      memcpy(pVertices, Vertices, sizeof(BASICVERTEX)*3); 
      vBuffer->Unlock(); 
     } 
    } 
} 

void DrawScene(LPDIRECT3DDEVICE9 pDevice) 
{ 
    pDevice->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0,0,0), 1.0f, 0); 
    pDevice->BeginScene(); 

    pDevice->SetStreamSource(0, vBuffer, 0, sizeof(BASICVERTEX)); 
    pDevice->SetFVF(D3DFVF_XYZRHW | D3DFVF_DIFFUSE); 
    pDevice->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 1); 

    pDevice->EndScene(); 
    pDevice->Present(NULL, NULL, NULL, NULL); 
} 

tdirect.h：

#pragma once 
#include <Windows.h> 

main.cpp包括部分：

#include <Windows.h> 

#include "dxheader.h" 
#include "tdirect.cpp" 

编译器错误：

1>Debug\tdirect.obj : warning LNK4042: object specified more than once; extras ignored 
1>main.obj : error LNK2005: "struct IDirect3DDevice9 * __cdecl InitializeDevice(struct HWND__ *)" ([email protected]@[email protected]@[email protected]@@Z) already defined in tdirect.obj 
1>main.obj : error LNK2005: "void __cdecl Init(struct IDirect3DDevice9 *)" ([email protected]@[email protected]@@Z) already defined in tdirect.obj 
1>main.obj : error LNK2005: "void __cdecl DrawScene(struct IDirect3DDevice9 *)" ([email protected]@[email protected]@@Z) already defined in tdirect.obj 
1>main.obj : error LNK2005: "struct IDirect3DVertexBuffer9 * vBuffer" ([email protected]@[email protected]@A) already defined in tdirect.obj 
1>main.obj : error LNK2005: "struct _D3DPRESENT_PARAMETERS_ D3DParams" ([email protected]@[email protected]@A) already defined in tdirect.obj 
1>main.obj : error LNK2005: "struct IDirect3D9 * pD3D" ([email protected]@[email protected]@A) already defined in tdirect.obj 
1>C:\Users\me\Documents\Visual Studio 2010\Projects\DirectX\Debug\DXStuff.exe : fatal error LNK1169: one or more multiply defined symbols found 

感谢提前:)

Answer 1

您正在从main.cpp中包含实现文件，因此它将再次添加函数。你可以这样做：

#include "tdirect.cpp" 

相反，你需要创建一个头文件与函数原型，所以你可以参考他们...

你已经在你的“tdirect.h”这些定义（这是什么main.cpp应该包括）？在主的#include “tdirect.cpp”：

LPDIRECT3DDEVICE9 InitializeDevice(HWND Wnd); 

等等