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2009年4月 (17)

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建立自己的3D静态模型文件

跟着我一步一步来吧（我的思路和过程）。
我有一个能画出微软例子中tiger.x的工程，其中创建Mesh的代码片断如下（代码中有一些变量在.h文档中定义的）：
HRESULT CMyMesh::Create( LPDIRECT3DDEVICE9 pDevice, string MeshFile )
{
if( pDevice == NULL )
return E_FAIL;

    LPD3DXBUFFER pD3DXMtrlBuffer;
    if( FAILED( D3DXLoadMeshFromX( MeshFile.c_str(), D3DXMESH_SYSTEMMEM, pDevice, NULL, &pD3DXMtrlBuffer, NULL, &NumOfMaterials, &Mesh ) ) )
      return E_FAIL;

    D3DXMATERIAL* d3dxMaterials = (D3DXMATERIAL*)pD3DXMtrlBuffer->GetBufferPointer();
    MeshMaterials = new D3DMATERIAL9[NumOfMaterials];
    MeshTextures = new LPDIRECT3DTEXTURE9[NumOfMaterials];

    for( DWORD i = 0; i < NumOfMaterials_; i ++ )
    {
      MeshMaterials[i] = d3dxMaterials[i].MatD3D;
      MeshMaterials[i].Ambient = MeshMaterials[i].Diffuse;
      MeshTextures[i] = NULL;
      if( d3dxMaterials[i].pTextureFilename != NULL && lstrlen(d3dxMaterials[i].pTextureFilename) > 0 )
      {
        if( FAILED( D3DXCreateTextureFromFile( pDevice, d3dxMaterials[i].pTextureFilename, &MeshTextures[i] ) ) )
          return E_FAIL;
      }
    }

pD3DXMtrlBuffer->Release();
return S_OK;
}

画这个Mesh的代码如下：
void CMyMesh::Render( LPDIRECT3DDEVICE9 pDevice )
{
    for( DWORD i = 0; i < NumOfMaterials; i ++ )
    {
      pDevice->SetMaterial( &MeshMaterials[i] );
      pDevice->SetTexture( 0, MeshTextures[i] );

      Mesh->DrawSubset( i );
    }
}

我们先想办法替换DrawSubset函数，代码如下：
void CMyMesh::Render( LPDIRECT3DDEVICE9 pDevice )
{
  LPDIRECT3DVERTEXBUFFER9 pVertexBuffer;
  LPDIRECT3DINDEXBUFFER9 pIndexBuffer;
  DWORD dwNumBytesPerVertex;
  DWORD dwFVF;
  DWORD dwNumVertex;
  DWORD dwFaces;
  Mesh->GetVertexBuffer(&pVertexBuffer);
  Mesh->GetIndexBuffer(&pIndexBuffer);
  dwNumBytesPerVertex = Mesh->GetNumBytesPerVertex();
  dwFVF = Mesh->GetFVF();
  dwNumVertex = Mesh->GetNumVertices();
  dwFaces = Mesh->GetNumFaces();

  pDevice->SetStreamSource(0, pVertexBuffer, 0, dwNumBytesPerVertex);
  pDevice->SetFVF(dwFVF);
  pDevice->SetTexture(0, MeshTextures[0]);
  pDevice->SetMaterial(&MeshMaterials[0]);
  pDevice->SetIndices(pIndexBuffer);
  pDevice->DrawIndexedPrimitive(D3DPT_TRIANGLELIST, 0, 0, dwNumVertex, 0, dwFaces);
}

虽然MeshTextures和MeshMaterials处有点问题，但是我们知道了画tiger.x的时候都需要什么东西：
VB,IB,NumBytesPerVertex,FVF,NumVertex,Faces,Texture,Material
那么我们将这些东西保存到文件中，不就和.x文件目的相同了么，并且可以绕过D3DXMesh了。那么这些东西怎么得到呢：我修改了Create部分的代码：

HRESULT CMyMesh::Create( LPDIRECT3DDEVICE9 pDevice, string MeshFile )
{
if( pDevice == NULL )
return E_FAIL;

    for( DWORD i = 0; i < NumOfMaterials_; i ++ )
    {
      MeshMaterials_[i] = d3dxMaterials[i].MatD3D;
      MeshMaterials_[i].Ambient = MeshMaterials_[i].Diffuse;
      MeshTextures_[i] = NULL;
      if( d3dxMaterials[i].pTextureFilename != NULL && lstrlen(d3dxMaterials[i].pTextureFilename) > 0 )
      {
        FILE* fp;
          int nLen = 0;
          char* pBuf;
          if(fp=fopen( d3dxMaterials[i].pTextureFilename, "rb" )) {
          fseek(fp,0,SEEK_END);
          nLen = ftell(fp);
          fseek(fp,0,SEEK_SET);
          pBuf = new char[nLen];
          fread(pBuf,1,nLen,fp);
          fclose(fp);
        }
        HRESULT hr = D3DXCreateTextureFromFileInMemory(D3DDevice,pBuf,nLen,&MeshTextures[i]);
        delete [] pBuf;

    //HRESULT hr = D3DXCreateTextureFromFile( D3DDevice_, d3dxMaterials[i].pTextureFilename, &MeshTextures_[i] );
        if( FAILED( hr ) )
          return E_FAIL;
      }
    }

    //下面是增加的内容
    FILE* fp;
    if( ( fp = fopen("tiger.o","w") ) != NULL ) {
   LPDIRECT3DVERTEXBUFFER9 pVertexBuffer;
   LPDIRECT3DINDEXBUFFER9 pIndexBuffer;
   D3DVERTEXBUFFER_DESC desc;
   D3DINDEXBUFFER_DESC idesc;

   Mesh->GetVertexBuffer(&pVertexBuffer);
   Mesh->GetIndexBuffer(&pIndexBuffer);
   pVertexBuffer->GetDesc( &desc );
   pIndexBuffer->GetDesc( &idesc );

   VOID* pVBData = NULL;
   VOID* pIBData = NULL;

   pVertexBuffer->Lock( 0, 0, (VOID**)&pVBData, 0 );
   pIndexBuffer->Lock( 0, 0, (VOID**)&pIBData, 0 );

   DWORD dwFVF = Mesh->GetFVF();
   DWORD dwNumBytesPerVertex = Mesh->GetNumBytesPerVertex();
   DWORD dwNumFaces = Mesh->GetNumFaces();

   //怎么样？该有的都有了吧，要怎么保存就看你的了
   //这段代码显然不完善，你需要自己去完善它
   //有人说了你光考虑了Mesh，还有多AnimationSet等等东西呢？
   //这里本来就只是建立静态模型，当然没有AnimationSet啦。动画的部分我后面在写吧。

   pVertexBuffer->UnLock();
   pIndexBuffer->UnLock();

   fclose(fp);
    }
    //增加结束