//創建 DepthStencilSurface
    DXUTDeviceSettings d3dSettings = DXUTGetDeviceSettings();
 hr = pDev->CreateDepthStencilSurface( ENVMAPSIZE,
         ENVMAPSIZE,
         d3dSettings.pp.AutoDepthStencilFormat,
         D3DMULTISAMPLE_NONE,
         0,
         TRUE,
         & m_pSurfDepthCube,
         NULL );
 if( FAILED( hr))
  return hr;

 //創建立方體貼圖
    hr = pDev->CreateCubeTexture( ENVMAPSIZE,
                                        1,
                                        D3DUSAGE_RENDERTARGET,
                                        D3DFMT_A16B16G16R16F,
                                        D3DPOOL_DEFAULT,
                                        & m_pReflectCubeTex,
                                        NULL );
 if( FAILED( hr) )
  return hr;



3、把被反射物體渲染到立方體環境貼圖中

//------------------------------------------------------------
//desc: 渲染反射場景
//param: pDev 設備
//return: 是否創建成功
//------------------------------------------------------------
HRESULT GRenderMaterialProxy::RenderReflectScene(LPDIRECT3DDEVICE9 pDev)
{
 HRESULT hr;

 if( pDev == NULL)
  return E_FAIL;

 LPDIRECT3DSURFACE9 pSufRTBackup; //RenderTarget 備份
 LPDIRECT3DSURFACE9 pSufDSBackup; //DepthStencilSurface 備份

 pDev->GetRenderTarget( 0, & pSufRTBackup);

 if( SUCCEEDED( pDev->GetDepthStencilSurface( & pSufDSBackup) ) )
 {
  pDev->SetDepthStencilSurface( m_pSurfDepthCube);
 }

 //以反射物體為中心，設置視口投影矩陣
 LPDIRECT3DSURFACE9 pSurf;
 D3DXMATRIXA16 mView, mProj;
 D3DXMATRIXA16 mViewDir( * GCameraManager::GetInstance()->GetCamera()->GetViewMatrix() );
 mViewDir._41 = mViewDir._42 = mViewDir._43 = 0.0f;

    D3DXMatrixPerspectiveFovLH( &mProj, D3DX_PI * 0.5f, 1.0f, 0.01f, 10000.0f );

 std::vector< IRenderObject *>::iterator itRenderObj;

 //渲染Cube 6個表面
 for( int iFace = 0; iFace < 6; ++iFace)
 {
  //獲取立方體環境貼圖表面，并設為設備的渲染目標
  //注意：GetCubeMapSurface的第二個參數0表示獲取立方體環境貼圖的表面
  //如果是 n則表示獲取立方體環境貼圖的第n層表面
  V( m_pReflectCubeTex->GetCubeMapSurface( ( D3DCUBEMAP_FACES) iFace, 0, & pSurf));
  V( pDev->SetRenderTarget( 0, pSurf));

  mView = DXUTGetCubeMapViewMatrix( iFace);
  D3DXMatrixMultiply( & mView, & mViewDir, & mView);

  V( pDev->Clear( 0L, NULL, D3DCLEAR_ZBUFFER, 0x000000ff, 1.0f, 0L ));
  
  //渲染被反射物體
  for( itRenderObj = m_vpReflectObjects.begin(); itRenderObj != m_vpReflectObjects.end(); itRenderObj++)
   (*itRenderObj)->Render( pDev, & mView, & mProj);

  SAFE_RELEASE( pSurf);

 }

 if( pSufDSBackup)
 {
  pDev->SetDepthStencilSurface( pSufDSBackup); //恢復深度表面
  SAFE_RELEASE( pSufDSBackup);
 }

 pDev->SetRenderTarget( 0, pSufRTBackup); //恢復渲染目標
 SAFE_RELEASE( pSufRTBackup);

 return S_OK;
}
   

4、根據立方體環境貼圖確定反射物體的顏色(用HLSL實現）

 //渲染環境貼圖
 if( m_bEnableReflect)
  RenderReflectScene( pDev);

 D3DXMATRIXA16 mWorld, mView, mProj, mWorldView;
 CBaseCamera * pCamera = GCameraManager::GetInstance()->GetCamera();
 D3DXVECTOR4 vEyePos = D3DXVECTOR4(* GCameraManager::GetInstance()->GetCamera()->GetEyePt(), 0.0f);
 D3DXMATRIXA16 mEyePos;
 ::D3DXMatrixTranslation( & mEyePos, vEyePos.x, vEyePos.y, vEyePos.z);
 ::D3DXMatrixTranslation( & mWorld, 0.0f, 0.0f, 0.0f);

 mView = * pCamera->GetViewMatrix();
 mProj = * pCamera->GetProjMatrix();

 GVector4 * pLightDirList = G3DSceneManager::GetInstance()->GetLightDirList();
 UINT iLightCount = G3DSceneManager::GetInstance()->GetLightCount();

 //設置變化矩陣
 m_pEffect->SetMatrix("g_mWorld", &mWorld);
 m_pEffect->SetMatrix("g_mProj", &mProj);
 m_pEffect->SetMatrix("g_mView", &mView);

 m_pEffect->SetTexture("g_texReflect", m_pReflectCubeTex); //設置立方體環境貼圖
 m_pEffect->SetFloat("g_fReflectivity", m_fReflectivity); //設置反射率




( fx文件代碼如下）

extern matrix  g_mWorld;
extern matrix  g_mView;
extern matrix  g_mProj;

texture    g_texReflect;

float    g_fReflectivity = 0.9f;

samplerCUBE g_samReflect =
sampler_state
{
 Texture = <g_texReflect>;
 MinFilter = Linear;
 MagFilter = Linear;
 MipFilter = Linear;
};

void VS_Reflect( float4 iPos : POSITION,
 float3 iNor : NORMAL,
 out float4 oPos : POSITION,
 out float3 oEnvTex : TEXCOORD0 )
{
 matrix mWorldView = mul( g_mWorld, g_mView);
 oPos = mul( iPos, mWorldView);
 
 float3 vN = mul( iNor, mWorldView);
 vN = normalize( vN);
 
 float3 vEyeR = -normalize( oPos);
 
 float3 vRef;
 vRef = 2 * dot( vEyeR, vN) * vN - vEyeR;
 //vRef = reflect( vEyeR, vN);
 
 oEnvTex = vRef;
 
 oPos = mul( oPos, g_mProj);
}

float4 PS_Reflect( float3 iTex : TEXCOORD0 ) : COLOR
{
 float4 fColor = texCUBE( g_samReflect, iTex);
 fColor.x = fColor.x * g_fReflectivity;
 fColor.y = fColor.y * g_fReflectivity;
 fColor.z = fColor.z * g_fReflectivity;
 return fColor;  
}

technique Tec_RenderMaterial
{
 pass p0
 {
  vertexShader = compile vs_2_0 VS_Reflect();
  pixelShader = compile ps_2_0 PS_Reflect(); 
 }
}