最后一類是渲染函數(shù)，類CDXUTMesh重載了兩個(gè)渲染函數(shù)Render()，其作用都是用來渲染當(dāng)前的網(wǎng)格模型。所不同的是，第一個(gè)函數(shù)用在固定函數(shù)流水線中，第二個(gè)函數(shù)用在可編程流水線技術(shù)中，這兩個(gè)函數(shù)的最后兩個(gè)參數(shù)用于指定是否渲染網(wǎng)格模型中的不透明和半透明部分。
首先來看第一個(gè)Render()函數(shù)：
HRESULT CDXUTMesh::Render( LPDIRECT3DDEVICE9 pd3dDevice, bool bDrawOpaqueSubsets, bool bDrawAlphaSubsets )
{
if( NULL == m_pMesh )
return E_FAIL;
// Frist, draw the subsets without alpha
if( bDrawOpaqueSubsets )
{
for( DWORD i=0; i<m_dwNumMaterials; i++ )
{
if( m_bUseMaterials )
{
if( m_pMaterials[i].Diffuse.a < 1.0f )
continue;
pd3dDevice->SetMaterial( &m_pMaterials[i] );
pd3dDevice->SetTexture( 0, m_pTextures[i] );
}
m_pMesh->DrawSubset( i );
}
}
// Then, draw the subsets with alpha
if( bDrawAlphaSubsets && m_bUseMaterials )
{
for( DWORD i=0; i<m_dwNumMaterials; i++ )
{
if( m_pMaterials[i].Diffuse.a == 1.0f )
continue;
// Set the material and texture
pd3dDevice->SetMaterial( &m_pMaterials[i] );
pd3dDevice->SetTexture( 0, m_pTextures[i] );
m_pMesh->DrawSubset( i );
}
}
return S_OK;
}
代碼簡(jiǎn)潔明了，首先繪制不透明的網(wǎng)格（alpha == 1.0f），接著繪制半透明的網(wǎng)格（alpha
!= 1.0f）。
接著來看第二個(gè)Render()函數(shù)：
HRESULT CDXUTMesh::Render( ID3DXEffect *pEffect,
D3DXHANDLE hTexture, D3DXHANDLE hDiffuse, D3DXHANDLE hAmbient,
D3DXHANDLE hSpecular, D3DXHANDLE hEmissive, D3DXHANDLE hPower,
bool bDrawOpaqueSubsets, bool bDrawAlphaSubsets )
{
if( NULL == m_pMesh )
return E_FAIL;
UINT cPasses;
// Frist, draw the subsets without alpha
if( bDrawOpaqueSubsets )
{
pEffect->Begin( &cPasses, 0 );
for( UINT p = 0; p < cPasses; ++p )
{
pEffect->BeginPass( p );
for( DWORD i=0; i<m_dwNumMaterials; i++ )
{
if( m_bUseMaterials )
{
if( m_pMaterials[i].Diffuse.a < 1.0f )
continue;
if( hTexture )
pEffect->SetTexture( hTexture, m_pTextures[i] );
// D3DCOLORVALUE and D3DXVECTOR4 are data-wise identical.
// No conversion is needed.
if( hDiffuse )
pEffect->SetVector( hDiffuse, (D3DXVECTOR4*)&m_pMaterials[i].Diffuse );
if( hAmbient )
pEffect->SetVector( hAmbient, (D3DXVECTOR4*)&m_pMaterials[i].Ambient );
if( hSpecular )
pEffect->SetVector( hSpecular, (D3DXVECTOR4*)&m_pMaterials[i].Specular );
if( hEmissive )
pEffect->SetVector( hEmissive, (D3DXVECTOR4*)&m_pMaterials[i].Emissive );
if( hPower )
pEffect->SetFloat( hPower, m_pMaterials[i].Power );
pEffect->CommitChanges();
}
m_pMesh->DrawSubset( i );
}
pEffect->EndPass();
}
pEffect->End();
}
// Then, draw the subsets with alpha
if( bDrawAlphaSubsets )
{
pEffect->Begin( &cPasses, 0 );
for( UINT p = 0; p < cPasses; ++p )
{
pEffect->BeginPass( p );
for( DWORD i=0; i<m_dwNumMaterials; i++ )
{
if( m_bUseMaterials )
{
if( m_pMaterials[i].Diffuse.a == 1.0f )
continue;
if( hTexture )
pEffect->SetTexture( hTexture, m_pTextures[i] );
// D3DCOLORVALUE and D3DXVECTOR4 are data-wise identical.
// No conversion is needed.
if( hDiffuse )
pEffect->SetVector( hDiffuse, (D3DXVECTOR4*)&m_pMaterials[i].Diffuse );
if( hAmbient )
pEffect->SetVector( hAmbient, (D3DXVECTOR4*)&m_pMaterials[i].Ambient );
if( hSpecular )
pEffect->SetVector( hSpecular, (D3DXVECTOR4*)&m_pMaterials[i].Specular );
if( hEmissive )
pEffect->SetVector( hEmissive, (D3DXVECTOR4*)&m_pMaterials[i].Emissive );
if( hPower )
pEffect->SetFloat( hPower, m_pMaterials[i].Power );
pEffect->CommitChanges();
}
m_pMesh->DrawSubset( i );
}
pEffect->EndPass();
}
pEffect->End();
}
return S_OK;
}
代碼也是相當(dāng)簡(jiǎn)潔明了，首先繪制不透明網(wǎng)格，接著繪制半透明網(wǎng)格。在繪制時(shí)遍歷所有的通道，并設(shè)置紋理，材質(zhì)的漫反射光、環(huán)境光、鏡面反射光、自發(fā)光、鏡面反射光指數(shù)。