//-----------------------------------------------------------------------------
// Does a texture have alpha?
//-----------------------------------------------------------------------------
static bool DoesTextureUseAlpha( const char *pTextureName, const char *pMaterialName )
{
if ( IsX360() )
{
// not supporting
return false;
}
// Special textures start with '_'..
if ( pTextureName[0] == '_' )
return false;
// The texture name doubles as the relative file name
// It's assumed to have already been set by this point
// Compute the cache name
char pCacheFileName[MATERIAL_MAX_PATH];
Q_snprintf( pCacheFileName, sizeof( pCacheFileName ), "materials/%s.vtf", pTextureName );
CUtlBuffer buf;
FileHandle_t fileHandle = g_pFullFileSystem->Open( pCacheFileName, "rb" );
if ( fileHandle == FILESYSTEM_INVALID_HANDLE)
{
Warning( "Material \"%s\": can't open texture \"%s\"\n", pMaterialName, pCacheFileName );
return false;
}
// Check the .vtf for an alpha channel
IVTFTexture *pVTFTexture = CreateVTFTexture();
int nHeaderSize = VTFFileHeaderSize( VTF_MAJOR_VERSION );
buf.EnsureCapacity( nHeaderSize );
// read the header first.. it's faster!!
g_pFullFileSystem->Read( buf.Base(), nHeaderSize, fileHandle );
buf.SeekPut( CUtlBuffer::SEEK_HEAD, nHeaderSize );
// Unserialize the header
bool bUsesAlpha = false;
if (!pVTFTexture->Unserialize( buf, true ))
{
Warning( "Error reading material \"%s\"\n", pCacheFileName );
g_pFullFileSystem->Close(fileHandle);
}
else
{
if ( pVTFTexture->Flags() & (TEXTUREFLAGS_ONEBITALPHA | TEXTUREFLAGS_EIGHTBITALPHA) )
{
bUsesAlpha = true;
}
}
DestroyVTFTexture( pVTFTexture );
g_pFullFileSystem->Close( fileHandle );
return bUsesAlpha;
}
//-----------------------------------------------------------------------------
// These are methods to help with optimization of file access
//-----------------------------------------------------------------------------
void CVTFTexture::LowResFileInfo( int *pStartLocation, int *pSizeInBytes) const
{
// Once the header is read in, they indicate where to start reading
// other data, and how many bytes to read....
*pStartLocation = VTFFileHeaderSize();
if ((m_nLowResImageWidth == 0) || (m_nLowResImageHeight == 0))
{
*pSizeInBytes = 0;
}
else
{
*pSizeInBytes = ImageLoader::GetMemRequired( m_nLowResImageWidth,
m_nLowResImageHeight, m_LowResImageFormat, false );
}
}
