void FShaderCache::Save(FArchive& Ar, const map<FGuid, FShader*>& InShaders)
{
Ar << m_nPlatform;
// serialize the global shader crc
UINT NumShaderBuilderCRC = m_mapShaderBuilderCRC.size();
Ar << NumShaderBuilderCRC;
map<FShaderBuilder*, DWORD>::iterator it;
for( it = m_mapShaderBuilderCRC.begin(); it != m_mapShaderBuilderCRC.end(); ++it )
{
FShaderBuilder* ShaderBuilder = it->first;
Ar << ShaderBuilder;
Ar << it->second;
}
// serialize the global shaders
UINT NumShaders = InShaders.size();
Ar << NumShaders;
for( map<FGuid, FShader*>::const_iterator it = InShaders.begin(); it != InShaders.end(); ++it )
{
FShader* Shader = it->second;
// shader builder的序列化，在加载时可用于检测此类型的shader是否仍存在
FShaderBuilder* ShaderBuilder = Shader->GetShaderBuilder();
FGuid ShaderId = Shader->GetId();
Ar << ShaderBuilder << ShaderId;
// 占个位先。。。应该记录序列化此shader的结束位置
INT SkipOffset = Ar.Tell();
Ar << SkipOffset;
Shader->Serialize(Ar);
INT EndOffset = Ar.Tell();
Ar.Seek(SkipOffset); // 定位回之前位置
Ar << EndOffset; // 记录此shader的结束位置
Ar.Seek(EndOffset); // 定位结束位置，继续下一个shader的序列化
}
}
void FShaderCache::Load(FArchive& Ar)
{
Ar << m_nPlatform;
UINT NumShaderBuilderCRC = 0;
Ar << NumShaderBuilderCRC;
for(UINT IndexBuilder = 0; IndexBuilder < NumShaderBuilderCRC; ++IndexBuilder)
{
FShaderBuilder* ShaderBuilder = NULL;
Ar << ShaderBuilder;
DWORD CRC = 0;
Ar << CRC;
if( ShaderBuilder )
{
m_mapShaderBuilderCRC[ShaderBuilder] = CRC;
}
}
// serialize the global shaders
UINT NumShaders = 0;
UINT NumDesertedShaders = 0;
UINT NumRedundantShaders = 0;
vector<FString> OutdatedShaderBuilders;
Ar << NumShaders;
for(UINT IndexShader = 0; IndexShader < NumShaders; ++IndexShader)
{
FShaderBuilder* ShaderBuilder = NULL;
FGuid ShaderId;
Ar << ShaderBuilder << ShaderId;
INT SkipOffset = 0;
Ar << SkipOffset;
if( !ShaderBuilder )
{
++NumDesertedShaders;
Ar.Seek(SkipOffset); // this shader builder doesn't exist any more, skip the shader
}
else
{
DWORD CurrentCRC = 0;
DWORD SavedCRC = 0;
// 比较当前与之前版本的CRC，检测是否有改动
CurrentCRC = ShaderBuilder->GetSourceCRC();
map<FShaderBuilder*, DWORD>::const_iterator it = m_mapShaderBuilderCRC.find(ShaderBuilder);
if( it != m_mapShaderBuilderCRC.end() )
{
SavedCRC = it->second;
}
FShader* Shader = ShaderBuilder->FindShaderById(ShaderId);
if( Shader )
{
++NumRedundantShaders;
Ar.Seek(SkipOffset); // has already exist, skip it
}
else if( SavedCRC != CurrentCRC )
{
++NumDesertedShaders;
Ar.Seek(SkipOffset);
if( SavedCRC != 0 ) // denote SHADER BUILDER exists, but it has changed
{
OutdatedShaderBuilders.push_back(ShaderBuilder->GetShaderName());
}
}
else
{
// the shader is compatiable, create it
Shader = ShaderBuilder->ConstructSerialization();
UBOOL bShaderHasOutdatedParameters = Shader->Serialize(Ar);
if( bShaderHasOutdatedParameters )
{
ShaderBuilder->UnregisterShader(Shader);
delete Shader;
}
check(Ar.Tell() == SkipOffset);
}
}
}
if( OutdatedShaderBuilders.size() > 0 )
{
debugf(TEXT("Skip %d outdated FShaderBuilder"), OutdatedShaderBuilders.size());
for(UINT IndexBuilder = 0; IndexBuilder < OutdatedShaderBuilders.size(); ++IndexBuilder)
{
debugf(TEXT(" %s"), OutdatedShaderBuilders.at(IndexBuilder).c_str());
}
}
if( NumShaders > 0 )
{
debugf(TEXT("Loaded %d shaders (%d deserted, %d redundant)"), NumShaders, NumDesertedShaders, NumRedundantShaders);
}
}
