When seeking a Swift Shader 2.1 download, caution is advised. Because it is an older, open-source tool, it is often hosted on third-party file-sharing sites that may bundle malware or adware with the DLL.
Edit the registry or create a SwiftShader.ini file in the game folder: Swift Shader 2.1 Download
The original source is part of the TransGaming repository. Search GitHub for SwiftShader – but note that Google’s modern version is very different from 2.1. When seeking a Swift Shader 2