The key technical feature of Grand Theft Auto: Vice City is that it was built specifically for DirectX 8.1, which set it apart from its predecessor, GTA III (DirectX 7).
Grand Theft Auto: Vice City is a canonical example of early shader-model gaming. Its use of DirectX 8.1 was progressive in 2002—enabling real-time vehicle reflections and shadow volumes on mid-range hardware. However, the API’s hybrid nature (VS 1.1/PS 1.3) and lack of precision in texture addressing have rendered the native executable fragile on modern operating systems. gta vice city directx 8.1
Here are the specific visual features locked behind the "DirectX 8.1" requirement: The key technical feature of Grand Theft Auto:
This was the biggest leap. Instead of simple vertex lighting (DX7), Vice City used per-pixel shading. Its use of DirectX 8