[DirectX 7 Programmer's Reference] Directional Lights (98.6111111111111%)

Microsoft DirectX 7.0 > Direct3D > Direct3D Immediate Mode > Direct3D Immediate Mode Essentials > Lighting and Materials > Lights > Introduction to Light Objects

[DirectX 5 Programmer's Reference] Directional (30.9477195219739%)

DirectX Media > Direct3D Retained-Mode > Direct3D Retained-Mode Overview > Direct3D Retained-Mode Architecture > IDirect3DRMLight and IDirect3DRMLightArray Interfaces

[DirectX 3 Programmer's Reference] Directional (28.5291388039542%)

Direct3D > Retained-Mode Overview > Introduction to Direct3D Retained-Mode Objects > IDirect3DRMLight and IDirect3DRMLightArray Interfaces