[DirectX 6 Programmer's Reference] Range-Based Fog (37.2297297297297%)

DirectX Foundation > Direct3D Immediate Mode > Direct3D Immediate Mode Essentials > Common Techniques and Special Effects > Fog

[DirectX October 2006 Documentation] Range (18.536036036036%)

DirectX SDK > Introducing DirectX 9.0 > Namespaces > Microsoft.DirectX.Direct3D > Classes > Light > Properties