Environment: VC6, WIN32 (developed and tested on W2K SP2), DirectX 7
Due to private interest I wrote a small tool (MFC Dialog Application) to visualize alphablending and all combinations of possible attributes. The tool shows rotating earth with athmosphere. Earth and Athmosphere are spheres with textures. Based on the RenderStates D3DRENDERSTATE_SRCBLEND and D3DRENDERSTATE_SRCBLEND earth can be seen through the clouds. Material attributes can be changed also. Just try it out and have fun!
The zip containing the sources in big because of the graphics!