编译龙书的Demo出现这个问题，d3d11CodeSet\Chapter 6 Drawing in Direct3D\Box\
1. 添加到环境变量
fxc.exe在C:\Program Files (x86)\Microsoft DirectX SDK (June 2010)\Utilities\bin\x86
简单讲，将C:\Program Files (x86)\Microsoft DirectX SDK (June 2010)\Utilities\bin\x86\添加到PATH环境变量
2. 重启vs
重启vs，让环境变量生效
