PartialPrecision

// D3DXSHADER_PARTIALPRECISION
//   Force all computations in resulting shader to occur at partial precision.
//   This may result in faster evaluation of shaders on some hardware.

이 옵션을 사용하면 shader의 float의 정밀도를 반으로 줄인다.
그럼으로 인해서 shader들의 연산 속도를 높인다.



// 그 외 기타 shader 옵션
//----------------------------------------------------------------------------
// D3DXSHADER flags:
// -----------------
// D3DXSHADER_DEBUG
//   Insert debug file/line/type/symbol information.
//
// D3DXSHADER_SKIPVALIDATION
//   Do not validate the generated code against known capabilities and
//   constraints.  This option is only recommended when compiling shaders
//   you KNOW will work.  (ie. have compiled before without this option.)
//   Shaders are always validated by D3D before they are set to the device.
//
// D3DXSHADER_SKIPOPTIMIZATION
//   Instructs the compiler to skip optimization steps during code generation.
//   Unless you are trying to isolate a problem in your code using this option
//   is not recommended.
//
// D3DXSHADER_PACKMATRIX_ROWMAJOR
//   Unless explicitly specified, matrices will be packed in row-major order
//   on input and output from the shader.
//
// D3DXSHADER_PACKMATRIX_COLUMNMAJOR
//   Unless explicitly specified, matrices will be packed in column-major
//   order on input and output from the shader.  This is generally more
//   efficient, since it allows vector-matrix multiplication to be performed
//   using a series of dot-products.
//
// D3DXSHADER_PARTIALPRECISION
//   Force all computations in resulting shader to occur at partial precision.
//   This may result in faster evaluation of shaders on some hardware.
//
// D3DXSHADER_FORCE_VS_SOFTWARE_NOOPT
//   Force compiler to compile against the next highest available software
//   target for vertex shaders.  This flag also turns optimizations off,
//   and debugging on. 
//
// D3DXSHADER_FORCE_PS_SOFTWARE_NOOPT
//   Force compiler to compile against the next highest available software
//   target for pixel shaders.  This flag also turns optimizations off,
//   and debugging on.
//
// D3DXSHADER_NO_PRESHADER
//   Disables Preshaders. Using this flag will cause the compiler to not
//   pull out static expression for evaluation on the host cpu
//
// D3DXSHADER_AVOID_FLOW_CONTROL
//   Hint compiler to avoid flow-control constructs where possible.
//
// D3DXSHADER_PREFER_FLOW_CONTROL
//   Hint compiler to prefer flow-control constructs where possible.
//
//----------------------------------------------------------------------------