HLSL(High Level Shader Language) is provided with DirectX9 for developing and debugging shaders in a C-like language. This capability is in addition to the assembly language shader capability that is used to generate vertex shaders, pixel shaders, and effects which began with DirectX 8.0.

The high-level shader language supports the development of shaders with C-like functions. The language will support many standard language features such as functions, expressions, statements, standard data types, user-designed data types, and preprocessor directives. With the invention of programmable vertex and pixel shaders in DirectX8.0 DirectX was almost equivalent with Open GL in terms of performance. HLSL will lead DirectX in the API battle in the coming days! And it is the developers who will decide which API will win the war!