cgGetParameterOrdinalNumber
Keywords: cgGetParameterOrdinalNumber, NVIDIA, NVIDIA Cg Toolkit, Cg Toolkit, Shader, Shader Programming, GPU Shader Programming, GPU Program

> ## Name

> cgGetParameterOrdinalNumber - get a program parameter's ordinal number

> ## Synopsis

>     #include <Cg/cg.h>

>     int cgGetParameterOrdinalNumber( CGparameter param );

> ## Parameters

> param
>   The program parameter.

> ## Return Values

> Returns the ordinal number associated with a parameter. If the parameter is a constant (cgGetParameterVariability returns CG_CONSTANT) then 0 is returned and no error is generated.

> When cgGetParameterOrdinalNumber is passed an array, the ordinal number of the first array element is returned. When passed a struct, the ordinal number of first struct data member is returned.

> ## Description

> cgGetParameterOrdinalNumber returns an integer that represents the order in which the parameter was declared within the Cg program.

> Ordinal numbering begins at zero, starting with a program's first local leaf parameter. The subsequent local leaf parameters are enumerated in turn, followed by the program's global leaf parameters.

> ## Examples

> The following Cg program:

>     struct MyStruct { float a; sampler2D b; };
>     float globalvar1;
>     float globalvar2
>     float4 main(float2 position : POSITION,
>                 float4 color    : COLOR,
>                 uniform MyStruct mystruct,
>                 float2 texCoord : TEXCOORD0) : COLOR
>     {
>       /* etc ... */
>     }

> Would result in the following parameter ordinal numbering:

>     position    -> 0
>     color       -> 1
>     mystruct.a  -> 2
>     mystruct.b  -> 3
>     texCoord    -> 4
>     globalvar1  -> 5
>     globalvar2  -> 6

> ## Errors

> CG_INVALID_PARAM_HANDLE_ERROR is generated if param is not a valid parameter.

> ## History

> cgGetParameterOrdinalNumber was introduced in Cg 1.1.

> ## See Also

> cgGetParameterVariability