Step and interpolate.

gentype smoothstep(gentype edge0,
                   gentype edge1,
                   gentype x)

gentypef smoothstep(float edge0,
                    float edge1,
                    gentypef x)

gentyped smoothstep(double edge0,
                    double edge1,
                    gentyped x)
gentype smoothstep (half edge0,
              half edge1,
              gentype x)   // if half extension enabled

Description

Returns 0.0 if xedge0 and 1.0 if xedge1 and performs smooth Hermite interpolation between 0 and 1 when edge0 < x < edge1. This is useful in cases where you would want a threshold function with a smooth transition.

This is equivalent to:

          gentype t;
          t = clamp((x - edge0) / (edge1 - edge0), 0, 1);
          return t * t * (3 - 2 * t);

For the forms that take an edge0 of type other than half or halfn, results are undefined if edge0edge1 or if x, edge0 or edge1 is a NaN. For the forms that are enabled with the cl_khr_fp16 extension, results are undefined if edge0edge1.

Notes

These all operate component-wise. The description is per-component. The generic type name gentype is used to indicate that the function can take float, float2, float3, float4, float8, float16, double, double2, double3, double4, double8, or double16 as the type for the arguments.

The generic type name gentypef is used to indicate that the function can take float, float2, float3, float4, float8, or float16 as the type for the arguments.

The generic type name gentyped is used to indicate that the function can take double, double2, double3, double4, double8, or double16 as the type for the arguments.

The built-in common functions are implemented using the round to nearest even rounding mode.

If extended with cl_khr_fp16, generic type name gentype may indicate half and half{2|3|4|8|16} as arguments and return values.

The mix and smoothstep functions can be implemented using contractions such as mad or fma.

Also see

Specification