---
name: "smoothstep"
section: "3clc"
platform: "linux"
package: "opencl-1.2-man-doc"
version: "1.0~svn33624-5.1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/smoothstep"
---

# smoothstep(3clc)

Step and interpolate.

## NAME

smoothstep - 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 *x* ≤ *edge0* and 1.0 if *x* ≥ *edge1* 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);
```

Results are undefined if *edge0* ≥ *edge1* or if *x*, *edge0* or *edge1* is a NaN.

## NOTES

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**(3clc)](/cl_khr_fp16/3clc.md), generic type name **gentype** may indicate **half** and **half{2\|3\|4\|8\|16}** as arguments and return values.

This function can be implemented using contractions such as [**mad**(3clc)](/mad/3clc.md) or [**fma**(3clc)](/fma/3clc.md).

## SPECIFICATION

**OpenCL Specification**\[1\]

## SEE ALSO

[**commonFunctions**(3clc)](/commonFunctions/3clc.md)

## AUTHORS

**The Khronos Group**

## COPYRIGHT

Copyright © 2007-2011 The Khronos Group Inc.\
 Permission is hereby granted, free of charge, to any person obtaining a copy of this software and/or associated documentation files (the "Materials"), to deal in the Materials without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Materials, and to permit persons to whom the Materials are furnished to do so, subject to the condition that this copyright notice and permission notice shall be included in all copies or substantial portions of the Materials.

## NOTES

- 1\.

  OpenCL Specification

  page 260, section 6.12.4 - Common Functions