unpackUnorm - OpenGL 4 Reference Pages

## Name

unpackUnorm2x16, unpackUnorm4x8, unpackSnorm4x8 — unpack floating-point values from an unsigned integer

## Declaration

`vec2 unpackUnorm2x16(` | uint p`)`;

`vec2 unpackSnorm2x16(` | uint p`)`;

`vec4 unpackUnorm4x8(` | uint p`)`;

`vec4 unpackSnorm4x8(` | uint p`)`;

## Parameters

`p`

  Specifies an unsigned integer containing packed floating-point values.

## Description

`unpackUnorm2x16`, `unpackSnorm2x16`, `unpackUnorm4x8` and `unpackSnorm4x8` unpack single 32-bit unsigned integers, specified in the parameter `p` into a pair of 16-bit unsigned integers, four 8-bit unsigned integers or four 8-bit signed integers. Then, each component is converted to a normalized floating-point value to generate the returned two- or four-component vector.

The conversion for unpacked fixed point value f to floating-point is performed as follows:

- `packUnorm2x16`: `f / 65535.0`

- `packSnorm2x16`: ``clamp`(f / 32727.0, -1.0, 1.0)`

- `packUnorm4x8`: `f / 255.0`

- `packSnorm4x8`: ``clamp`(f / 127.0, -1.0, 1.0)`

The first component of the returned vector will be extracted from the least significant bits of the input; the last component will be extracted from the most significant bits.

## Version Support

| OpenGL Shading Language Version
--- | ---
Function Name | 1.10 | 1.20 | 1.30 | 1.40 | 1.50 | 3.30 | 4.00 | 4.10 | 4.20 | 4.30 | 4.40 | 4.50
unpackUnorm2x16 | - | - | - | - | - | - | ✔ | ✔ | ✔ | ✔ | ✔ | ✔
unpackSnorm2x16 | - | - | - | - | - | - | - | - | ✔ | ✔ | ✔ | ✔
unpackUnorm4x8 | - | - | - | - | - | - | ✔ | ✔ | ✔ | ✔ | ✔ | ✔
unpackSnorm4x8 | - | - | - | - | - | - | ✔ | ✔ | ✔ | ✔ | ✔ | ✔

## See Also

`packUnorm2x16`, `packUnorm4x8`, `packSnorm4x8`

## Copyright

Copyright © 2011-2014 Khronos Group. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999. http://opencontent.org/openpub/.