2011 Khronos Group
gl_SamplePosition 3G
gl_SamplePosition contains the location of the current sample within the current fragment

## Declaration

`in vec2 gl_SamplePosition;`

## Description

`gl_SamplePosition` is a fragment language input variable that contains the location within a fragment of the sample currently being processed. The x and y components of `gl_SamplePosition` contain the sub-pixel coordinate of the current sample and will have values in the range 0.0 to 1.0. The sub-pixel coordinates of the center of the pixel are always (0.5, 0.5). Any static use of `gl_SamplePosition` causes the entire fragment shader to be evaluated per-sample rather than per-fragment. When rendering to a non-multisample buffer, or if multisample rasterization is disabled, `gl_SamplePosition` will be (0.5, 0.5).

## Version Support

Variable | Version 1.10 | Version 1.20 | Version 1.30 | Version 1.40 | Version 1.50 | Version 3.30 | Version 4.00 | Version 4.10
--- | --- | --- | --- | --- | --- | --- | --- | ---
gl_SamplePosition | - | - | - | - | - | - | Y | Y

## See Also

gl_SampleID, gl_SampleMask, gl_FragCoord

## Copyright

Copyright 2011 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/.