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# docs.GL

GLSL 4

# gl_SamplePosition

## Name

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

| 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
gl_SamplePosition | - | - | - | - | - | - | ✔ | ✔ | ✔ | ✔ | ✔ | ✔

## See Also

gl_SampleID, gl_SampleMask, gl_FragCoord

## 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. https://opencontent.org/openpub/.

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