FWIDTH(3G)                      [FIXME: manual]                     FWIDTH(3G)

NAME
       fwidth - return the sum of the absolute value of derivatives in x and y

DECLARATION
       genType fwidth(genType p);

       genType fwidthCoarse(genType p);

       genType fwidthFine(genType p);

PARAMETERS
       p
           Specifies the expression of which to take the partial derivative.

DESCRIPTION
       Available only in the fragment shader, these functions return the sum
       of the absolute derivatives in $x$ and $y$ using local differencing for
       the input argument p.  fwidth is equivalent to abs(dFdx(p)) +
       abs(dFdy(p)).  fwidthCoarse is equivalent to abs(dFdxCoarse(p)) +
       abs(dFdyCoarse(p)).  fwidthFine is equivalent to abs(dFdxFine(p)) +
       abs(dFdyFine(p)).

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 | 4.60 |
       +--------------+------+------+------+------+------+------+------+------+------+------+------+------+------+
       |fwidth        | <?>  | <?>  | <?>  | <?>  | <?>  | <?>  | <?>  | <?>  | <?>  | <?>  | <?>  | <?>  | <?>  |
       +--------------+------+------+------+------+------+------+------+------+------+------+------+------+------+
       |fwidthCoarse, |  -   |  -   |  -   |  -   |  -   |  -   |  -   |  -   |  -   |  -   |  -   | <?>  | <?>  |
       |fwidthFine    |      |      |      |      |      |      |      |      |      |      |      |      |      |
       +--------------+------+------+------+------+------+------+------+------+------+------+------+------+------+

SEE ALSO
       dFdx()

COPYRIGHT
       Copyright (C) 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/.

COPYRIGHT
       Copyright (C) 2011-2014 Khronos Group

[FIXME: source]                   03/14/2026                        FWIDTH(3G)