2011 Khronos Group
gl_PatchVerticesIn 3G
gl_PatchVerticesIn contains the number of vertices in the current patch

## Declaration

`in int gl_PatchVerticesIn;`

## Description

Available only in the tessellation control and evaluation languages, `gl_PatchVerticesIn` contains the number of vertices in the input being processed by the shader. A single tessellation control or evaluation shader can read patches of differing sizes, and so th value of `gl_PatchVertexIn` may differ between patches.

## Version Support

#VARTABLECOLS#
#VARTABLEHEADER#
gl_PatchVerticesIn#newin40#

## See Also

gl_TessLevelOuter, gl_TessLevelInner, gl_TessCoord

## 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/.