gl_TessCoord - contains the coordinate of the vertex within the current patch

       Copyright © 2011-2014 Khronos Group

[FIXME: source]                                    11/18/2024                                   GL_TESSCOORD(3G)

       in vec3 gl_TessCoord ;.SH "DESCRIPTION"

       Available only in the tessellation cevaluation language, gl_TessCoord specifies the three component (u,
       v, w) vector identifying the position of the vertex being processed by the shader relative to the
       primitive being tessellated.

       gl_TessCoord - contains the coordinate of the vertex within the current patch

gl_TessLevelOuter(), gl_TessLevelInner(), gl_PatchVerticesIn()

       ┌──────────────┬───────────────────────────────────────────────────────────────────────────────────┐
       │              │        OpenGLShadingLanguageVersion                                            │
       ├──────────────┼──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┤
       │ Function     │ 1.10 │ 1.20 │ 1.30 │ 1.40 │ 1.50 │ 3.30 │ 4.00 │ 4.10 │ 4.20 │ 4.30 │ 4.40 │ 4.50 │
       │ Name         │      │      │      │      │      │      │      │      │      │      │      │      │
       ├──────────────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┤
       │ gl_TessCoord │  -   │  -   │  -   │  -   │  -   │  -   │  ✔   │  ✔   │  ✔   │  ✔   │  ✔   │  ✔   │
       └──────────────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┘