Specifies a texture coordinate.
Must be
GL_S
,
GL_T
,
GL_R
, or
GL_Q
.
pname
Specifies the symbolic name of the value(s) to be returned.
Must be either
GL_TEXTURE_GEN_MODE
or the name of one of the texture generation plane equations:
GL_OBJECT_PLANE
or
GL_EYE_PLANE
.