| GL_SGIS_texture_filter4 | |
| http://oss.sgi.com/projects/ogl-sample/registry/SGIS/texture_filter4.txt | |
| void glGetTexFilterFuncSGIS (GLenum target, GLenum filter, GLfloat* weights) | |
| void glTexFilterFuncSGIS (GLenum target, GLenum filter, GLsizei n, const GLfloat* weights) |