GL_SGIS_point_line_texgen
http://www.opengl.org/registry/specs/SGIS/point_line_texgen.txt
	GL_EYE_DISTANCE_TO_POINT_SGIS 0x81F0
	GL_OBJECT_DISTANCE_TO_POINT_SGIS 0x81F1
	GL_EYE_DISTANCE_TO_LINE_SGIS 0x81F2
	GL_OBJECT_DISTANCE_TO_LINE_SGIS 0x81F3
	GL_EYE_POINT_SGIS 0x81F4
	GL_OBJECT_POINT_SGIS 0x81F5
	GL_EYE_LINE_SGIS 0x81F6
	GL_OBJECT_LINE_SGIS 0x81F7
