GL_SGIS_sharpen_texture
http://www.opengl.org/registry/specs/gl/SGIS/sharpen_texture.txt
GL_SGIS_sharpen_texture
	void glGetSharpenTexFuncSGIS (GLenum target, GLfloat* points)
	void glSharpenTexFuncSGIS (GLenum target, GLsizei n, const GLfloat* points)