GL_ARB_texture_storage
http://www.opengl.org/registry/specs/ARB/texture_storage.txt
GL_ARB_texture_storage

	GL_TEXTURE_IMMUTABLE_FORMAT 0x912F
	void glTexStorage1D (GLenum target, GLsizei levels, GLenum internalformat, GLsizei width)
	void glTexStorage2D (GLenum target, GLsizei levels, GLenum internalformat, GLsizei width, GLsizei height)
	void glTexStorage3D (GLenum target, GLsizei levels, GLenum internalformat, GLsizei width, GLsizei height, GLsizei depth)
