1GL_EXT_texture_filter_anisotropic 2http://www.opengl.org/registry/specs/EXT/texture_filter_anisotropic.txt 3GL_EXT_texture_filter_anisotropic 4 GL_TEXTURE_MAX_ANISOTROPY_EXT 0x84FE 5 GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT 0x84FF 6