GL_EXT_texture_snorm
http://www.opengl.org/registry/specs/gl/EXT/texture_snorm.txt
GL_EXT_texture_snorm
	GL_RED_SNORM 0x8F90
	GL_RG_SNORM 0x8F91
	GL_RGB_SNORM 0x8F92
	GL_RGBA_SNORM 0x8F93
	GL_R8_SNORM 0x8F94
	GL_RG8_SNORM 0x8F95
	GL_RGB8_SNORM 0x8F96
	GL_RGBA8_SNORM 0x8F97
	GL_R16_SNORM 0x8F98
	GL_RG16_SNORM 0x8F99
	GL_RGB16_SNORM 0x8F9A
	GL_RGBA16_SNORM 0x8F9B
	GL_SIGNED_NORMALIZED 0x8F9C
	GL_ALPHA_SNORM 0x9010
	GL_LUMINANCE_SNORM 0x9011
	GL_LUMINANCE_ALPHA_SNORM 0x9012
	GL_INTENSITY_SNORM 0x9013
	GL_ALPHA8_SNORM 0x9014
	GL_LUMINANCE8_SNORM 0x9015
	GL_LUMINANCE8_ALPHA8_SNORM 0x9016
	GL_INTENSITY8_SNORM 0x9017
	GL_ALPHA16_SNORM 0x9018
	GL_LUMINANCE16_SNORM 0x9019
	GL_LUMINANCE16_ALPHA16_SNORM 0x901A
	GL_INTENSITY16_SNORM 0x901B