GL_IMG_texture_compression_pvrtc
https://www.khronos.org/registry/OpenGL/extensions/IMG/IMG_texture_compression_pvrtc.txt
GL_IMG_texture_compression_pvrtc

	GL_COMPRESSED_RGB_PVRTC_4BPPV1_IMG 0x8C00
	GL_COMPRESSED_RGB_PVRTC_2BPPV1_IMG 0x8C01
	GL_COMPRESSED_RGBA_PVRTC_4BPPV1_IMG 0x8C02
	GL_COMPRESSED_RGBA_PVRTC_2BPPV1_IMG 0x8C03