title: glTexImage2D - GL_TEXTURE_RECTANGLE_NV and compressed internal format
body: <p>I have modified a legacy code (OpenGL 2.1) which uses glTexImage2D with GL_TEXTURE_RECTANGLE_NV texture target. I have noticed that when I set some compressed internal format, for example GL_COMPRESSED_RGBA_S3TC_DXT5_EXT it doesn't work with GL_TEXTURE_RECTANGLE_NV (I get a white texture). I have tested other scenarios and everything works fine, i.e. GL_TEXTURE_2D with compressed internal format, GL_TEXTURE_RECTANGLE_NV with non-compressed internal format. Does it mean that GL_TEXTURE_RECTANGLE_NV can't be used with compressed formats ?</p>