Portal:OpenGL Objects/Sampler Objects
A Sampler Object is an object that describes how texture objects are accessed from a Shader. These parameters include how accesses to the texture are to be filtered, whether comparison mode is active, texture coordinate wrapping, and so forth. Texture objects also have these parameters, but a sampler object bound to the same texture image unit will override them.
Unlike most OpenGL objects, you can modify the state of a sampler object without binding it.