OpenGL Programming Guide: The Official Guide to Learning OpenGL, Version 4.3, Eighth Edition

Using Textures

Once you have created and initialized a texture object and have placed image data into it, you may read from it using shaders in your application. As already noted, textures in shaders are represented as sampler variables of dimensioned sampler types. Each sampler variable is a combination of a set of image data represented by the texture object and a set of sampling parameters that are represented by a sampler object (or the texture’s own, internal sampler object). A texture is bound to a texture unit and a sampler object is bound to the corresponding sampler unit, and together they are used to read data from the texture’s images. This process is called sampling, and is performed using the texture built-in function in GLSL or ...