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

Array Textures

For certain applications, you may have a number of one- or two-dimensional textures that you might like to access simultaneously within the confines of a single draw call. For instance, suppose you’re authoring a game that features multiple characters of basically the same geometry, but each of which has its own costume. Or you might want to use multiple layers of texture for the character (diffuse color, a normal map, a specular intensity map, and a number of other attributes).

When using many textures like this, you would need to bind all of the required textures before the draw command. The calls to glBindTexture() for each draw call could have performance implications for the application if the texture objects needed to be ...