Texturing is enabled or disabled using the generic Enable and Disable commands, respectively, with the symbolic constant TEXTURE_1D or TEXTURE_2D to enable the one-dimensional or two-dimensional texture, respectively. If both one- and two-dimensional textures are enabled, the two-dimensional texture is used. If all texturing is disabled, a rasterized fragment is passed on unaltered to the next stage of the GL (although its texture coordinates may be discarded). Otherwise, a texture value is found according to the parameter values of the currently bound texture image of the appropriate dimensionality using the rules given in sections 3.8.1 and 3.8.2. This texture value is used along with the incoming fragment in computing the texture function indicated by the currently bound texture environment. The result of this function replaces the incoming fragment's R, G, B, and A values. These are the color values passed to subsequent operations. Other data associated with the incoming fragment remain unchanged, except that the texture coordinates may be discarded.
The required state is two bits indicating whether each of one- or two-dimensional texturing is enabled or disabled. In the initial state, all texturing is disabled.