d attribute variable in the program
    object specified by <em class="parameter"><code>program</code></em> with a
    generic vertex attribute index. The name of the user-defined
    attribute variable is passed as a null terminated string in
    <em class="parameter"><code>name</code></em>. The generic vertex attribute index
    to be bound to this variable is specified by
    <em class="parameter"><code>index</code></em>. When
    <em class="parameter"><code>program</code></em> is made part of current st