This step applies only to stencil index groups. If MAP_STENCIL is enabled, then the index is looked up in the PIXEL_MAP_S_TO_S table (otherwise, the index is not looked up). The table must have entries for some integer n, and the integer part of the index is ANDed with , producing a value. This value addresses the table, and the value in the table replaces the index. The floating-point table value is first rounded to a fixed-point value with unspecified precision.