glClearIndexspecifiestheindexusedbyglCleartoclearthecolorindexbuffers.cisnotclamped.Rather,cisconvertedtoafixed-pointvaluewithunspecifiedprecisiontotherightofthebinarypoint.Theintegerpartofthisvalueisthenmaskedwith2m-1,wheremisthenumberofbitsinacolorindexstoredintheframebuffer.glClearIndex-specifyth