func ClearIndex(c float32) {
	syscall.Syscall(gpClearIndex, 1, uintptr(math.Float32bits(c)), 0, 0)
}
func ClearIndex(c float32) {
	syscall.Syscall(gpClearIndex, 1, uintptr(math.Float32bits(c)), 0, 0)
}
func ClearIndex ( c float32 ) { syscall . Syscall ( gpClearIndex , 1 , uintptr ( math . Float32bits ( c ) ) , 0 , 0 ) }
// specify the clear value for the color index buffers
specify the clear value for the color index buffers