Definitions for "bitmask "
a sequence of bits that can manipulate and/or read flags
a simple an efficient way to do that
A value which, when written out in binary, has a meaning assigned to each digit, which can be 0 or 1. This is a very efficient way of storing a number of flags in a small amount of memory. When viewed in decimal it is a single number resulting from adding up the values of the individual bits, worth 1, 2, 4, 8, 16, 32 and so on.
n. A mask, sense 1.
A pattern of bits for an IP address that determines how much of the IP address identifies the host and how much identifies the network. For example, if a bitmask of 24 were applied to the address 10.12.132.208, 10.12.132 identifies the network and the remainder of the address (1-254) can be used to specify individual machines on the 10.12.132 network. To learn more, see IP address and subnet mask. You can find a full discussion of the topic in these LiveSecurity editorials from the Foundations series: " Understanding IP Addresses and Binary," " Understanding Subnetting (Part 1)," and " Understanding Subnetting (Part 2)."
The bitmask library provides pixel-perfect collision detection for use in games and other applications. Functions are provided for building bitmasks and testing them for intersection. The routines can optionally provide a point of intersection and the number of overlapping pixels.