Hello,
I was wondering if anyone could give me a good explanation for how to create bit fields in Processing/Java (assuming they work the same in this area). I've searched the internet, but most of the results involve C or some variant thereof, and leave me hopelessly confused.  : p

Also, what's the best method for viewing a single bit from a a bit field?

Cheers,
Gordon

it does work like java, which is to say it's kinda gross. for instance, to check the 2^2 bit:

int something = 2342345;
if ((something & 4) != 0) {
 // blah
}

in c/c++ that would be
if (something & 4) {
 // blah
}

the shift operator is also useful:
int bits0and1and4 = (1 << 4) | (1 << 1) | (1 << 0);

checking particular bits is most easily done with the shift operator:

boolean checkbit(int value, int index) {
 return (value & (1 << index)) != 0;
}

also the binary() and unbinary() functions are helpful to see what's going on.

you can also just use 'boolean' if you don't care about space, but keep in mind that a single boolean in java is the same size as an int (at least 32 bits).

or BitSet will let you play with zillions of em.

Quote:

both!

the eighth bit is the sign bit (java has no unsigned types), so a byte has the range -128 to 127. to convert it to a value between 0 and 255, use this:

byte b = -120;
int a = b & 0xff;

what's happening here is that you cast it to an int, which is 32 bits. doing this does a "sign extension" which means all 24 of the new bits are all 1s. then, you use the & operator to grab just the bottom 8 bits (0xff == 255 == 11111111). because it's still an int, it's now a number between 0 and 255.

if that doesn't make sense, read it six times, going more slowly each time. or draw a picture of it. or at least that's what worked for me.

or wikipedia has more:
http://en.wikipedia.org/wiki/Two's_complement