Getting out the r-channel from a argb-uint?

Question

i have an argb value in the parameter of a function and the function needs to get rid of the agb values and only keep the r. How would you do that? thank-you

Answer 1

That is done with bitwise shifting and bitwise AND.

The uint in a 32 bit integer. Each of the A,R,G,B takes up 8 of its bits(one byte). And they appear I the same order as the name implies A,R,G,B

To get out b you just need to mask out all the other bits with a bitwise AND statement.

a=argb&255 because 255 in binary is 11111111, it only keeps the needed bits.

for g you first need to shift the bits then do the above. g=argb>>8&255

r is same but shift 16 bits

r=argb>>16&255

and a a=argb>>24&255

Hope that helps

Answer 2

here's more information on it: http://www.adobe.com/devnet/flash/articles/bitwise_operators_print.html