Reading floating point FITS files

Hello all, I am a software developer and I was assigned the task of
importing FITS files. Among the files that I have got are 32, 64
floating point files. I don't know how to extract the R,G,B values
from the flaoting point data.

To make it more clear: I am restricted to using a toolkit for
displaying the images. To be able to display the images correctly, I
have got to pass to the toolkit a buffer containing RGB data for each
pixel. So for each pixel I have to provide the toolkit with 3 bytes:
one for red, one for green, one for blue.

I don't know how is the RGB values stored in the 32, 64 floating point
data types of FITS files.