Aha, now that's trickier. However, it will still be light-years easier to do this with PWM than building
32x32 = 1024 individual analog intensity controllers.
All in all, this is gonna take a LOT of hardware. Typically, people will set up a 2D array, say 8x8, and then
scan the rows and columns to turn on Leds say 8 at a time. The problem with this is that if you don't update
the Leds fast enough, then the intensities flicker. You have to update 50-60 times per sec to preclude
flicker.
However, you're probably not gonna find a single microcontroller with 32 PWM channels, and fast enough
to handle the entire 32x32 array. I would probably look at doing this with a small network of controllers,
say 16, with each controlling one 8x8 array.