This example demonstrates powerful Porter-Duff composition used to create a nice noisy light effect.
Use W and S keys to adjust the level of "dust".
The FPS is limited to 30, because the effect is a little expensive and my computer couldn't handle 60 FPS. If you have a more powerful computer (which is quite likely), peek into the code and disable the limit.
Credit for the panda art goes to Ján Štrba.