iphone - Real time soft shadows without stencil buffers -

I'm really curious how the following is done

Actual The soft shadow on iPhone that stencil buffer is not available to get the time. It's running very fluid

Anyone have an idea?

Allows the hardware acceleration of stencil buffer shadows, but not required to display the shadow volume is. With a small number of bodies and light sources, the software can simulate the behavior of stencil buffer (but it will be much slower than hardware-accelerated implementation).

In addition, in other ways, the most often used for displaying shadows (a more deeply approach can be obtained), for which stencil buffer is not required. It is used for PS2 games, as well as Wii games, because those hardware also do not have stencil buffer.

And finally, under the circumstances of this particular game, the shadow algorithm can also be implemented as a simple tracing system, because there is no need to locate the floor, The form is calculated on 2D simple shapes (division and square). This can be the best way for this particular case.