Hi,

I have been looking around a bit to figure out how to do the vertical zoom/scale used in many demos (two examples here)

http://www.youtube.com/watch?v=M0VEcNo8QdY&t=4m40s http://www.youtube.com/watch?v=--0altTjjFE&t=3m40s As I understand it this effect can be achieved by setting bpl1mod and bpl2mod to a negative value but the details is a bit unclear so I wonder if anyone could give some more hints how it works?

Thanks!