[VEX] Line Growing Effect(no sim)

Go:

Center out line growing;

Accelerate in the beginning then slow down and stop at the end.

All lines will move start from y=0 position, and stop at the same time in their own specific position.

(The purpose is to make a more smooth transform to the next effect which I will give a brief intro at the end.)

Notes:

i@primid and final position f@y

Separate motion to two parts -> X direction sin offset;

-> Y direction is accelerating, slowing down then stop.

-> X direction sin offset

-> Y direction is accelerating, slowing down then stop

Some functions references:

Growing lines overall network:

Pattern effect after line growing

Add @gattr based on group:

Create emitter group for generating following effects later. For example, particles, alpha...

Overall network: