VEX实现物体沿线条流动

1. 

效果如下：

float offset = fit01(rand(@ptnum+654),0.5,1)*@Time*chf("speed") + rand(@ptnum+547);

int num = nprimitives(1);
vector pos = primuv(1,"P",@ptnum%num,offset%1);

@P = pos;

2.

效果如下： 

float min = detail(1,"min");
float max = detail(1,"max");

@`chs("name")` = fit(@`chs("name")`,min,max,0,1);

int num = nprimitives(1);
int prim = @ptnum%num;
float length = fit01(prim(1,"restlength",prim),0,0.7);

float offset = fit01(rand(@ptnum+654),0.5,1)*@Time*chf("speed")*(1-length) + rand(@ptnum+547);
vector pos = primuv(1,"P",@ptnum%num,offset%1);

@P = pos;