U3D的shader移植到Creator遇到个问题

Creator 3.x
#1

各位大佬，U3D的shader中不同类型运算怎么转成cocos的呀？

IN.uv_NoiseTex += _MovementDirection * _Time.y / 2.0;
(float2+= float4* float)

不知道改成这样是不是对的

uv_NoiseTex += vec2(movementDirection * vec4(cc_time.x / 2.0));
#2

uv_NoiseTex += vec2(movementDirection) * (cc_time.x / 2.0);

#3

搞不懂，源shader那为啥把movementDirection设成float4呢，后两个数不就丢失了么

Properties
    {
       ...

        _MovementDirection ("Movement Direction", float) = (0, -1, 0, 1)
        
        ...
    }
#4

估计只是取xy当uv偏移量而已