[SOLVED] Unity compute shader: cycle through RWStructuredBuffer

Hi all, I'm new in shader programming, so I have question: how to make cycle which goes through RWStructuredBuffer?
I want to make molecules simulation so I have to make them attract each other, so I decided to make cycle which will do it. My attempt doesn't work, this is error:

invalid type for index - index must be a scalar, or a vector with the correct number of dimensions at kernel CSMain

Spoiler: My attemption to do it

Code (CSharp):

1. #pragma kernel CSMain
2.  
3. #include "Math.compute"
4.  
5. struct Molecule
6. {
7.     float mass;
8.     float3 position;
9.     float3 velocity;
10.     float diameter;
11. };
12.  
13. RWStructuredBuffer<Molecule> dataBuffer;
14.  
15. [numthreads(16,1,1)]
16. void CSMain (uint3 id : SV_DispatchThreadID)
17. {
18.     for( int i = 0; i < dataBuffer.Length; i ++ )
19.     {
20.         if (i != id)
21.         {
22.             dataBuffer[id].velocity = gravityConstant * (towards(dataBuffer[id].position, dataBuffer[i].position) * dataBuffer[id].mass * dataBuffer[i].mass / distance(dataBuffer[id.position], dataBuffer[i].position) ^ 2;
23.         }
24.     }
25. }

Contents of Math.compute.

Code (CSharp):

1. const float gravityConstant = 0.000000000067385;
2.  
3. float3 distance ( float3 a, float3 b)
4. {
5.     float3 vec = float3(a.x - b.x, a.y - b.y, a.z - b.z);
6.     return sqrt(vec.x * vec.x + vec.y * vec.y + vec.z * vec.z);
7. };
8.  
9. float3 towards ( float3 a, float3 b)
10. {
11.     return b - a;
12. };

After using google I found that id is a vector type variable so I have to list through buffer with some vector. What it should look like?

 

Not sure if this is the problem but at line 22 it looks like you try to make a float3 out of a float without proper casting...

Also cant see any initializer or some code that adds objects to your buffer.

 

In fact variable "i" should be uint3 type, but I don't know how to properly use it. What about initializer or some code that adds objects to buffer -- I made no it yet because I have problem with shader

 

I solved my problem -- to access RWStructuredBuffer I defined new uint3 type variable:

Code (CSharp):

1. for( int i = 0; i < (int)dataBuffer.Length; i++ )
2. {
3.     uint3 id2 = uint3(i,0,0);
4.     dataBuffer[id2.x] // And then write some code
5. }