#pragma kernel CSMain
#define NUM_THREADS 8

float4 _Size;

RWStructuredBuffer<float> _Write;

[numthreads(NUM_THREADS,NUM_THREADS,NUM_THREADS)]
void CSMain (int3 id : SV_DispatchThreadID)
{

    int idx = id.x + id.y*_Size.x + id.z*_Size.x*_Size.y;
    
    float obstacle = 0;
    
    if(id.x-1 < 0) obstacle = 1;
    if(id.x+1 > (int)_Size.x-1) obstacle = 1;
    
    if(id.y-1 < 0) obstacle = 1;
    if(id.y+1 > (int)_Size.y-1) obstacle = 1;
    
    if(id.z-1 < 0) obstacle = 1;
    if(id.z+1 > (int)_Size.z-1) obstacle = 1;
    
    _Write[idx] = obstacle;
}