export const Kernel = 
{
    Corners:
    [
        [ 1,  1, -1],
        [ 1, -1, -1],
        [-1,  1, -1],
        [-1, -1, -1],
        [ 1,  1,  1],
        [ 1, -1,  1],
        [-1,  1,  1],
        [-1, -1,  1]
    ],
    Cardinal:
    [
        [ 1,  0,  0],
        [ 0,  1,  0],
        [-1,  0,  0],
        [ 0, -1,  0],
        [ 0,  0,  1],
        [ 0,  0, -1]
    ],

    Loop(inList, inVector, inHandler)
    {
        for(let i=0; i<inList.length; i++)
        {
            let delta = inList[i];
            if(inHandler(inVector[0]+delta[0], inVector[1]+delta[1], inVector[2]+delta[2]))
            {
                return;
            }
        }
    }
};
export const Region = 
{
    Create()
    {
        return {
            Voxels:[],
            Filled:[],
            Surface:[]
        };
    },
    CoordsToIndex(inX, inY, inZ)
    {
        return inX + inY*16 + inZ*256;
    },
    IndexToCoords(inI)
    {
        let zWhole = Math.floor(inI / 256);
        let zPart = inI % 256;
        let yWhole = Math.floor(zPart / 16);
        let yPart = zPart % 16;
        return [yPart, yWhole, zWhole];
    },
    Update(inRegion)
    {
        inRegion.Filled = [];
        inRegion.Surface = [];
        var i;
        for(i=0; i<inRegion.Voxels.length; i++)
        {
            if(inRegion.Voxels[i])
            {
                let coords = Region.IndexToCoords(i);
                Kernel.Loop(Kernel.Corners, coords, (inX, inY, inZ)=>
                {
                    let offsetIndex = Region.CoordsToIndex(inX, inY, inZ);
                    if(!inRegion.Voxels[offsetIndex])
                    {
                        inRegion.Surface.push(i);
                        return true;
                    }
                });
            }
        }
        console.log("looped over", i);
    }
};