It's more fun to compute!

gistfile1.glsl

    // compute weights
    // this is just a packed LUT of the tap weights; phrasing it like this
    // gives *much* better code than using a table.
    uint lane = gl_LocalInvocationID.x;
    int shift = int(min(lane, 7-lane)) * 8;
    ivec2 weights = bitfieldExtract(ivec2(0x0e182434, 0x08040100), shift, 8);
    weights = (lane < 4) ? weights.xy : weights.yx;