                  a += i > 7 ? min(12., D) : D;
                    pa = length(p2);
                }
            a *= a * a;
            float s1 = s + zoffset;
            float fade = pow(0.560, max(0., float(r) - sampleShift));
            v += fade;
            if(r == 0)
                {
                    fade *= (1. - (sampleShift));
                }
            if(r == 8 - 1)
                {
                    fade *= sampleShift;
                }
            v += vec3(s1, s1 * s1, s1 * s1 