tri tr;
            tr.v[0] = sf[i2];
            tr.v[1] = sf[i1];
            tr.v[2] = sf[i0];
            bool vc[3] = {clipv[i2], clipv[i1], clipv[i0]};
            bool isQuad = false;
            tri extraTri;

            if(vc[0] || vc[1] || vc[2]) {
                if(vc[0] && vc[1] && vc[2])
                    continue;

                isQuad = (!vc[0] && (!vc[1] || !vc[2])) || (!vc[1] && !vc[2]);

                int clipIn = !vc[0] &&  vc[1] ? 0 : (!vc[1] &&  vc[2] ? 1 : 2);
                int clipOt =  vc[0] && !vc[1] ? 0 : ( vc[1] && !vc[2] ? 1 : 2);
                v3 clipVec[2];

                for(int ix=0; ix<2; ix++) {

                    int iva = ix==0 ? (clipIn+1)%3 : clipOt;
                    int ivb = ix==0 ? clipIn : (clipOt+1)%3;

                    float za = tr.v[iva].z;
                    float zb = tr.v[ivb].z;
                    float ip = 0;
                    if(za != zb)
                        ip = (zClip - za) / (zb - za);

                    float zFac = zb / zClip;

                    clipVec[ix].mkClip(tr.v[iva], tr.v[ivb], ip, zFac);
                }

                if(!isQuad)
                    tr.v[(clipIn+1)%3] = clipVec[0], tr.v[clipOt] = clipVec[1];
                else {
                    extraTri = tr;
                    tr.v[(clipIn+1)%3] = clipVec[0];
                    extraTri.v[clipIn] = clipVec[0];
                    extraTri.v[clipOt] = clipVec[1];
                }

            }