+ } else {
+ for (i = 0; i < 4; ++i) {
+ xx[i][0] = patch->x[i][0];
+ yy[i][0] = patch->y[i][0];
+ xx[i][1] = 0.5 * (patch->x[i][0] + patch->x[i][1]);
+ yy[i][1] = 0.5 * (patch->y[i][0] + patch->y[i][1]);
+ xxm = 0.5 * (patch->x[i][1] + patch->x[i][2]);
+ yym = 0.5 * (patch->y[i][1] + patch->y[i][2]);
+ xx[i][6] = 0.5 * (patch->x[i][2] + patch->x[i][3]);
+ yy[i][6] = 0.5 * (patch->y[i][2] + patch->y[i][3]);
+ xx[i][2] = 0.5 * (xx[i][1] + xxm);
+ yy[i][2] = 0.5 * (yy[i][1] + yym);
+ xx[i][5] = 0.5 * (xxm + xx[i][6]);
+ yy[i][5] = 0.5 * (yym + yy[i][6]);
+ xx[i][3] = xx[i][4] = 0.5 * (xx[i][2] + xx[i][5]);
+ yy[i][3] = yy[i][4] = 0.5 * (yy[i][2] + yy[i][5]);
+ xx[i][7] = patch->x[i][3];
+ yy[i][7] = patch->y[i][3];
+ }
+ for (i = 0; i < 4; ++i) {
+ patch00.x[0][i] = xx[0][i];
+ patch00.y[0][i] = yy[0][i];
+ patch00.x[1][i] = 0.5 * (xx[0][i] + xx[1][i]);
+ patch00.y[1][i] = 0.5 * (yy[0][i] + yy[1][i]);
+ xxm = 0.5 * (xx[1][i] + xx[2][i]);
+ yym = 0.5 * (yy[1][i] + yy[2][i]);
+ patch10.x[2][i] = 0.5 * (xx[2][i] + xx[3][i]);
+ patch10.y[2][i] = 0.5 * (yy[2][i] + yy[3][i]);
+ patch00.x[2][i] = 0.5 * (patch00.x[1][i] + xxm);
+ patch00.y[2][i] = 0.5 * (patch00.y[1][i] + yym);
+ patch10.x[1][i] = 0.5 * (xxm + patch10.x[2][i]);
+ patch10.y[1][i] = 0.5 * (yym + patch10.y[2][i]);
+ patch00.x[3][i] = 0.5 * (patch00.x[2][i] + patch10.x[1][i]);
+ patch00.y[3][i] = 0.5 * (patch00.y[2][i] + patch10.y[1][i]);
+ patch10.x[0][i] = patch00.x[3][i];
+ patch10.y[0][i] = patch00.y[3][i];
+ patch10.x[3][i] = xx[3][i];
+ patch10.y[3][i] = yy[3][i];
+ }
+ for (i = 4; i < 8; ++i) {
+ patch01.x[0][i-4] = xx[0][i];
+ patch01.y[0][i-4] = yy[0][i];
+ patch01.x[1][i-4] = 0.5 * (xx[0][i] + xx[1][i]);
+ patch01.y[1][i-4] = 0.5 * (yy[0][i] + yy[1][i]);
+ xxm = 0.5 * (xx[1][i] + xx[2][i]);
+ yym = 0.5 * (yy[1][i] + yy[2][i]);
+ patch11.x[2][i-4] = 0.5 * (xx[2][i] + xx[3][i]);
+ patch11.y[2][i-4] = 0.5 * (yy[2][i] + yy[3][i]);
+ patch01.x[2][i-4] = 0.5 * (patch01.x[1][i-4] + xxm);
+ patch01.y[2][i-4] = 0.5 * (patch01.y[1][i-4] + yym);
+ patch11.x[1][i-4] = 0.5 * (xxm + patch11.x[2][i-4]);
+ patch11.y[1][i-4] = 0.5 * (yym + patch11.y[2][i-4]);
+ patch01.x[3][i-4] = 0.5 * (patch01.x[2][i-4] + patch11.x[1][i-4]);
+ patch01.y[3][i-4] = 0.5 * (patch01.y[2][i-4] + patch11.y[1][i-4]);
+ patch11.x[0][i-4] = patch01.x[3][i-4];
+ patch11.y[0][i-4] = patch01.y[3][i-4];
+ patch11.x[3][i-4] = xx[3][i];
+ patch11.y[3][i-4] = yy[3][i];
+ }
+ //~ if the shading has a Function, this should interpolate on the
+ //~ function parameter, not on the color components
+ for (i = 0; i < nComps; ++i) {
+ patch00.color[0][0].c[i] = patch->color[0][0].c[i];
+ patch00.color[0][1].c[i] = (patch->color[0][0].c[i] +
+ patch->color[0][1].c[i]) / 2;
+ patch01.color[0][0].c[i] = patch00.color[0][1].c[i];
+ patch01.color[0][1].c[i] = patch->color[0][1].c[i];
+ patch01.color[1][1].c[i] = (patch->color[0][1].c[i] +
+ patch->color[1][1].c[i]) / 2;
+ patch11.color[0][1].c[i] = patch01.color[1][1].c[i];
+ patch11.color[1][1].c[i] = patch->color[1][1].c[i];
+ patch11.color[1][0].c[i] = (patch->color[1][1].c[i] +
+ patch->color[1][0].c[i]) / 2;
+ patch10.color[1][1].c[i] = patch11.color[1][0].c[i];
+ patch10.color[1][0].c[i] = patch->color[1][0].c[i];
+ patch10.color[0][0].c[i] = (patch->color[1][0].c[i] +
+ patch->color[0][0].c[i]) / 2;
+ patch00.color[1][0].c[i] = patch10.color[0][0].c[i];
+ patch00.color[1][1].c[i] = (patch00.color[1][0].c[i] +
+ patch01.color[1][1].c[i]) / 2;
+ patch01.color[1][0].c[i] = patch00.color[1][1].c[i];
+ patch11.color[0][0].c[i] = patch00.color[1][1].c[i];
+ patch10.color[0][1].c[i] = patch00.color[1][1].c[i];
+ }
+ fillPatch(&patch00, nComps, depth + 1);
+ fillPatch(&patch10, nComps, depth + 1);
+ fillPatch(&patch01, nComps, depth + 1);
+ fillPatch(&patch11, nComps, depth + 1);