for (by = -boxsize ; by <= boxsize; by++) {
for (bx = -boxsize ; bx <= boxsize; bx++) {
indx = wrapVal(ix + bx, 0, teximage->width);
for (by = -boxsize ; by <= boxsize; by++) {
for (bx = -boxsize ; bx <= boxsize; bx++) {
indx = wrapVal(ix + bx, 0, teximage->width);