int pass;
for(pass=0;pass<2;pass++) {
intbbox_t bbox = intbbox_from_polygon(poly1, zoom);
unsigned char*bitmap1 = render_polygon(poly1, &bbox, zoom, rule, &onepolygon);
int pass;
for(pass=0;pass<2;pass++) {
intbbox_t bbox = intbbox_from_polygon(poly1, zoom);
unsigned char*bitmap1 = render_polygon(poly1, &bbox, zoom, rule, &onepolygon);