void addEdgeMask(int contourIndex, int edgeMask4, int insideMask) {
			/*
			 * binary abcd abcd vvvv where abcd is edge intersection mask and vvvv is the inside/outside mask (0-15) the
			 * duplication is so that this can be used efficiently either as
			 */
			if (insideMask != 0)
				contourBits |= (1 << contourIndex);
			edgeMask12[contourIndex] = (((edgeMask4 << 4) + edgeMask4) << 4) + insideMask;
			edgeMask12All |= edgeMask12[contourIndex];
			if (insideMask == 0)
				++nOutside;
			else if (insideMask == 0xF)
				++nInside;
			else ++nThrough;
		}