code: @Pure
  	private static boolean intersectsCoplanarTriangle(
  			int i0, int i1, int con, double[] s1, double[] s2, double[] u1, double[] u2, double[] u3) {
  		double Ax,Ay;
  
  		Ax = s2[i0] - s1[i0];
  		Ay = s2[i1] - s1[i1];
  
  		// test edge U0,U1 against V0,V1
  		if (intersectEdgeEdge(i0, i1, con, Ax, Ay, s1, u1, u2)) return true;
  		// test edge U1,U2 against V0,V1
  		if (intersectEdgeEdge(i0, i1, con, Ax, Ay, s1, u2, u3)) return true;
  		// test edge U2,U1 against V0,V1
  		if (intersectEdgeEdge(i0, i1, con, Ax, Ay, s1, u3, u1)) return true;
  
  		return false;
  	}
docs: Replies if coplanar segment-triangle intersect.