%------判斷多邊形是否相交函數--------------------------
function result = poly_cross(poly1x,poly1y,poly2x,poly2y)

result = false;
for i = 1:(length(poly1x)-1)
    x1 = poly1x(i);
    y1 = poly1y(i);
    x2 = poly1x(i+1);
    y2 = poly1y(i+1);
   
    for j = 1:(length(poly2x)-1)
        x3 = poly2x(j);
        y3 = poly2y(j);
        x4 = poly2x(j+1);
        y4 = poly2y(j+1);
        if line_cross(x1,y1,x2,y2,x3,y3,x4,y4)
            result = true;
            return;
        end
    end
end

%ptr00=p1+nP1-1,ptr01=p1,i=0;   i <nP1;   i++,ptr00=ptr01,ptr01++