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#include <iostream>
#include <cmath>
#include <fstream>
using namespace std;
const int LARGE_NUM=1.0E10;
struct Point
{
public:
double x,y;
};
struct Line_seg
{
public:
Point endpt1, endpt2;
double slope, intercept;
};
class Boundary_map
{
private:
enum {NUM_MAP_PTS=10};
Point boundary_pts[NUM_MAP_PTS+1];
public:
Boundary_map();
void read_boundary_pts();
void map_wrap_around();
Point* get_boundary_pts();
int get_num_boundary_pts();
};
class Probe
{
private:
Point sample_pt, endpt1, endpt2;
int num_crosses;
Point probe_line_intersect (Line_seg);
int probe_line_seg_intersect (Point, Line_seg);
public:
Probe();
void read_sample_pt();
void check_map_boundary (Point*, int);
};
Boundary_map::Boundary_map()
{
int i;
for(i=0; i <NUM_MAP_PTS+1; i++)
{
boundary_pts[i].x=0;
boundary_pts[i].y=0;
}
}
void Boundary_map::read_boundary_pts()
{
int i;
ifstream infile ("C:\\BNDARY.DAT");
for(i=0; i<NUM_MAP_PTS; i++)
{
infile>>boundary_pts[i].x;
infile>>boundary_pts[i].y;
}
}
void Boundary_map::map_wrap_around()
{
boundary_pts[NUM_MAP_PTS]=boundary_pts[0];
}
Point* Boundary_map::get_boundary_pts();
{
return (boundary_pts);
}
int Boundary_map:: get_num_boundary_pts()
{
return (NUM_MAP_PTS+1);
}
Probe::Probe()
{
sample_pt.x=0;
sample_pt.y=0;
endpt1.x=0;
endpt1.y=0;
endpt2.x=LARGE_NUM;
endpt2.y=0;
num_crosses=0;
}
void Probe::read_sample_pt()
{
cout<<"Enter the x and y coordinates of the sample point"<<endl;
cin>>sample_pt.x>>sample_pt.y;
endpt1=sample_pt;
endpt2.y=sample_pt.y;
}
Point Probe::probe_line_intersect (Line_seg map_line_seg)
{
Point intersect_pt;
double probe_slope, probe_intercept;
if(fabs(map_line_seg.endpt2.x-map_line_seg.endpt1.x)<1.0E-20)
{
intersect_pt.x=map_line_seg.endpt1.x;
intersect_pt.y=endpt1.y;
}
else
{
map_line_seg.slope=(map_line_seg.slope=(map_line_seg.endpt2.y
-map_line_seg.endpt1.y)/(map_line_seg.endpt2.x
-map_line_seg.endpt1.x);
map_line_seg.intercept=map_line_seg.endpt2.y
-map_line_seg.slope*map_line_seg.endpt2.x;
probe_slope=0.0;
probe_intercept=sample_pt.y;
if(fabs(map_line_seg.slope)<1.0E-20)
{
intersect_pt.x=LARGE_NUM;
intersect_pt.y=LARGE_NUM;
}
intersect_pt.x=(probe_intercept-map_line_seg.intercept)/(map_line_seg.slope-probe_slope);
intersect_pt.y=map_line_seg.slope*intersect_pt.x+map_line_seg.intercept;
}
return (intersect_pt);
}
int Probe::probe_line_seg_intersect(Point intersect_pt, Line_seg seg2)
{
Line_seg seg1;
double x_low_1, x_high_1, x_low_2, x_high_2;
double y_low_1, y_high_1, y_low_2, y_high_2;
seg1.endpt1=endpt1;
seg1.endpt2=endpt2;
x_low_1=(seg1.endpt1.x<seg1.endpt2.x)?
seg1.endpt1.x:seg1.endpt2.x;
x_high_1=(seg1.endpt1.x>seg1.endpt2.x)?
seg1.endpt1.x:seg1.endpt2.x;
x_low_2=(seg2.endpt1.x<seg2.endpt2.x)?
seg2.endpt1.x:seg2.endpt2.x;
x_high_2=(seg2.endpt1.x>seg2.endpt2.x)?
seg2.endpt1.x:seg2.endpt2.x;
y_low_1=(seg1.endpt1.y<seg1.endpt2.y)?
seg1.endpt1.y:seg1.endpt2.y;
y_high_1=(seg1.endpt1.y>seg1.endpt2.y)?
seg1.endpt1.y:seg1.endpt2.y;
y_low_2=(seg2.endpt1.y<seg2.endpt2.y)?
seg2.endpt1.y:seg2.endpt2.y;
y_high_2=(seg2.endpt1.y>seg2.endpt2.y)?
seg2.endpt1.y:seg2.endpt2.y;
if((x_low_1<=intersect_pt.x && intersect_pt.x<=x_high_1) && (x_low_2<=intersect_pt.x &&
intersect_pt.x<=x_high_2) && (y_low_1<= intersect_pt.y && intersect_pt.y<=y_high_1) &&
(y_low_2<=intersect_pt.y && intersect_pt.y<=y_high_2))
{
return(1);
}
else
{
return(0);
}
}
void Probe:: check_map_boundary(Point* bnd_pt, int num_pts)
{
int i, does_cross, even_odd;
Point intersect_pt;
Line_seg map_line_seg;
for(i=0;i<num_pts-1;i++)
{
map_line_seg.endpt1=bnd_pt[i];
map_line_seg.endpt2=bnd_pt[i+1];
intersect_pt=probe_line_intersect(map_line_seg);
does_cross=probe_line_seg_intersect(intersect_pt, map_line_seg);
num_crosses+=does_cross;
}
even_odd=num_crosses % 2;
if(even_odd==0) cout << "The sample point is outside the " "plume. " <<endl;
if(even_odd==1) cout << "The sample point is inside the " "plume. " <<endl;
}
int main ()
{
Boundary_map plume_map;
Probe probe_from_water_sample;
plume_map.read_boundary_pts();
plume_map.map_wrap_around();
probe_from_water_sample.read_sample_pt();
probe_from_water_sample.check_map_boundary
(plume_map.get_boundary_pts(),
plume_map.get_num_boundary_pts());
}
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