C++ Programming Tutorial

 
 
 

Graphics Programming

Quadratic Surfaces

Draw a Sphere using Ellipses Draw a Sphere using Parametric Equations Draw an Ellipsoid using Parametric Equations

Character Generation

Urdu Alphabets using Stroke Method Urdu Alphabets using Matrix Method

Arc

Circular Arc using Trigo. Method Elliptical Arc using Trigo. Method

General Programs

C-Curve of nth order K-Curve of nth order Cubic Bezier Curve Bezier Curve of nth degree Scanfill algorithm Boundary Fill - 8 Connected Point Flood fill algorithm Rotate About Origin Rotate about reference point Scaling about origin Scaling about reference point Polyline translation Reflection in x axis Reflection in y Axis Reflection on any line Midpoint Circle Drawing Bresenhams Line Algorithm (BLA) Generate a pattern Draw a Chess Board Draw a Luddo Board Deterministic Finite Automation for identifier Kurskals algo - Minimum Cost Spanning Tree

Windows Programs

Checkbox like windows Simple windows & buttons Moving message box like windows Text box Graphical Rep. of tower of hanoi Graphical menu - operate it using arrow keys Text animation

Line

Line using Parametric equations Line-Cartesian Slope-Intercept Equation simple imp Line using Cartesian Slope-Intercept Equation Line - BLA - slopes negative and greater than 1 Line - BLA - slopes negative and less than 1 Line - BLA - slopes positive and greater than 1 Line - BLA - slopes positive and less than 1 DDA line drawing algorithm Bresenham line drawing algorithm Cohen sutherland Line clipping algo.

Line Styles

Different kinds of Dashed Lines Different kinds of Thick Lines

Polygons

Draw a Polygon Draw a Triangle Draw a Rectangle Sutherland-Hodgeman Polygon Clipping Algo

Circle

Circle using Trigo. Method Circle using Polynomial Method Circle using Bresenhams Circle algo. Circle using MidPoint Circle algo.

Ellipse

Ellipse using Polynomial Method Ellipse using Trigo. Method Ellipse using MidPoint Ellipse algo.

2D Transformations

Translation Transformation Scaling Transformation Scaling Trans along a Fixed Point Scaling Trans along Arbitrary Direction Rotation Transformation Rotation Trans along a Pivot Point Reflection tran of x-axix, y-axis and w.r.t origin Reflection tran of line y=x and y=-x X-Direction Shear Transformation Y-Direction Shear Transformation

2D Viewing - Clipping

Window-to-Viewport Coordinate Tran Point Clipping Algorithm Cohen-Sutherland Line Clipping Algo Cohen-Sutherland MidPoint Subdivision Line Nicol Lee Nicol algo. for Line Clipping Liang-Barsky Line Clipping Algo Window-to-Viewport Transformaton None-or-All String Clipping Strategy None-or-All Character Clipping Strategy

3D Object Representations

3D object using Polygon-Mesh Rep. 3D object - Translational Sweep Representatiom 3D object - Rotational Sweep Rep.

3D Transformations

3D Rotation Trans along x-axis 3D Rotation Trans along y-axis 3D Rotation Trans along z-axis 3D Reflection Trans along xy-plane 3D Reflection Trans along yz-plane 3D Reflection Trans along zx-plane 3D Shearing Trans along x-axis 3D Shearing Trans along y-axis 3D Shearing Trans along z-axis

Bezier Curves - Surfaces

3D Cubic Bezier Curve 3D Bezier Curve of nth degree 3D Piece-Wise Bezier Curve of nth degree 3D Bezier Surface for MxN control points

Projection

3D objects - Standard Perspective Projection 3D obj - Arbitrary Plane and Center of Projection 3D objects using General Perspective Projection 3D obj-Orthographics Proje Parallel onto xy-plane 3D obj-Cavalier Oblique Parallel prj-xy-plane 3D obj-Cabinet Oblique Parallel prj - xy-plane

Fill Algorithm or Area Filling

Geometric shapes using Boundary Geometric shapes - Boundary - Linked List Geometric shapes using Flood Geometric shapes - Flood - Linked-List Polygon using Scan Line Polygon Rectangle using Scan-Line Rectangle Circle using Scan-Line Circle Circle - Scan-Line Circle - Polar Coordinates
 
 
 # include <iostream.h>
 # include <graphics.h>
 # include    <conio.h>
 # include     <math.h>


 class PointCoordinates
    {
       public:
      float x;
      float y;

      PointCoordinates( )
         {
        x=0;
        y=0;
         }
    };


 //---------------------------  LineCoordinates  -------------------------//


 class LineCoordinates
    {
       public:
      float x_1;
      float y_1;
      float x_2;
      float y_2;

      LineCoordinates( )
         {
        x_1=0;
        y_1=0;
        x_2=0;
        y_2=0;
         }

      LineCoordinates(const float x1,const float y1,
                          const float x2,const float y2)
         {
        x_1=x1;
        y_1=y1;
        x_2=x2;
        y_2=y2;
         }
    };


 //-------------------------  WindowCoordinates  -------------------------//


 class WindowCoordinates
    {
       public:
      float x_min;
      float y_min;
      float x_max;
      float y_max;

      WindowCoordinates(const float x1,const float y1,
                          const float x2,const float y2)
         {
        x_min=x1;
        y_min=y1;
        x_max=x2;
        y_max=y2;
         }
    };


 void show_screen( );

 void clip_polygon(const WindowCoordinates,const int,const int []);

 const int check_line(const LineCoordinates,const LineCoordinates);
 const int check_point(const LineCoordinates,const float,const float);

 const PointCoordinates get_intersection_point(LineCoordinates,
                                LineCoordinates);

 void Polygon(const int,const int []);
 void Rectangle(const int,const int,const int,const int);
 void Line(const int,const int,const int,const int);


 int main( )
    {
       int driver=VGA;
       int mode=VGAHI;

       initgraph(&driver,&mode,\"..\\\\Bgi\");

       show_screen( );

       WindowCoordinates WC(180,140,470,340);

       setcolor(15);
     Rectangle(WC.x_min,WC.y_min,WC.x_max,WC.y_max);

       int n=10;

       int polygon_vertices[20]={ 100,240 , 180,370 , 210,310 , 380,375 ,
                  520,310 , 480,260 , 510,80  , 280,180 ,
                  210,90  , 100,240 };

       setcolor(7);
     Polygon(n,polygon_vertices);

       setcolor(15);
       settextstyle(0,0,1);
     outtextxy(300,240,\"Window\");
     outtextxy(80,240,\"Polygon\");

       char Key=NULL;

       do
      {
         Key=getch( );
      }
       while(Key!=\'C\' && Key!=\'c\');

       settextstyle(0,0,1);
     setcolor(0);
       outtextxy(163,450,\"  Press \'C\' to see the Clipped Polygon. \");

    setcolor(15);
       outtextxy(163,450,\"------                          ---------\");

     setcolor(12);
       outtextxy(213,450,\"  Press any Key to exit.  \");

       clip_polygon(WC,n,polygon_vertices);

       setcolor(15);
       settextstyle(0,0,1);
     outtextxy(280,155,\"Clipped Polygon\");

       getch( );
       return 0;
    }



 //--------------------------  clip_polygon( )  --------------------------//


 void clip_polygon(const WindowCoordinates wc,const int n,
                         const int polygon_edges[])
    {
       int edges_counter;
       int number_of_edges=n;

       int *edges=new int[(n*4)];
       int *clipped_edges=new int[(n*4)];

       for(int count_1=0;count_1<(n*2);count_1++)
      edges[count_1]=polygon_edges[count_1];

       LineCoordinates window_line;

       for(int count_2=1;count_2<=4;count_2++)
      {
         edges_counter=1;

         for(int count_3=0;count_3<(number_of_edges*4);count_3++)
        clipped_edges[count_3]=0;

         if(count_2==1)
        {
           window_line.x_1=wc.x_min;
           window_line.y_1=wc.y_max;
           window_line.x_2=wc.x_max;
           window_line.y_2=wc.y_max;
        }

         else if(count_2==2)
        {
           window_line.x_1=wc.x_max;
           window_line.y_1=wc.y_max;
           window_line.x_2=wc.x_max;
           window_line.y_2=wc.y_min;
        }

         else if(count_2==3)
        {
           window_line.x_1=wc.x_max;
           window_line.y_1=wc.y_min;
           window_line.x_2=wc.x_min;
           window_line.y_2=wc.y_min;
        }

         else if(count_2==4)
        {
           window_line.x_1=wc.x_min;
           window_line.y_1=wc.y_min;
           window_line.x_2=wc.x_min;
           window_line.y_2=wc.y_max;
        }

         int rule_no;

         PointCoordinates point;

         for(int count_4=1;count_4<number_of_edges;count_4++)
        {
           LineCoordinates line(edges[((count_4*2)-2)],
                    edges[((count_4*2)-1)],
                    edges[(count_4*2)],
                    edges[((count_4*2)+1)]);

           rule_no=check_line(window_line,line);

           switch(rule_no)
              {
             case 1 : clipped_edges[(edges_counter*2)]=
                             (int)(line.x_2+0.5);
                  clipped_edges[((edges_counter*2)+1)]=
                             (int)(line.y_2+0.5);
                  edges_counter++;
                  break;

             case 2 : break;

             case 3 : point=
                    get_intersection_point(window_line,line);

                  clipped_edges[(edges_counter*2)]=
                              (int)(point.x+0.5);
                  clipped_edges[((edges_counter*2)+1)]=
                              (int)(point.y+0.5);
                  edges_counter++;
                  break;

             case 4 : point=
                    get_intersection_point(window_line,line);

                  clipped_edges[(edges_counter*2)]=
                              (int)(point.x+0.5);
                  clipped_edges[((edges_counter*2)+1)]=
                              (int)(point.y+0.5);
                  edges_counter++;

                  clipped_edges[(edges_counter*2)]=
                             (int)(line.x_2+0.5);
                  clipped_edges[((edges_counter*2)+1)]=
                             (int)(line.y_2+0.5);
                  edges_counter++;
                  break;
              }
        }

         clipped_edges[0]=clipped_edges[((edges_counter*2)-2)];
         clipped_edges[1]=clipped_edges[((edges_counter*2)-1)];

         for(int count_5=0;count_5<(edges_counter*2);count_5++)
        edges[count_5]=0;

         number_of_edges=edges_counter;

         for(int count_6=0;count_6<(edges_counter*2);count_6++)
        edges[count_6]=clipped_edges[count_6];
     }

       setcolor(10);
     Polygon(number_of_edges,edges);

       delete edges;
       delete clipped_edges;
    }


 //----------------------------  check_line( )  --------------------------//


 const int check_line(const LineCoordinates line,const LineCoordinates edge)
    {
       int rule_number=0;
       int point_1=check_point(line,edge.x_1,edge.y_1);
       int point_2=check_point(line,edge.x_2,edge.y_2);

       if(point_1==1 && point_2==1)
      rule_number=1;

       else if(point_1!=1 && point_2!=1)
      rule_number=2;

       else if(point_1==1 && point_2!=1)
      rule_number=3;

       else if(point_1!=1 && point_2==1)
      rule_number=4;

       return rule_number;
    }


 //----------------------------  check_point( )  -------------------------//


 const int check_point(const LineCoordinates lc,const float x,const float y)
    {
       float c=(((lc.x_2-lc.x_1)*(y-lc.y_1))-((lc.y_2-lc.y_1)*(x-lc.x_1)));

       if(c<=0)
      return 1;

       else
      return 0;
    }


 //----------------------  get_intersection_point( )  --------------------//


 const PointCoordinates get_intersection_point(LineCoordinates lc1,
                            LineCoordinates lc2)
    {
       float x_min=lc1.x_1;
       float x_max=lc1.x_2;
       float y_min=lc1.y_1;
       float y_max=lc1.y_2;

       if(lc1.x_1==lc1.x_2)
      {
         if(lc2.y_2>=lc2.y_1 && lc2.y_2>y_max)
        y_max=lc2.y_2;

         else if(lc2.y_1>lc2.y_2 && lc2.y_1>y_max)
        y_max=lc2.y_1;

         if(lc2.y_1<=lc2.y_2 && lc2.y_1<y_min)
        y_min=lc2.y_1;

         else if(lc2.y_2<lc2.y_1 && lc2.y_2<y_min)
        y_min=lc2.y_2;
      }

       else if(lc1.y_1==lc1.y_2)
      {
         if(lc2.x_2>=lc2.x_1 && lc2.x_2>x_max)
        x_max=lc2.x_2;

         else if(lc2.x_2<lc2.x_1 && lc2.x_1>x_max)
        x_max=lc2.x_1;

         if(lc2.x_1<=lc2.x_2 && lc2.x_1<x_min)
        x_min=lc2.x_1;

         else if(lc2.x_2<lc2.x_1 && lc2.x_2<x_min)
        x_min=lc2.x_2;
      }

       float x_mid;
       float y_mid;

       if(lc2.y_1>y_max)
      {
         while(lc2.y_1!=y_max)
        {
           x_mid=((lc2.x_1+lc2.x_2)/2);
           y_mid=((lc2.y_1+lc2.y_2)/2);

           if(y_mid>=y_max)
              {
             lc2.x_1=x_mid;
             lc2.y_1=y_mid;
              }

           else
              {
             lc2.x_2=x_mid;
             lc2.y_2=y_mid;
              }
        }
      }

       else if(lc2.y_1<y_min)
      {
         while(lc2.y_1!=y_min)
        {
           x_mid=((lc2.x_1+lc2.x_2)/2);
           y_mid=((lc2.y_1+lc2.y_2)/2);

           if(y_mid<=y_min)
              {
             lc2.x_1=x_mid;
             lc2.y_1=y_mid;
              }

           else
              {
             lc2.x_2=x_mid;
             lc2.y_2=y_mid;
              }
        }
      }

       if(lc2.x_1>x_max)
      {
         while(lc2.x_1!=x_max)
        {
           x_mid=((lc2.x_1+lc2.x_2)/2);
           y_mid=((lc2.y_1+lc2.y_2)/2);

           if(x_mid>=x_max)
              {
             lc2.x_1=x_mid;
             lc2.y_1=y_mid;
              }

           else
              {
             lc2.x_2=x_mid;
             lc2.y_2=y_mid;
              }
        }
      }

       else if(lc2.x_1<x_min)
      {
         while(lc2.x_1!=x_min)
        {
           x_mid=((lc2.x_1+lc2.x_2)/2);
           y_mid=((lc2.y_1+lc2.y_2)/2);

           if(x_mid<=x_min)
              {
             lc2.x_1=x_mid;
             lc2.y_1=y_mid;
              }

           else
              {
             lc2.x_2=x_mid;
             lc2.y_2=y_mid;
              }
        }
      }

       PointCoordinates ipt;

       ipt.x=lc2.x_1;
       ipt.y=lc2.y_1;

       return ipt;
    }



 //---------------------------  Rectangle( )  ----------------------------//


 void Rectangle(const int x_1,const int y_1,const int x_2,const int y_2)
    {
       Line(x_1,y_1,x_2,y_1);
       Line(x_2,y_1,x_2,y_2);
       Line(x_2,y_2,x_1,y_2);
       Line(x_1,y_2,x_1,y_1);
    }


 //-----------------------------  Polygon( )  ----------------------------//


 void Polygon(const int n,const int coordinates[])
    {
       if(n>=2)
      {
         Line(coordinates[0],coordinates[1],
                         coordinates[2],coordinates[3]);

         for(int count=1;count<(n-1);count++)
        Line(coordinates[(count*2)],coordinates[((count*2)+1)],
                        coordinates[((count+1)*2)],
                        coordinates[(((count+1)*2)+1)]);
      }
    }


 //--------------------------  Line( )  ------------------------//


 void Line(const int x_1,const int y_1,const int x_2,const int y_2)
    {
       int color=getcolor( );

       int x1=x_1;
       int y1=y_1;

       int x2=x_2;
       int y2=y_2;

       if(x_1>x_2)
      {
         x1=x_2;
         y1=y_2;

         x2=x_1;
         y2=y_1;
      }

       int dx=abs(x2-x1);
       int dy=abs(y2-y1);
       int inc_dec=((y2>=y1)?1:-1);

       if(dx>dy)
      {
         int two_dy=(2*dy);
         int two_dy_dx=(2*(dy-dx));
         int p=((2*dy)-dx);

         int x=x1;
         int y=y1;

         putpixel(x,y,color);

         while(x<x2)
        {
           x++;

           if(p<0)
              p+=two_dy;

           else
              {
             y+=inc_dec;
             p+=two_dy_dx;
              }

           putpixel(x,y,color);
        }
      }

       else
      {
         int two_dx=(2*dx);
         int two_dx_dy=(2*(dx-dy));
         int p=((2*dx)-dy);

         int x=x1;
         int y=y1;

         putpixel(x,y,color);

         while(y!=y2)
        {
           y+=inc_dec;

           if(p<0)
              p+=two_dx;

           else
              {
             x++;
             p+=two_dx_dy;
              }

           putpixel(x,y,color);
        }
      }
    }


 //--------------------------  show_screen( )  ---------------------------//


 void show_screen( )
    {
       setfillstyle(1,1);
     bar(125,26,510,38);

       settextstyle(0,0,1);
     setcolor(15);
       outtextxy(5,5,\"******************************************************************************\");
       outtextxy(5,17,\"*-**************************************************************************-*\");
       outtextxy(5,29,\"*-------------                                                  -------------*\");
       outtextxy(5,41,\"*-**************************************************************************-*\");
       outtextxy(5,53,\"*-**************************************************************************-*\");

     setcolor(11);
       outtextxy(134,29,\"Sutherland-Hodgeman Polygon Clipping Algorithm\");

     setcolor(15);

       for(int count=0;count<=30;count++)
          outtextxy(5,(65+(count*12)),\"*-*                                                                        *-*\");

       outtextxy(5,438,\"*-**************************************************************************-*\");
       outtextxy(5,450,\"*-------------------                                         ----------------*\");
       outtextxy(5,462,\"******************************************************************************\");

     setcolor(12);
       outtextxy(163,450,\"  Press \'C\' to see the Clipped Polygon. \");
    }