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>



 //---------------------------------  Edge  ------------------------------//


 class Edge
    {
       public:
      int yUpper;

      float xIntersect;
      float dxPerScan;

      Edge *next;
    };


 //--------------------------  PointCoordinates  -------------------------//


 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;
         }
    };



 //-----------------------  Function Prototypes  -------------------------//



 void show_screen( );

 void Fill_polygon(const int,const int [],const int);

 void insertEdge(Edge *,Edge *);
 void makeEdgeRec(const PointCoordinates,const PointCoordinates,
                         const int,Edge *,Edge *[]);
 void buildEdgeList(const int,const PointCoordinates [],Edge *[]);
 void buildActiveList(const int,Edge *,Edge *[]);
 void fillScan(const int,const Edge *,const int);
 void deleteAfter(Edge []);
 void updateActiveList(const int,Edge []);
 void resortActiveList(Edge []);

 const int yNext(const int,const int,const PointCoordinates []);

 void Polygon(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( );

       int n=10;
       int polygon_points[20]={ 220,340 , 220,220 , 250,170 , 270,200 ,
                300,140 , 320,240 , 320,290 , 420,220 ,
                420,340 , 220,340 };

       setcolor(15);
     Polygon(10,polygon_points);

       Fill_polygon(n,polygon_points,9);

       getch( );
       return 0;
    }


 //----------------------------  Fill_polygon( )  ------------------------//


 void Fill_polygon(const int n,const int ppts[],const int fill_color)
    {
       Edge *edges[480];
       Edge *active;

       PointCoordinates *pts=new PointCoordinates[n];

       for(int count_1=0;count_1<n;count_1++)
      {
         pts[count_1].x=(ppts[(count_1*2)]);
         pts[count_1].y=(ppts[((count_1*2)+1)]);
      }

       for(int count_2=0;count_2<640;count_2++)
      {
         edges[count_2]=new Edge;
         edges[count_2]->next=NULL;
      }

       buildEdgeList(n,pts,edges);

       active=new Edge;
       active->next=NULL;

       for(int count_3=0;count_3<480;count_3++)
      {
         buildActiveList(count_3,active,edges);

         if(active->next)
        {
           fillScan(count_3,active,fill_color);
           updateActiveList(count_3,active);
           resortActiveList(active);
        }
      }

       Polygon(n,ppts);

       delete pts;
    }


 //-------------------------------  yNext( )  ----------------------------//


 const int yNext(const int k,const int cnt,const PointCoordinates pts[])
    {
       int j;

       if((k+1)>(cnt-1))
      j=0;

       else
      j=(k+1);

       while(pts[k].y==pts[j].y)
      {
         if((j+1)>(cnt-1))
        j=0;

         else
        j++;
      }

       return (pts[j].y);
    }


 //-----------------------------  insertEdge( )  -------------------------//


 void insertEdge(Edge *list,Edge *edge)
    {
       Edge *p;
       Edge *q=list;

       p=q->next;

       while(p!=NULL)
      {
         if(edge->xIntersect<p->xIntersect)
        p=NULL;

         else
        {
           q=p;
           p=p->next;
        }
      }

       edge->next=q->next;
       q->next=edge;
    }


 //---------------------------  makeEdgeRec( )  --------------------------//


 void makeEdgeRec(const PointCoordinates lower,const PointCoordinates upper,
                   const int yComp,Edge *edge,Edge *edges[])
    {
       edge->dxPerScan=((upper.x-lower.x)/(upper.y-lower.y));
       edge->xIntersect=lower.x;

       if(upper.y<yComp)
      edge->yUpper=(upper.y-1);

       else
      edge->yUpper=upper.y;

       insertEdge(edges[lower.y],edge);
    }


 //---------------------------  buildEdgeList( )  ------------------------//


 void buildEdgeList(const int cnt,const PointCoordinates pts[],Edge *edges[])
    {
       Edge *edge;
       PointCoordinates v1;
       PointCoordinates v2;

       int yPrev=(pts[cnt-2].y);

       v1.x=pts[cnt-1].x;
       v1.y=pts[cnt-1].y;

       for(int count=0;count<cnt;count++)
      {
         v2=pts[count];

         if(v1.y!=v2.y)
        {
           edge=new Edge;

           if(v1.y<v2.y)
              makeEdgeRec(v1,v2,yNext(count,cnt,pts),edge,edges);

           else
              makeEdgeRec(v2,v1,yPrev,edge,edges);
        }

         yPrev=v1.y;
         v1=v2;
      }
    }


 //------------------------  buildActiveList( )  -------------------------//


 void buildActiveList(const int scan,Edge *active,Edge *edges[])
   {
    Edge *p;
    Edge *q;

    p=edges[scan]->next;

    while(p)
      {
         q=p->next;

         insertEdge(active,p);

         p=q;
      }
    }


 //----------------------------  fillScan( )  ----------------------------//


 void fillScan(const int scan,const Edge *active,const int fill_color)
    {
       Edge *p1;
       Edge *p2;

       p1=active->next;

       while(p1)
      {
         p2=p1->next;

         for(int count=p1->xIntersect;count<=p2->xIntersect;count++)
        putpixel(count,scan,fill_color);

         p1=p2->next;
      }
    }


 //-------------------------  deleteAfter( )  ----------------------------//


 void deleteAfter(Edge * q)
    {
       Edge *p=q->next;

       q->next=p->next;

       delete p;
    }


 //-------------------------  updateActiveList( )  -----------------------//


 void updateActiveList(const int scan,Edge *active)
    {
       Edge *q=active;
       Edge *p=active->next;

       while(p)
      {
         if(scan>=p->yUpper)
        {
           p=p->next;

           deleteAfter(q);
        }

         else
        {
           p->xIntersect=(p->xIntersect+p->dxPerScan);
           q=p;
           p=p->next;
        }
      }
    }


 //-------------------------  resortActiveList( )  -----------------------//


 void resortActiveList(Edge *active)
    {
       Edge *q;
       Edge *p=active->next;

       active->next=NULL;

       while(p)
      {
         q=p->next;

        insertEdge(active,p);

         p=q;
      }
    }


 //-----------------------------  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(178,26,450,38);

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

     setcolor(11);
       outtextxy(185,29,\"Scan Line Polygon Fill 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(229,450,\"Press any Key to exit.\");
    }

 
 
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