Graphics Lab File - After Mid Sem

After Midsemester Examinati ons 1

Table of Contents

After ........................................................................................................................... 1 Mid-semester Examinations........................................................................................1 Table of Contents....................................................................................................... 2 Program 1: Three-Dimensional Transformations........................................................3 Program 2: Point Clipping Algorithm...........................................................................8 Program 3: Cohen Sutherland Line Clipping Algorithm...............................................9 Program 4: Liang Barsky Line Clipping Algorithm.....................................................11 Program 5: Sutherland Hodgeman Polygon Clipping Algorithm................................13 Program 6: Perspective Projections..........................................................................17 Program 7: Parallel Projections.................................................................................19

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Program 1: Three-Dimensional Transformations /********************************************************************* Name: Atishay Jain Subject: Computer Graphics Roll No: 10783017 Program: 3D-Transformations *********************************************************************/ #include<stdio.h> #include #include #include<math.h> #include<stdlib.h> int xp[2],yp[2],z; void display(); void translate(); void scaling(); void rotation(); void matrixmul(int [4][4]); void main() { int gd=DETECT,gm; int ch,i; initgraph(&gd,&gm,"c:\\tc\\bgi"); for(i=0;i<2;i++) { printf("\nEnter X-coordinate of vertex %d : ",i+1); scanf("%d",&xp[i]); printf("\nEnter Y-coordinate of vertex %d : ",i+1); scanf("%d",&yp[i]); } printf("\nEnter The Z-axis For 3d Figure : "); scanf("%d",&z); clrscr(); cleardevice(); display(xp,yp); getche(); do { printf("----- MENU -----"); printf("\n1.TRANSLATION."); printf("\t2.SCALING."); printf("\n3.ROTATION."); printf("\t4.EXIT."); printf("\nEnter Your Choice : "); scanf("%d",&ch); 3

clrscr(); cleardevice(); display(xp,yp); switch(ch) { case 1 : translate(); break; case 2 : scaling(); break; case 3 : rotation(); break; case 4 : exit(0); default: outtextxy(1,66,"-PLEASE SELECT THE RIGHT OPTION-"); } } while(ch!=4); getch(); closegraph(); } void translate() { int p[4][4]; int tx,ty,tz,i,j; for(i=0;i<4;i++) for(j=0;j<4;j++) p[i][j]=(i==j); printf("\nEnter The Translating Factor tx : "); scanf("%d",&tx); printf("\nEnter The Translating Factor ty : "); scanf("%d",&ty); printf("\nEnter The Translating Factor tz : "); scanf("%d",&tz); clrscr(); cleardevice(); display(); p[0][3]=tx; p[1][3]=ty; p[2][3]=tz; matrixmul(p); } void scaling() { int p[4][4]; int sx,sy,sz,i,j; 4

for(i=0;i<4;i++) for(j=0;j<4;j++) p[i][j]=(i==j); printf("\nEnter The Scaling Factor sx : "); scanf("%d",&sx); printf("\nEnter The Scaling Factor sy : "); scanf("%d",&sy); printf("\nEnter The Scaling Factor sz : "); scanf("%d",&sz); if(sx==0) sx=1; if(sy==0) sy=1; if(sz==0) sz=1; clrscr(); cleardevice(); p[0][0]=sx; p[1][1]=sy; p[2][2]=sz; p[3][3]=1; matrixmul(p); } void rotation() { float res[4][1],p[4][4],t[4][1]; int ang,i,j,k,l,rch; float rad; for(i=0;i<4;i++) for(j=0;j<4;j++) p[i][j]=(i==j); printf("\nEnter The Rotating Angle : "); scanf("%d",?); rad=ang*0.0174; printf("\nChoose the axis of roration "); printf("\n1.X-axis"); printf("\n2.Y-axis"); printf("\n3.Z-axis"); printf("\nEnter Your Choice : "); scanf("%d",&rch); switch(rch) { case 1 : p[1][1]=cos(rad); p[1][2]=(-1)*sin(rad); p[2][1]=sin(rad); p[2][2]=cos(rad); break; case 2 : p[0][0]=cos(rad); 5

p[2][0]=(-1)*sin(rad); p[0][2]=sin(rad); p[2][2]=cos(rad); break; case 3 : p[0][0]=cos(rad); p[0][1]=(-1)*sin(rad); p[1][0]=sin(rad); p[1][1]=cos(rad); break; default : printf("\nInvalid Choice !"); } clrscr(); cleardevice(); for(i=0;i<2;i++) { t[0][0]=xp[i]; t[1][0]=yp[i]; t[2][0]=z; t[3][0]=1; for(j=0;j<4;j++) { for(k=0;k<1;k++) { res[j][k]=0; for(l=0;l<4;l++) { res[j][k]=res[j][k]+(p[j][l]*t[l][k]); } } } xp[i]=res[0][0]; yp[i]=res[1][0]; z=res[2][0]; } display(xp,yp); } void display(int xp[2],int yp[2]) { int x3,y3,x4,y4; line(getmaxx()/2,0,getmaxx()/2,getmaxy()); line(0,getmaxy()/2,getmaxx(),getmaxy()/2); outtextxy(getmaxx()/2+5,getmaxy()/2+5,"(0,0)"); outtextxy(getmaxx()-50,getmaxy()/2+10,"X-Axis"); outtextxy(getmaxx()/2+10,20,"Y-Axis"); outtextxy(10,getmaxy()/2+10,"X'-Axis"); outtextxy(getmaxx()/2+10,getmaxy()-20,"Y'-Axis"); 6

rectangle(getmaxx()/2+xp[0],getmaxy()/2-yp[0],getmaxx()/2+xp[1],getmaxy()/2-yp[1]); if(z>=xp[0]) { x3=z+xp[0]; y3=z+yp[0]; x4=z+xp[1]; y4=z+yp[1]; rectangle(getmaxx()/2+x3,getmaxy()/2-y3,getmaxx()/2+x4,getmaxy()/2-y4); line(getmaxx()/2+xp[0],getmaxy()/2-yp[0],getmaxx()/2+x3,getmaxy()/2-y3); line(getmaxx()/2+xp[1],getmaxy()/2-yp[1],getmaxx()/2+x4,getmaxy()/2-y4); line(getmaxx()/2+xp[0],getmaxy()/2-yp[1],getmaxx()/2+x3,getmaxy()/2-y4); line(getmaxx()/2+xp[1],getmaxy()/2-yp[0],getmaxx()/2+x4,getmaxy()/2-y3); } else { x3=xp[0]-z; y3=yp[0]-z; x4=xp[1]-z; y4=yp[1]-z; rectangle(getmaxx()/2+x3,getmaxy()/2-y3,getmaxx()/2+x4,getmaxy()/2-y4); line(getmaxx()/2+xp[0],getmaxy()/2-yp[0],getmaxx()/2+x3,getmaxy()/2-y3); line(getmaxx()/2+xp[1],getmaxy()/2-yp[1],getmaxx()/2+x4,getmaxy()/2-y4); line(getmaxx()/2+xp[0],getmaxy()/2-yp[1],getmaxx()/2+x3,getmaxy()/2-y4); line(getmaxx()/2+xp[1],getmaxy()/2-yp[0],getmaxx()/2+x4,getmaxy()/2-y3); } } void matrixmul(int a[4][4]) { float res[4][1],b[4][1]; int i,j,k,l; for(i=0;i<2;i++) { b[0][0]=xp[i]; b[1][0]=yp[i]; b[2][0]=z; b[3][0]=1; for(j=0;j<4;j++) { for(k=0;k<1;k++) { res[j][k]=0; for(l=0;l<4;l++) { res[j][k]=res[j][k]+(a[j][l]*b[l][k]); } } } xp[i]=res[0][0]; yp[i]=res[1][0]; } 7

z=res[2][0]; display(xp,yp); }

Program 2: Point Clipping Algorithm /********************************************************************* Name: Atishay Jain Subject: Computer Graphics Roll No: 10783017 Program: Point Clipping *********************************************************************/ #include #include #include class pointclip { private: int x[10],y[10],a[10],b[10],c[10],d[10],n; public: void drawrect(); void getpixeldata(); void result(); }clip; void pointclip::drawrect() { int gd=DETECT,gm; initgraph(&gd,&gm,”c:\\tc\\bgi”); cout<<”Enter the coordinates of rectangle”; cin>>x[1]>>y[1]>>x[2]>>y[2]; rectangle(x[1],y[1],x[2],y[2]); getch(); } void pointclip::getpixeldata() { cout<<”Enter the total nymber of pixels want to plot:\n:”; cin>>n; for(int i=1;i<=n;i++) { cout<<”Enter the pixel position(x,y)”<<<”;”; cin>>a[i]>>b[i]; putpixel(a[i],b[i],15); } } void pointclip::result() { cleardevice(); cout<<”Result for the point clipping program:”; 8

rectangle(x[1],y[1],x[2],y[2]); for(int i=1;i<=n;i++) if((a[i]<=x[2]&&a[i]>=x[i]&&b[i]<=y[2]&&b[i]>=y[i])) putpixel(a[i],b[i],15); getch(); closegraph(); } void main() { clip.drawrect(); clip.getpixeldata(); clip.result(); }

Program 3: Cohen Sutherland Line Clipping Algorithm /********************************************************************* Name: Atishay Jain Subject: Computer Graphics Roll No: 10783017 Program: Cohen-Sutherland *********************************************************************/ #include<stdio.h> #include #include typedef unsigned int outcode; enum { TOP=0x1, BOTTOM=0x2, RIGHT=0x4, LEFT=0x8 }; void lineclip(x0,y0,x1,y1,xwmin,ywmin,xwmax,ywmax ) float x0,y0,x1,y1,xwmin,ywmin,xwmax,ywmax; { int gd,gm; outcode code0,code1,codeout; int accept = 0, done=0; code0 = calcode(x0,y0,xwmin,ywmin,xwmax,ywmax); code1 = calcode(x1,y1,xwmin,ywmin,xwmax,ywmax); do{ if(!(code0 | code1)) { accept =1 ; done =1; } else if(code0 & code1) done = 1; else { float x,y; codeout = code0 ? code0 : code1; if(codeout & TOP) 9

{ x = x0 + (x1-x0)*(ywmax-y0)/(y1-y0); y = ywmax; } else if( codeout & BOTTOM) { x = x0 + (x1-x0)*(ywmin-y0)/(y1-y0); y = ywmin; } else if ( codeout & RIGHT) { y = y0+(y1-y0)*(xwmax-x0)/(x1-x0); x = xwmax; } else { y = y0 + (y1-y0)*(xwmin-x0)/(x1-x0); x = xwmin; } if( codeout == code0) { x0 = x; y0 = y; code0=calcode(x0,y0,xwmin,ywmin,xwmax,ywmax); } else { x1 = x; y1 = y; code1 = calcode(x1,y1,xwmin,ywmin,xwmax,ywmax); } } } while( done == 0); if(accept) line(x0,y0,x1,y1); rectangle(xwmin,ywmin,xwmax,ywmax); getch(); } int calcode (x,y,xwmin,ywmin,xwmax,ywmax) float x,y,xwmin,ywmin,xwmax,ywmax; { int code =0; if(y> ywmax) code |=TOP; else if( y xwmax) code |= RIGHT; else if ( x< xwmin) code |= LEFT; 10

return(code); } main() { float x2,y2,x1,y1,xwmin,ywmin,xwmax,ywmax; int gd=DETECT,gm; clrscr(); initgraph(&gd,&gm,"c:\\tc\\bgi"); printf("\n\n\tEnter the co-ordinates of Line :"); printf("\n\n\tX1 Y1 : "); scanf("%f %f",&x1,&y1); printf("\n\n\tX2 Y2 : "); scanf("%f %f",&x2,&y2); printf("\n\tEnter the co_ordinates of window :\n "); printf("\n\txwmin , ywmin : "); scanf("%f %f",&xwmin,&ywmin); printf("\n\txwmax , ywmax : "); scanf("%f %f",&xwmax,&ywmax); clrscr(); line(x1,y1,x2,y2); rectangle(xwmin,ywmin,xwmax,ywmax); getch(); clrscr(); lineclip(x1,y1,x2,y2,xwmin,ywmin,xwmax,ywmax ); getch(); closegraph(); }

Program 4: Liang Barsky Line Clipping Algorithm /********************************************************************* Name: Atishay Jain Subject: Computer Graphics Roll No: 10783017 Program: Liang-Barsky Line Clipping Algorithm *********************************************************************/ #include #include<dos.h> #include #include<stdlib.h> void main() { int gd, gm ; int x1 , y1 , x2 , y2 ; int wxmin,wymin,wxmax, wymax ; float u1 = 0.0,u2 = 1.0 ; int p1 , q1 , p2 , q2 , p3 , q3 , p4 ,q4 ; float r1 , r2 , r3 , r4 ; int x11 , y11 , x22 , y22 ; 11

clrscr(); printf("Enter the windows left xmin , top boundry ymin\n"); scanf("%d%d",&wxmin,&wymin); printf("Enter the windows right xmax ,bottom boundry ymax\n"); scanf("%d%d",&wxmax,&wymax); printf("Enter line x1 , y1 co-ordinate\n"); scanf("%d%d",&x1,&y1); printf("Enter line x2 , y2 co-ordinate\n"); scanf("%d%d",&x2,&y2); printf("liang barsky express these 4 inequalities using lpk<=qpk\n"); p1 = -(x2 - x1 ); q1 = x1 - wxmin ; p2 = ( x2 - x1 ) ; q2 = wxmax - x1 ; p3 = - ( y2 - y1 ) ; q3 = y1 - wymin ; p4 = ( y2 - y1 ) ; q4 = wymax - y1 ; printf("p1=0 line is parallel to left clipping\n"); printf("p2=0 line is parallel to right clipping\n"); printf("p3=0 line is parallel to bottom clipping\n"); printf("p4=0 line is parallel to top clipping\n"); if( ( ( p1 == 0.0 ) && ( q1 < 0.0 ) ) || ( ( p2 == 0.0 ) && ( q2 < 0.0 ) ) || ( ( p3 == 0.0 ) && ( q3 < 0.0 ) ) || ( ( p4 == 0.0 ) && ( q4 < 0.0 ) ) ) { printf("Line is rejected\n"); getch(); detectgraph(&gd,&gm); initgraph(&gd,&gm,"c:\\tc\\bgi"); setcolor(RED); rectangle(wxmin,wymax,wxmax,wymin); setcolor(BLUE); line(x1,y1,x2,y2); getch(); setcolor(WHITE); line(x1,y1,x2,y2); getch(); } else { if( p1 != 0.0 ) { r1 =(float) q1 /p1 ; if( p1 < 0 ) u1 = max(r1 , u1 ); else u2 = min(r1 , u2 ); } if( p2 != 0.0 ) { r2 = (float ) q2 /p2 ; if( p2 < 0 ) u1 = max(r2 , u1 ); else u2 = min(r2 , u2 ); 12

} if( p3 != 0.0 ) { r3 = (float )q3 /p3 ; if( p3 < 0 ) u1 = max(r3 , u1 ); else u2 = min(r3 , u2 ); } if( p4 != 0.0 ) { r4 = (float )q4 /p4 ; if( p4 < 0 ) u1 = max(r4 , u1 ); else u2 = min(r4 , u2 ); } if( u1 > u2 ) printf("line rejected\n"); else { x11 = x1 + u1 * ( x2 - x1 ) ; y11 = y1 + u1 * ( y2 - y1 ) ; x22 = x1 + u2 * ( x2 - x1 ); y22 = y1 + u2 * ( y2 - y1 ); printf("Original line cordinates\n"); printf("x1 = %d , y1 = %d, x2 = %d, y2 = %d\n",x1,y1,x2,y2); printf("Windows coordiante are \n"); printf("wxmin = %d, wymin = %d,wxmax = %d , wymax = %d ",wxmin,wymin,wxmax,wymax); printf("New coordinates are \n"); printf("x1 = %d, y1 = %d,x2 = %d , y2 = %d\n",x11,y11,x22,y22); detectgraph(&gd,&gm); initgraph(&gd,&gm,"C:\\TC\\BGI"); setcolor(2); rectangle(wxmin,wymax,wxmax,wymin); setcolor(1); line(x1,y1,x2,y2); getch(); setcolor(0); line(x1,y1,x2,y2); setcolor(3); line(x11,y11,x22,y22); getch(); }}}

Program 5: Sutherland Hodgeman Polygon Clipping Algorithm 13

/********************************************************************* Name: Atishay Jain Subject: Computer Graphics Roll No: 10783017 Program: Sutherland Hodgeman *********************************************************************/ #include #include #include #define MAXVERTICES 11 #define MAXCORDINATES ((MAXVERTICES * 2) + 1) int corArray[MAXCORDINATES],nVertices=0; int corArray2[MAXCORDINATES],nVertices2=0; int wx_min,wx_max,wy_min,wy_max; enum boundry {left=0,right,bottom,top}; void initialize() { int gDriver = DETECT,gMode; initgraph(&gDriver,&gMode,"C:\\tc\\bgi"); cleardevice(); } void inputPolygon() { cout<<"\nEnter No of Vertices (Min. 3,Max. "<<MAXVERTICES<<"): "; cin>>nVertices; if(nVertices < 3 || nVertices > MAXVERTICES) nVertices = 3; for(int i=0;i>corArray[2*i]>>corArray[(2*i)+1]; } corArray[2*(nVertices)] = corArray[0]; corArray[(2*(nVertices))+1] = corArray[1]; } void samplePolygon() { int midx = getmaxx()/2; int midy = getmaxy()/2; int polygon_vertices[]={ midx,midy-125, midx-200,midy-50, midx-75,midy-50, midx-75,midy+200, midx+75,midy+200, midx+75,midy-50, midx+200,midy-50, midx,midy-125}; nVertices = 8; 14

for(int i = 0;i wx_min); case right: return (x < wx_max); case bottom: return (y < wy_min); case top: return (y > wy_max); } return 0; } int calcCondition(int x1,int y1,int x2,int y2,boundry b) { int stat1 = insideWindow(x1,y1,b); int stat2 = insideWindow(x2,y2,b); if(!stat1 && stat2) return 1; if(stat1 && stat2) return 2; if(stat1 && !stat2) return 3; if(!stat1 && !stat2) return 4; return 0; //never executed } void solveIntersection(boundry b,int x1,int y1,int x2,int y2,int &x,int &y) { float m = 0; if(x2 != x1) m = ((float)(y2-y1)/(float)(x2-x1)); switch(b) { case left: x = wx_min; y = y1 + m * (x - x1); break; case right: x = wx_max; y = y1 + m * (x - x1); break; case bottom: y = wy_min; if(x1 != x2) x = x1 + (float)(1/m) * (y - y1); else x = x1; 15

break; case top: y = wy_max; if(x1 != x2) x = x1 + (float)(1/m) * (y - y1); else x = x1; break; } } void addNewPoint(int x,int y) { corArray2[(2 * nVertices2)] = x; corArray2[(2 * nVertices2)+1] = y; nVertices2++; } void clipPolygon() { int j,k; boundry i; for(i=left;i<=top;i++) { nVertices2 = 0; for(j=0;j
} addNewPoint(corArray2[0],corArray2[1]); //update corArray and nvertices... nVertices = nVertices2; for(j=0;j>wx_min>>wx_max>>wy_min>>wy_max; rectangle(wx_min,wy_max,wx_max,wy_min); drawpoly(nVertices+1,corArray); getch(); clipPolygon(); clrscr(); cleardevice(); rectangle(wx_min,wy_max,wx_max,wy_min); drawpoly(nVertices+1,corArray); getch(); }

Program 6: Perspective Projections /********************************************************************* Name: Atishay Jain Subject: Computer Graphics Roll No: 10783017 Program: Perspective Projection *********************************************************************/ #include<stdio.h> #include<math.h> #include main() { int x1,y1,x2,y2,gd,gm; int ymax,a[4][8]; float par[4][4],b[4][8]; 17

int i,j,k,m,n,p; int xp, yp, zp, x, y, z; a[0][0] = 100; a[1][0] = 100; a[2][0] = -100; a[0][1] = 200; a[1][1] = 100; a[2][1] = -100; a[0][2] = 200; a[1][2] = 200; a[2][2] = -100; a[0][3] = 100; a[1][3] = 200; a[2][3] = -100; a[0][4] = 100; a[1][4] = 100; a[2][4] = -200; a[0][5] = 200; a[1][5] = 100; a[2][5] = -200; a[0][6] = 200; a[1][6] = 200; a[2][6] = -200; a[0][7] = 100; a[1][7] = 200; a[2][7] = -200; detectgraph(&gd,&gm); initgraph(&gd,&gm, "c:\\tc\\bgi"); ymax = getmaxy(); xp = 300; yp = 320; zp = 100; for(j=0; j<8; j++) { x = a[0][j]; y = a[1][j]; z = a[2][j]; b[0][j] = xp - ( (float)( x - xp )/(z - zp)) * (zp); b[1][j] = yp - ( (float)( y - yp )/(z - zp)) * (zp); } /*- front plane display -*/ for(j=0;j<3;j++) { x1=(int) b[0][j]; y1=(int) b[1][j]; x2=(int) b[0][j+1]; y2=(int) b[1][j+1]; line( x1,ymax-y1,x2,ymax-y2); } x1=(int) b[0][3]; y1=(int) b[1][3]; x2=(int) b[0][0]; y2=(int) b[1][0]; line( x1, ymax-y1, x2, ymax-y2); /*- back plane display -*/ setcolor(11); for(j=4;j<7;j++) { x1=(int) b[0][j]; y1=(int) b[1][j]; x2=(int) b[0][j+1]; y2=(int) b[1][j+1]; line( x1, ymax-y1, x2, ymax-y2); } x1=(int) b[0][7]; y1=(int) b[1][7]; x2=(int) b[0][4]; y2=(int) b[1][4]; line( x1, ymax-y1, x2, ymax-y2); setcolor(7); for(i=0;i<4;i++) { 18

x1=(int) b[0][i]; y1=(int) b[1][i]; x2=(int) b[0][4+i]; y2=(int) b[1][4+i]; line( x1, ymax-y1, x2, ymax-y2); } getch(); }

Program 7: Parallel Projections /********************************************************************* Name: Atishay Jain Subject: Computer Graphics Roll No: 10783017 Program: Oblique Projection *********************************************************************/ #include<stdio.h> #include<math.h> #include main() { int x1,y1,x2,y2,gd,gm; int ymax,a[4][8]; float par[4][4],b[4][8]; int i,j,k,m,n,p; double L1,phi; a[0][0] = 100; a[1][0] = 100; a[2][0] = 100; a[0][1] = 200; a[1][1] = 100; a[2][1] = 100; a[0][2] = 200; a[1][2] = 200; a[2][2] = 100; a[0][3] = 100; a[1][3] = 200; a[2][3] = 100; a[0][4] = 100; a[1][4] = 100; a[2][4] = 200; a[0][5] = 200; a[1][5] = 100; a[2][5] = 200; a[0][6] = 200; a[1][6] = 200; a[2][6] = 200; a[0][7] = 100; a[1][7] = 200; a[2][7] = 200; phi = (double) (3.14*45.0)/180 ; L1 = 0.5; par[0][0] = 1; par[0][1] = 0; par[0][2] = L1*cos(phi); par[0][3] = 0; par[1][0] = 0; par[1][1] = 1; par[1][2] = L1*sin(phi); par[1][3] = 0; par[2][0] = 0; par[2][1] = 0; par[2][2] = 0; par[2][3] = 0; par[3][0] = 0; par[3][1] = 0; 19

par[3][2] = 0; par[3][3] = 1; m=4; n=4; p=8; for(i=0; i<m; i++) for(k=0; k
}

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