Cs2405 Cg Lab

1

COMPUTER GRAPHICSCS2405

LAB MANUAL

INDEX

www.rejin

paul.

com

2

SN TITLE PAGE

1A Line Drawing Using Bresenham Algorithm

1B Circle Drawing Using Bresenham Algorithm

1C Ellipse Drawing Using Bresenham Algorithm

2 . Implementation of Line, Circle and ellipse Attributes

3 Two Dimensional Transformations

4

5 Cohen Sutherland 2D line clipping and Windowing

6

7 . Three dimensional transformations

8

9

10

www.rejin

paul.

com

3

SYLLABUS

COMPUTER GRAPHICS LABORATORY

CS2405

1. Implementation of Bresenhams Algorithm – Line, Circle, Ellipse.

2. Implementation of Line, Circle and ellipse Attributes

3. Two Dimensional transformations - Translation, Rotation, Scaling, Reflection,

Shear.

4. Composite 2D Transformations

5. Cohen Sutherland 2D line clipping and Windowing

6. Sutherland – Hodgeman Polygon clipping Algorithm

7. Three dimensional transformations - Translation, Rotation, Scaling

8. Composite 3D transformations

9. Drawing three dimensional objects and Scenes

10. Generating Fractal images TOTAL: 45 PERIODS

LIST OF EQUIPMENTS:

1) Turbo C

2) Visual C++ with OPENGL

3) Any 3D animation software like 3DSMAX, Maya, Blender

LINE DRAWING USING BRESENHAM ALGORITHM

EX.NO: 1A

www.rejin

paul.

com

4

DATE:

AIM:

To write a C program for Line Drawing Using Bresenham Algorithm.

ALGORITHM:

Step 1 : Start the program.

Step 2 : Declare the necessary variables.

Step 3 : Initialize the graph using dx, dy, gd, gm.

Step 4 : Assign the values of x1, y1 to x,y respectively.

Step 5 : Similarly, absolute values to dx, dy.

Step 6 : put pixel and set 15 to pixel position.

Step 7 : Using do-while loop, put e,x,y,I values.

Step 8 : Stop the program.

PROGRAM:

#include<stdio.h>

#include<conio.h>

www.rejin

paul.

com

5

#include<dos.h>

#include<math.h>

#include<graphics.h>

void main()

{

float x,y,x1,y1,x2,y2,dx,dy,e;

int i,gd=DETECT,gm;

clrscr();

printf("\n ENTER THE VALUE OF X1:");

scanf("%f",&x1);

printf("\n ENTER THE VALUES OF Y1:");

scanf("%f",&y1);

printf("\n ENTER THE VALUES OF X2 AND Y2:");

scanf("%f%f",&x2,&y2);

initgraph(&gd,&gm," ");

dx=abs(x2-x1);

dy=abs(y2-y1);

x=x1;

y-y1;

e=2*(dy-dx);

i=1;

do

{

putpixel(x,y,15);

while(e>=0)

{

y=y+1;

e=e-(2*dx);

}

x=x+1;

e=e+(2*dy);

i=i+1;

delay(100);

}while(i<=dx);

closegraph();

www.rejin

paul.

com

6

getch();

}

OUTPUT:

ENTER THE VALUE OF X1 : 600

ENTER THE VALUE OF Y1 : 400

ENTER THE VALUE OF X2 AND Y2 : 300 400

CIRCLE DRAWING USING BRESENHAM ALGORITHM

Ex. No : 1B

Date :

AIM:

www.rejin

paul.

com

7

To write a C program for Circle Drawing Using Bresenham Algorithm.

ALGORITHM:

Step 1 : Start the program.

Step 2 : Declare the necessary variables.

Step 3 : Create the function for Circle.

Step 4 : Enter the radius and center values.

Step 5 : Initialize the graph with gd, gm and assign y<-radius.

Step 6 : Start the circle function and p<- 1- radius.

Step 7 : Check the while loop until the condition is satisfied.

Step 8 : Check the if –else condition until the condition is satisfied.

Step 9 : Assign all operation for circle function and the values.

Step 10 : Stop the Program.

PROGRAM:

#include<stdio.h>

#include<conio.h>


void circlefun(int xcenter, int ycenter,int x,int y);

void main()

{

int x=0,radius,xcenter,ycenter;

int y,p,gd=DETECT,gm;

clrscr();


printf("\n ENTER THE XCENTER &YCENTER:");

scanf("%d%d",&xcenter,&ycenter);

printf("\n ENTER THE RADIUS:");

scanf("%d",&radius);

y=radius;

circlefun(xcenter,ycenter,x,y);

p=1-radius;

www.rejin

paul.

com

8

while(x<y)

{

if(p<0)

x=x+1;

else

{

x=x+1;

y=y-1;

}

if(p<0)

p=p+2*x+1;

else

p=p+2*(x-y)+1;

circlefun(xcenter,ycenter,x,y);

}

getch();

}

void circlefun(int xcenter,int ycenter,int x,int y)

{

putpixel(xcenter+x,ycenter+y,1);

putpixel(xcenter-x,ycenter+y,1);

putpixel(xcenter+x,ycenter-y,1);

putpixel(xcenter-x,ycenter-y,1);

putpixel(xcenter+y,ycenter+x,1);

putpixel(xcenter-y,ycenter+x,1);

putpixel(xcenter+y,ycenter-x,1);

putpixel(xcenter-y,ycenter-x,1);

}

OUTPUT:

ENTER THE X CENTER AND Y CENTER : 500 250

www.rejin

paul.

com

9

ENTER THE RADIUS : 70

RESULT:

Thus the above program “CIRCLE DRAWING USING BREASENHAM” is executed

successfully.

ELLIPSE DRAWING USING BRESENHAM ALGORITHM

Ex. No : 1C

Date :

AIM:

To write a C program for Circle Drawing Using Bresenham Algorithm.

www.rejin

paul.

com

10

ALGORITHM:

Step 1: Start the program.

Step 2: Initialize the variables.

Step 3: Call the initgraph() function.

Step 4: Get the initialize points P1,P2.

Step 5: Get the values of Co-Ordinates of the ellipse (x,y).

Step 6: Enter the coordinates a,b of the ellipse .

Step 7: Display the output.

Step 8: Stop the program

PROGRAM

#include<stdio.h>

#include<conio.h>


#include<math.h>

void disp();

float x,y;

int xc,yc;

void main()

{

int gd=DETECT,gm;

int a,b;

float p1,p2;

clrscr();

initgraph(&gd,&gm,"");

scanf("%d%d",&xc,&yc);

scanf("%d%d",&a,&b);

x=0;y=b;

disp();

p1=(b*b)-(a*a*b)+(a*a)/4;

while((2.0*b*b*x)<=(2.0*a*a*y))

{

x++;

www.rejin

paul.

com

http://studentwebsite.blogspot.com/2009/10/ellipse-drawing-algorithm-in-c-program.html

11

if(p1<=0)

p1=p1+(2.0*b*b*x)+(b*b);

else

{

y--;

p1=p1+(2.0*b*b*x)+(b*b)-(2.0*a*a*y);

}

disp();

x=-x;

disp();

x=-x;

}

x=a;

y=0;

disp();

p2=(a*a)+2.0*(b*b*a)+(b*b)/4;

while((2.0*b*b*x)>(2.0*a*a*y))

{

y++;

if(p2>0)

p2=p2+(a*a)-(2.0*a*a*y);

else

{

x--;

p2=p2+(2.0*b*b*x)-(2.0*a*a*y)+(a*a);

}

disp();

y=-y;

disp();

y=-y;

}

getch();

closegraph();

}

void disp()

www.rejin

paul.

com

12

{

putpixel(xc+x,yc+y,10);

putpixel(xc-x,yc+y,10);

putpixel(xc+x,yc-y,10);

putpixel(xc+x,yc-y,10);

}

INPUT

Ellipse Drawing Algorithm

Enter the co-ordinates

Xc = 200

Yc = 200

A = 100

B = 70

OUTPUT

Result:

www.rejin

paul.

com

http://studentwebsite.blogspot.com/2009/10/ellipse-drawing-algorithm-in-c-program.html

http://4.bp.blogspot.com/_Gmn-kEVg3hk/SciNd6U29yI/AAAAAAAAAYk/g20WQMLr8rg/s1600-h/Graphics+and+multimedia+Lab+Bresenhams++Ellipse+Drawing+Algorithm+c+program.JPG

13

Thus using C++ program implementation of Bresenham’s algorithm for line, circle and

ellipse drawing is done.

TWO DIMENSIONAL TRANSFORMATIONS

www.rejin

paul.

com

Ex. No. : 3Date :

14

AIM:

To write a C program for Two Dimensional Transformations.

ALGORITHM:


Step 2: Declare the necessary variables and initialize the graph, gd, gm.

Step 3: Use do-while loop and declare the function clear device.

Step 4: Create four cases translation, scaling , rotation and exit.

Step 5: In case 1 enter the translation values and print the translation

object.

Step 6: In case 2 enter the scaling values and print the scaling object.

Step 7: In case 3 enter the rotaion values and print rotation object.

Step 8: Clockwise rotation and counter clockwise rotation use the same

equation.

Step 9: Stop the program.

PROGRAM:

#include<stdio.h>

#include<conio.h>


#include<math.h>

#include<stdlib.h>

void main()

{

www.rejin

paul.

com

15

int x,y,c;

float a;

int gd=DETECT,gm;


do

{

cleardevice();

printf("1.TRANSLATION 2.SCALING 3.ROTATION

4.EXIT");

printf("\n ENTER YR CHOICE:");

scanf("%d",&c);

switch(c)

{

case 1:

rectangle(100,200,300,300);

printf("\nENTER THE TX AND TY VALUE:");

scanf("%d%d",&x,&y);

outtextxy(130,180," ORIGINAL OBJECT");

rectangle(100+x,200+y,300+x,300+y);

outtextxy(130+x,180," TRANSLATION

OBJECT");

break;

case 2:

rectangle(50,100,150,150);

printf("\n ENTER THE SX AND SY

VALUE:");


outtextxy(38,85,"ORIGINAL OBJECT");

rectangle(50*x,100*y,150*x,150*y);

outtextxy(250,250,"SCALING OBJECT");

break;

case 3:

printf("\n ENTER THE X AND Y VALUE:");


www.rejin

paul.

com

16

printf("\n ENTER THE ANGLE;");

scanf("%d",&c);

a=(3.14*c)/180;

cleardevice();

line(100,100,200,100);

outtextxy(210,100,"ORIGINAL OBJECT");

line(100*cos(a)-100*sin(a)+x*(1-cos(a))

+y*sin(a),100*sin(a)+100*cos(a)+y*(1-cos(a))

-x*sin(a),200*cos(a)-100*sin(a)+x*(1-cos(a))

+y*sin(a),200*sin(a)+100*cos(a)+y*(1-cos(a))

-x*sin(a));

outtextxy(110,75,"COUNTER CLOCKWISE

ROTATION");

line(100*cos(a)+100*sin(a)+x*(1-cos(a))

-y*sin(a),-100*sin(a)+100*cos(a)+y*(1-cos(a))

+x*sin(a),200*cos(a)+100*sin(a)+x*(1-cos(a))

-y*sin(a),-200*sin(a)+100*cos(a)+y*(1-cos(a))

+x*sin(a));

outtextxy(110,150,"CLOCKWISE ROTATION");

getch();

break;

case 4:

exit(0);

}

getch();

}while(c!=4);

} www.rejin

paul.

com

17

OUTPUT:

1.TRANSLATION 2. SCALING 3. ROTATION 4. EXIT

ENTER YOUR OPTION : 1

ENTER THE TX AND TY VALUE : 150 150

ORIGINAL OBJECT TRANSLATION OBJECT

1. TRANSLATION 2.SCALING 3. ROTATION 4. EXIT


ENTER YOUR SX AND SY VALUE : 2 2

1. TRANSLATION 2.SCALING 3. ROTATION 4. EXIT


ENTER THE X AND Y VALUE :100 100

ENTER THE ANGLE :90

COUNTER CLOCKWISE

ROTATION

ORIGINAL OBJECT CLOCKWISE ROTATION

www.rejin

paul.

com

18

RESULT:

Thus the above program”TWO DIMENSIONAL

TRANSFORMATIONS” Is executed successfully.

COHEN SUTHERLAND 2D LINE CLIPPING AND WINDOWING

Ex. No : 5

www.rejin

paul.

com

19

Date :

AIM:

To implement cohen-sutherland 2d clipping and window-view port

mapping

COHEN-SUTHERLAND 2D LINE CLIPPING

#include<stdio.h>

#include<conio.h>


#include<math.h>

float cxl,cxr,cyt,cyb;

code(float ,float);

void clip(float ,float,float,float);

void rect(float ,float,float,float);

main()

{

float x1,y1,x2,y2;

int g=0,d;

initgraph(&g,&d,"c:\\tc\\bin");

settextstyle(1,0,1);

outtextxy(40,15,"BEFORE CLIPPING");

printf("\n Please Enter Left,Bottom,Right,Top Of Clip Window");

scanf("%f%f%f%f",&cxl,&cyb,&cxr,&cyt);

rect(cxl,cyb,cxr,cyt);

getch();

printf("\n Enter The Line Coordinate");

scanf("%f%f%f%f",&x1,&y1,&x2,&y2);

line(x1,y1,x2,y2);

getch();

cleardevice();

www.rejin

paul.

com

20

settextstyle(1,0,1);

outtextxy(40,15,"AFTER CLIPPING");

clip(x1,y1,x2,y2);

getch();

closegraph();

}

void clip(float x1,float y1,float x2,float y2)

{

int c,c1,c2;

float x,y;

c1=code(x1,y1);

c2=code(x2,y2);

getch();

while((c1!=0)||(c2!=0))

{

if((c1&c2)!=0)

goto out;

c=c1;

if(c==0)

c=c2;

if((c&1)==1)

{

y=y1+(y2-y1)*(cxl-x1);

x=cxl;

}

else

if((c&2)==2)

{

y=y1+(y2-y1)*(cxl-x1)/(x2-x1);

x=cxr;

}

www.rejin

paul.

com

21

else

if((c&8)==8)

{

x=x1+(x2-x1)*(cyb-y1)/(y2-y1);

y=cyb;

}

else

if((c&4)==4)

{

x=x1+(x2-x1)*(cyt-y1)/(y2-y1);

y=cyt;

}

if(c==c1)

{

x1=x;

y1=y;

c1=code(x,y);

}

else

{

x2=x;

y2=y;

c2=code(x,y);

}

}

out:

rect(cxl,cyb,cxr,cyt);

line(x1,y1,x2,y2);

}

code(float x ,float y)

{

int c=0;

if(x<cxl) c=1;

www.rejin

paul.

com

22

else

if(x>cxr) c=2;

else

if(y<cyb) c=c|8;

else

if(y>cyt) c=c|4;

return c;

}

void rect(float xl,float yb,float xr,float yt)

{

line(xl,yb,xr,yb);

line(xr,yb,xr,yt);

line(xr,yt,xl,yt);

line(xl,yt,xl,yb);

}

OUTPUT

SAMPLE INPUT:

Please Enter Left , Bottom , Right , Top Of The Clip window

200

200

400

400

Please Enter The Line Coordinates (X1, Y1, X2, Y2)

150

300

400

www.rejin

paul.

com

23

450

SAMPLE OUTPUT:

BEFORE CLIPPING

AFTER CLIPPING:

Windowing To Viewport Mapping

www.rejin

paul.

com

24

#include<stdio.h>

#include<conio.h>


#include<math.h>

main()

{

float sx,sy;

int w1,w2,w3,w4,x1,x2,x3,x4,y1,y2,y3,y4,v1,v2,v3,v4;

int gd=DETECT,gm;

initgraph(&gd,&gm,"c:\\tc\\bgi");

printf("Enter The Coordinate x1,y1,x2,y2,x3,y3\n");

scanf("%d%d%d%d%d%d",&x1,&y1,&x2,&y2,&x3,&y3);

cleardevice();

w1=5;

w2=5;

w3=635;

w4=465;

rectangle(w1,w2,w3,w4);

line(x1,y1,x2,y2);

line(x2,y2,x3,y3);

line(x3,y3,x1,y1);

getch();

v1=425;

v2=75;

v3=550;

v4=250;

sx=(float)(v3-v1)/(w3-w1);

sy=(float)(v4-v2)/(w4-w2);

rectangle(v1,v2,v3,v4);

x1=v1+floor(((float)(x1-w1)*sx)+.5);



y1=v2+floor(((float)(y1-w2)*sy)+.5);


www.rejin

paul.

com

25


line(x1,y1,x2,y2);

line(x2,y2,x3,y3);

line(x3,y3,x1,y1);

getch();

return 0;

}

SAMPLE INPUT:

Enter The Coordinate x1,y1,x2,y2,x3,y3

100

200

300

400

500

350

SAMPLE OUTPUT:

www.rejin

paul.

com

26

Result :

www.rejin

paul.

com

Ex. No. : 07Date :

27

TRANSLATION AND SCALING USING 3D

AIM:

To write a C program for Translation and Scaling Using 3D Method.

ALGORITHM:


Step 2: Declare the necessary variables, with member functions.

Step 3: Create the main function, in that function to initialize graph using

do-while statement.

Step 4: Using Switch statement for translation, scaling, exit.

Step 5: Using get function for getting the values.

Step 6: Similarly, get the draw function for draw the lines.

Step 7: Stop the program.

www.rejin

paul.

com

28

PROGRAM:

#include<stdio.h>

#include<conio.h>


#include<math.h>

int n,dep;

float x[10],y[10],nx[10],ny[10];

void translation();

void scaling();

void rotation();

void draw(float x[],float y[]);

void get();

void main()

{

int gd=DETECT,gm,i,ch;


get();

do

{

cleardevice();

draw(x,y);

printf("\n 1.TRANSLATION 2.SCALING 3.EXIT");

printf("\n ENTER UR CHOICE:");

scanf("%d",&ch);

switch(ch)

{

case 1:

translation();

break;

www.rejin

paul.

com

29

case 2:

scaling();

break;

case 3:

closegraph();

exit(0);

}

getch();

}while(ch!=3);

}

void get()

{

int i;

printf("\n ENTER THE NO.OF SIDES& DEPTH OF THE

POLYGON:");

scanf("%d%d",&n,&dep);

printf("n ENTER THE CO ORDINATES\n");

for(i=0;i<n;i++)

{

printf("\n ENTER THE X%d&Y%d VALUE:");

scanf("%f%f",&x[i],&y[i]);

}

}

void draw(float x[],float y[])

{

int i;

for(i=0;i<n-1;i++)

line(x[i],y[i],x[i+1],y[i+1]);

line(x[i],y[i],x[0],y[0]);

for(i=0;i<n-1;i++)

line(x[i]+dep,y[i]-dep,x[i+1]+dep,y[i+1]-dep);

line(x[i]+dep,y[i]-dep,x[0]+dep,y[0]-dep);

for(i=0;i<n;i++)

line(x[i],y[i],x[i]+dep,y[i]-dep);

www.rejin

paul.

com

30

}

void translation()

{

int i,ch;

float tx,ty;

draw(x,y);

printf("ENTER THE TRANSLATIONFACTOR TX &TY

VALUE:");

scanf("%f%f",&tx,&ty);

for(i=0; i<n;i++)

{

nx[i]=x[i]+tx;

ny[i]=y[i]+ty;

}

draw(nx,ny);

}

void scaling()

{

int i,ch;

float sx,sy;

draw(x,y);

printf("ENTER THE SCALING FACTOR SX &SY

VALUE:");

scanf("%f%f",&sx,&sy);

for(i=0;i<n;i++)

{

nx[i]=x[i]*sx;

ny[i]=y[i]*sy;

}

draw(nx,ny);

}

www.rejin

paul.

com

31

OUTPUT:

ENTER THE NO OF SIDES & DEPTH OF THE POLYGON : 4 10

ENTER THE CO-ORDINATES :

ENTER THE X1 AND Y1 VALUES : 200 10




1. TRANSLATION 2. SCALING 3. EXIT

ENTER YOUR CHOICE : 1

ENTER THE TRANSLATION FACTORS TX AND TY VALUES : 100 0

1. TRANSLATION 2. SCALING 3. EXIT

ENTER YOUR CHOICE : 2

ENTER THE SCALING FACTORS SX AND SY VALUES : 2 2

www.rejin

paul.

com

32

RESULT:

Thus the above program TRANSLATION AND SCALING USING 3D” Is executed successfully.

www.rejin

paul.

com

33

www.rejin

paul.

com

34

www.rejin

paul.

com

Documents

Cs2405 Cg Lab