cs computer graphics lab manual

7/28/2019 CS Computer Graphics Lab Manual

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IMPLEMENTATION OF DDA LINE ALGORITHM

DESCRIPTION:

Digital Differential Analyzer (DDA) is used for linear interpolation of variables over aninterval between start and end point of a line. Simplest implementation the DDA algorithm interpolates values

in interval [(xstart, ystart), (xend, yend)] by computing for each x i the equations xi = xi1+1, yi = yi1+ y/x,

Where x = xend xstartand y = yend ystart.

CODING:

#include /* include the necessary header files*/

#include

#include

#include

void draw(int xa,int ya,int xb,int yb);

void main()

{

int xa,ya,xb,yb;

clrscr();

printf("Line DDA algorithm");

printf("\n Enter the value of xa, ya:");

scanf("%d%d",&xa,&ya);

printf("\n Enter the value of xb, yb:");

scanf("%d%d",&xb,&yb);

draw(xa,ya,xb,yb);

}

void draw(int xa,int ya,int xb,int yb)

{

int xin,yin,x,y,dx,dy,steps,k; /* request auto detection */

int gdriver=DETECT,gmode,errorcode; /* initialize graphics and local variables */

initgraph(&gdriver,&gmode, "c:\\tc\\bgi") /* read result of initialization */

errorcode=graphresult(); /* an error occurred */

www.Vidyarthiplus.com

http://en.wikipedia.org/wiki/Digital_differential_analyzerhttp://en.wikipedia.org/wiki/Digital_differential_analyzer


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if (errorcode!=grOk)

{

printf("Graphics error: %s\n", grapherrormsg(errorcode));

printf("Press any key to halt:");getch();

exit(1);

}

dx=xb-xa;

dy=yb-ya;

if(abs(dx)>abs(dy)) /* if the condition is satisfied */

{ /* calculate the value of the condition variable*/

steps=abs(dx);

}

else

{

steps=abs(dy);

}

xin=dx/steps;

yin=dy/steps;

x=xa;

y=ya;

putpixel(x,y,1); /* draw the first pixel for the line*/

for(k=1;k


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OUTPUT:

Line DDA algorithm

Enter the value of xa, ya:400

260

Enter the value of xb, yb:

456

23

RESULT:

Thus the DDA line drawing algorithm was successfully executed and the output is drawn and verified.




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IMPLEMENTATION OF BRESENHAMS LINE ALGORITHM

DESCRIPTION:

The Bresenham line algorithm is an algorithm which determines which points in an n-dimensionalrastershould be plotted in order to form a close approximation to a straight line between two given points. The

endpoints of the line are the pixels at (x0, y0) and (x1, y1), where the first coordinate of the pair is the column and

the second is the row.

CODING:


#include

#include

#include

void draw(int xa, int ya, int xb, int yb);

void main()

{

int xa, ya, xb, yb;

clrscr();

printf("Bresenhnams algorithm"); /* get the coordinates of the line*/

printf("\n Enter the value of xa, ya:");

scanf("%d%d",&xa,&ya);

printf("\n Enter the value of xb, yb:");

scanf("%d%d",&xb,&yb);

draw(xa,ya,xb,yb);

}

void draw(int xa, int ya, int xb, int yb)

{

int x,y,dx,dy,xend,p; /* request auto detection */

int gdriver=DETECT,gmode,errorcode; /* initialize graphics and local variables */

initgraph(&gdriver,&gmode,"c:\\tc\\bgi"); /* read result of initialization */

errorcode=graphresult(); /* an error occurred */


http://en.wikipedia.org/wiki/Algorithmhttp://en.wikipedia.org/wiki/Raster_graphicshttp://en.wikipedia.org/wiki/Raster_graphicshttp://en.wikipedia.org/wiki/Algorithm


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if(errorcode!=grOk)

{



exit(1);

}

dx=xb-xa;

dy=yb-ya;

p=2*dy-dx; /* calculate the value of the condition variable*/

if(xa>xb) /* depending on the position of the coordinates*/

{

x=xb; /* assign the values for (x,y)*/

y=yb;

xend=xa;

}

else if(xb>xa)

{

x=xa;

y=ya;

xend=xb;

}

putpixel(x,y,1); /* draw the pixel on the screen*/

while(x


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y=y+1;

p=p+2*dy;

}

putpixel(x,y,1);} /* clean up */

getch();

closegraph();

}

OUTPUT:

Bresenhams algorithmEnter the value of xa, ya:

150

150Enter the value of xb, yb:

15

150

RESULT:

Thus the Bresenhams line drawing algorithm was successfully executed and the output is drawn and

verified.




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IMPLEMENTATION OF MIDPOINT CIRCLE ALGORITHM

DESCRIPTION:

The MidPoint Circle Algorithm is an algorithm used to determine the points needed for drawing acircle. The algorithm is a variant ofBresenham's line algorithm, and is thus sometimes known as Bresenham's

circle algorithm. Which starts accordingly with the circle equation x2

+ y2

= r2. And with the center of the

circle is located at (0, 0)

CODING:


#include

#include

#include

main()

{

int gd=DETECT,gin;

int xcenter,ycenter,radius;

int p,x,y,twox,twoy; /*request auto detect*/

initgraph(&gd,&gin,"C:\\tc\\bgi");

x=0;

printf("\nEnter the radius value:"); /* get the value of the radius and center values*/

scanf("%d",&radius);

printf("Enter the center values:");

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

plotpoints(xcenter,ycenter,x,y); /* call the plotpoints function*/

y=radius;

p=1-radius;

twox=2*x;

twoy=2*y;

printf("\np\tx\ty\t2x\t2y\n");

printf("\n%d\t%d\t%d\t%d\t%d\n",p,x,y,twox,twoy);


http://en.wikipedia.org/wiki/Bresenham%27s_line_algorithmhttp://en.wikipedia.org/wiki/Circlehttp://en.wikipedia.org/wiki/Circlehttp://en.wikipedia.org/wiki/Bresenham%27s_line_algorithm


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while(x


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OUTPUT:

Enter the Radius value:

10

Enter the Centre values:120

120

RESULT:

Thus the Midpoint circle algorithm was successfully executed and the output is drawn and verified.




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IMPLEMENTATION OF MIDPOINT ELLIPSE ALGORITHM

DESCRIPTION:

The Midpoint Ellipse Algorithm is a method for drawing ellipses in computer graphics this method ismodified from Bresenhams which starts accordingly with the ellipse equation b2x2 + a2y2a2b2 = 0 where a

is the horizontal radius and b is the vertical radius

CODING:


#include

#include

#include

#include

void plotpoints(int,int,int,int);

void main()

{

int gd=DETECT,gm;

int xcenter,ycenter,rx,ry;

int p,x,y,px,py,rx1,ry1,rx2,ry2;

initgraph(&gd,&gm,"C:\\TC\\BGI"); /* request auto detect*/

printf("\n Enter the radius :"); /* get the radius and the center values*/

scanf("%d %d",&rx,&ry);

printf("\n Enter the xcenter and ycenter values :");

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

ry1=ry*ry;

rx1=rx*rx;

ry2=2*ry1;

rx2=2*rx1;

/* Region 1 */

x=0;

y=ry;


http://en.wikipedia.org/wiki/Circlehttp://en.wikipedia.org/wiki/Circle


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plotpoints(xcenter,ycenter,x,y); /* for the first region calculate the condition parameter*/

p=(ry1-rx1*ry+(0.25*rx1));

px=0;

py=rx2*y;printf("\nx\ty\tp\tpx\tpy\n");

printf("\n%d\t%d\t%d\t%d\t%d",x,y,p,px,py);

while(px=0)

{

y=y-1;

py=py-rx2;

p=p+ry1+px-py;

}

else

p=p+ry1+px;

plotpoints(xcenter,ycenter,x,y); /* call the plotpoints function*/


}

/* Region 2 */


printf("\n\nRegion 2\n");

printf("\nx\ty\tp\tpx\tpy\n"); /* for region 2 recalculate the condition variables*/

p=(ry1*(x+0.5)*(x+0.5)+rx1*(y-1)*(y-1)-rx1*ry1);

while(y>0)

{

y=y-1;

py=py-rx2;

if(p


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x=x+1;

px=px+ry2;

}

if(p>0)p=p+rx1-py;

else

p=p+rx1-py+px;

plotpoints(xcenter,ycenter,x,y); /* draw the pixels for region 2*/


}

getch();

closegraph();

}

void plotpoints(int xcenter,int ycenter,int x,int y) /* plot the points of the circle as per the procedure*/

{

putpixel(xcenter+x,ycenter+y,6);

putpixel(xcenter-x,ycenter+y,6);

putpixel(xcenter+x,ycenter-y,6);

putpixel(xcenter-x,ycenter-y,6);

}

OUTPUT:

Enter the radius:

1030

Enter the xcenter and ycenter values:310

155




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RESULT:

Thus the Midpoint Ellipse algorithm was successfully executed and the output is drawn and verified.




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IMPLEMENTATION OF TWO DIMENSIONAL TRANSFORMATIONS

DESCRIPTION:

A transformation is any operation on a point in space (x, y) that maps the point's coordinates into a newset of coordinates (x1, y1).The Two Dimensional transformations has five operations such as Translation,

Rotation, Reflection, Scaling and Shearing.

CODING:

#include

#include

#include#include

int x1,x2,x3,y1,y2,y3,t,tx,sx,sy,shx,shy,ch;

float rx1,rx2,rx3,ry1,ry2,ry3;float ang,theta;

int main(void)

{int gdriver = DETECT, gmode, errorcode;

initgraph(&gdriver, &gmode,"C:\\TC\\BGI"); /* request for auto detection*/errorcode = graphresult();

if(errorcode != grOk) /* if error occours*/{



exit(1);

}

else{

do{

printf("\n1.Translation\n2.Reflection\n3.Rotation\n4.Scaling\n5.Shearing\n");printf("\nEnter Your choice"); /* get the choice from the user*/scanf("%d",&ch);

switch(ch)

{case 1:

printf("\n Enter all coordinates values :"); /* get the coordinate values*/scanf("%d %d %d %d %d %d",&x1,&y1,&x2,&y2,&x3,&y3);printf("\n Before Translation ");

line(x1,y1,x2,y2);

line(x2,y2,x3,y3);line(x3,y3,x1,y1);

printf("\n Enter the value tranlsation factor :");




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scanf("%d",&tx); /* get the value for the translation factor*/printf("\n After Translation\n ");

line(x1+tx,y1,x2+tx,y2); /* draw the new translated image*/line(x2+tx,y2,x3+tx,y3);

line(x3+tx,y3,x1+tx,y1);

break;case 2:

printf("\n Enter all coordinates values :");

scanf("%d %d %d %d %d %d",&x1,&y1,&x2,&y2,&x3,&y3);printf("\n Before Reflection "); /* draw the image before reflection*/line(x1,y1,x2,y2);

line(x2,y2,x3,y3);

line(x3,y3,x1,y1);t=abs(y1-y3); /* find the value of the reflection factor*/printf("\n After Reflection ");

line(x1,y1+10+(2*t),x2,y2+10); /* draw the reflected object*/

line(x2,y2+10,x3,y3+10);line(x3,y3+10,x1,y1+10+(2*t));

break;

case 3:printf("\n Enter all coordinates values :");

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

printf("\n Before Rotation "); /* get the original coordinates*/line(x1,y1,x2,y2);

line(x2,y2,x3,y3);

line(x3,y3,x1,y1);

printf("\n Enter the rotation angle :"); /* get the angle for rotation*/

scanf("%f",&ang);theta=((ang*3.14)/180); /* convert the given angle*/rx1=x1*cos(theta)-y1*sin(theta);rx2=x2*cos(theta)-y2*sin(theta);

rx3=x3*cos(theta)-y3*sin(theta);

ry1=x1*sin(theta)+y1*cos(theta);

ry2=x2*sin(theta)+y2*cos(theta);ry3=x3*sin(theta)+y3*cos(theta);

printf("\n After Rotation "); /* draw the rotated image*/

line(rx1,ry1,rx2,ry2);

line(rx2,ry2,rx3,ry3);

line(rx3,ry3,rx1,ry1);break;

case 4:printf("\n Enter all coordinates values :");

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

printf("\n Before Scaling "); /* get the scale factor*/line(x1,y1,x2,y2);

line(x2,y2,x3,y3);

line(x3,y3,x1,y1);printf("\n Enter the Scale factor :");




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

printf("\n After Scaling "); /* draw the object after scaling*/

line(x1+sx,y1+sy,x2+sx,y2+sy);line(x2+sx,y2+sy,x3+sx,y3+sy);

line(x3+sx,y3+sy,x1+sx,y1+sy);

break;case 5:

printf("\n Enter all coordinates values :");

scanf("%d %d %d %d %d %d",&x1,&y1,&x2,&y2,&x3,&y3);printf("\n Before Shearing "); /* get the values for shearing*/line(x1,y1,x2,y2);

line(x2,y2,x3,y3);

line(x3,y3,x1,y1);printf("\n Enter 0 for x-axis and 1 for y-axis: ");

scanf("%d",&ch);

if(ch==0)

{printf("\n Enter the x-SHEAR (^.^) Value: ");

scanf("%d",&shx);

x1=x1+shx*y1;x2=x2+shx*y2;

x3=x3+shx*y3;

}else

{

printf("\n Enter the y-SHEAR (^.^) Value: ");

scanf("%d",&shy);

y1=y1+shy*x1;y2=y2+shy*x2;

y3=y3+shy*x3;}

printf("\n After Shearing ");

line(x1,y1,x2,y2); /* draw the final object after shearing*/

line(x2,y2,x3,y3);line(x3,y3,x1,y1);

break;

default:

exit(0);

break;}

}while(ch!=0);

}

getch();closegraph(); /* close the graph*/return 0;

}




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OUTPUT:

1. Translation2. Reflection3. Rotation4. Scaling5. ShearingEnter Your choice 1

Enter all coordinates values 213 236 253 321 256 214

Before Translation

Enter the value translation vector 32

After Translation






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Before

After Reflection



Before Rotation

Enter the rotation angle 20

After Rotation




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Before Scaling

Enter the scale factor 10 5

After Scaling



Before Shearing

Enter 0 for x axis and 1 for y axis 0




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Enter the x-shear value 1

After Shearing

Before Shearing


Enter the y-shear value 1

RESULT:

Thus the Two dimensional transformations were successfully executed and the output is transformed,

drawn and verified.




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IMPLEMENTATION OF TWO DIMENSIONAL COMPOSITE TRANSFORMATIONS

DESCRIPTION:

A transformation is any operation on a point in space (x, y) that maps the point's coordinates into a newset of coordinates (x1, y1).The Two Dimensional Composite transformation represent a sequence of

transformations as a single matrix which has the order of operations as Translation, Rotation, Scaling, Shearing,

Reflection.

CODING:


#include

#include

#include

#include

int xa,xb,xc,ya,yb,yc,y1a,y1b,y1c,x1a,x1b,x1c,x2a,x2b,x2c,y2a,y2b,y2c;

int x3a,x3b,x3c,y3a,y3b,y3c,x4a,x4b,x4c,y4a,y4b,y4c,x5a,x5b,x5c,y5a,y5b,y5c;

int tx,shx,t,ch,shy;

float ang,theta,sx,sy;

int main(void)

{

int gdriver = DETECT, gmode, errorcode;

initgraph(&gdriver, &gmode,"C:\\TC\\BGI"); /* request for auto detection*/

printf("\n\t\t\t 2D Composite Transformations");

printf("\n\n Enter all coordinates values :");

scanf("%d %d %d %d %d %d",&xa,&ya,&xb,&yb,&xc,&yc);

printf("\n\n The original Image"); /* get the coordinates for the original image*/

line(xa,ya,xb,yb); /* draw the original image*/

line(xb,yb,xc,yc);

line(xc,yc,xa,ya);

printf("\n\n Enter the value tranlsation factor :"); /* get the translation factor*/

scanf("%d",&tx);




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printf("\n\n After Translation ");

x1a=xa+tx;

x1b=xb+tx;

x1c=xc+tx;y1a=ya;

y1b=yb;

y1c=yc;

line(x1a,y1a,x1b,y1b); /* image after translation*/

line(x1b,y1b,x1c,y1c);

line(x1c,y1c,x1a,y1a);

delay(1);

printf("\n\n Next Operation is Rotation");

printf("\n\n Enter the rotation angle :"); /* get the angle of rotation*/

scanf("%f",&ang);

theta=((ang*3.14)/180); /* convert the angle*/

x2a=x1a*cos(theta)-y1a*sin(theta);

y2a=x1a*sin(theta)+y1a*cos(theta);

x2b=x1b*cos(theta)-y1b*sin(theta);

y2b=x1b*sin(theta)+y1b*cos(theta);

x2c=x1c*cos(theta)-y1c*sin(theta);

y2c=x1c*sin(theta)+y1c*cos(theta);

printf("\n\n After Rotation "); /* the rotated object*/

line(x2a,y2a,x2b,y2b);



delay(1);

printf("\n\n Next Operation is Scaling"); /* get the scale factor*/

printf("\n\n Enter the Scale factor :");

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

x3a=x2a+sx; /* modify the objects coordinates based on the scale factor*/

y3a=y2a+sy;

x3b=x2b+sx;




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y3b=y2b+sy;

x3c=x2c+sx;

y3c=y2c+sy;

printf("\n\n After Scaling ");line(x3a,y3a,x3b,y3b);



delay(1);

printf("\n\n Next Operation is Shearing");

printf("\n\n Enter 1 for x-axis \n 2 for y-axis: "); /* get the choice of shearing in the x or y axis*/

scanf("%d",&ch);

if(ch==1) /* get the shear value*/

{

printf("\n\n Enter the x-SHEAR (^.^) Value: ");

scanf("%d",&shx);

}

else

{

printf("\n\n Enter the y-SHEAR (^.^) Value: ");

scanf("%d",&shy);

}

if(ch==1)

{

x3a=x3a+shx*y3a;

y4a=y3a;

x3b=x3a+shx*y3a;

y4b=y3b;

x3c=x3a+shx*y3a;

y4c=y3c;

}

else

{




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x4a=x3a;

y3a=y3a+shy*x3a;

x4b=x3b;

y3b=y3b+shy*x3b;x4c=x3c;

y3c=y3c+shy*x3c;

}

printf("\n\n After Shearing "); /* draw the final object after shearing*/




delay(1);

printf("\n\n Next Operation is Reflection");

t=abs(y3a-y3c); /* calculate the value for reflection*/

x5a=x3a;

x5b=x3b;

x5c=x3c;

y5a=y3a+10+(2*t);

y5b=y3b+10;

y5c=y3c+10;

printf("\n\n After Reflection "); /* the final object after all the transformations*/




getch();

closegraph();

return 0;

}




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OUTPUT:

2D Composite Transformations


The original Image

Enter the value translation vector 32

After Translation

Next Operation is Rotation

Enter the rotation angle 20

After Rotation

Next Operation is Scaling

Enter the scale factor 10 5




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After Scaling

Next Operation is Shearing


Enter the x-shear value 1

After Shearing


Enter the y-shear value 1

Next Operation is Reflection

After Reflection




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RESULT:

Thus the Two dimensional Composite transformations were successfully executed and the output is

transformed, drawn and verified.




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IMPLEMENTATION OF LINE, CIRCLE AND ELLIPSE ATTRIBUTES

DESCRIPTION:

Output primitives have geometric and non-geometric attributes. Geometric attributes, such as thecharacter height, affect the size and shape of a primitive, whereas non-geometric attributes are qualities such as

colour, line style, etc. The output primitives Such as Line, Circle and Ellipse are associated with set of attributes

such as Line (color and Line Style), Cicrle (Color) and Ellipse (Color and Patterns).

CODING:


#include

#include

#include

int main(void)

{

/* select a driver and mode that supports */

/* multiple drawing colors.*/

int gdriver=EGA,DETECT,gmode=EGAHI,errorcode;

int color,maxcolor,x,y,s,ch,ch1,ch2,i;

int midx,midy;

int radius=100;

int xradius=100,yradius=50;

char msg[80];

char *lname[]={"Solid Line", "Dotted Line", "Center Line", "Dashed Line", "Usebit Line"};

/* initialize graphics and local variables */

initgraph(&gdriver,&gmode,"c:\\tc\\bgi");

/* read result of initialization */

errorcode=graphresult();

if (errorcode!=grOk) /* an error occurred */

{





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printf("Press any key to halt:");

getch();

exit(1); /* terminate with an error code */

}do{

printf("\n1.Line\n2.Circle\n3.Ellipse\n"); /* get the user choice*/

printf("\nEnter Your choice\n");

scanf("%d",&ch);

switch(ch)

{

case 1:

printf("Attribute: 1.Color 2.Style:\n");

scanf("%d",&ch1);

switch(ch1)

{

case 1:

maxcolor=getmaxcolor(); /* use predefined methods to change the color*/

x=getmaxx()/2;

y=getmaxy()/2;

for(color=1;color


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for(s=0;s


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{

case 1:

/* initialize graphics and local variables */

initgraph(&gdriver,&gmode,"c:\\tc\\bgi");midx=getmaxx()/2;

midy=getmaxy()/2;

/* loop through the fill patterns */

for(i=EMPTY_FILL;i


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//exit(0);

break;

}

}while(ch==3);

return 0;

}

OUTPUT:

Line Color

Line Style




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Circle Color

Ellipse Pattern

Ellipse Color




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RESULT:

Thus the attributes were successfully applied to Line, circle and ellipse and the output is drawn and

verified.




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IMPLEMENTATION OF COHEN SUTHERLAND LINE CLIPPING ALGORITHM

DESCRIPTION:

The Cohen Sutherland Algorithm is a line clipping algorithm which quickly detects and dispenseswith two common and trivial cases. To clip a line, we need to consider only its endpoints. If both endpoints of a

line lie inside the window, the entire line lies inside the window. It is trivially accepted and needs no clipping.

On the other hand, if both endpoints of a line lie entirely to one side of the window, the line must lie entirely

outside of the window. It is trivially rejected and needs to be neither clipped nor displayed.

CODING:


#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); /* initialize the values*/

code1=calcode(x1,y1,xwmin,ywmin,xwmax,ywmax);

do

{

if(!(code0|code1)) /*vary the condition variables value based on the values*/

{

accept=1;done=1;

}

else

if(code0&code1)done=1;


http://en.wikipedia.org/wiki/Line_clippinghttp://www.cs.helsinki.fi/group/goa/viewing/leikkaus/trivial.htmlhttp://www.cs.helsinki.fi/group/goa/viewing/leikkaus/trivial.htmlhttp://www.cs.helsinki.fi/group/goa/viewing/leikkaus/trivial.htmlhttp://www.cs.helsinki.fi/group/goa/viewing/leikkaus/trivial.htmlhttp://en.wikipedia.org/wiki/Line_clipping


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else

{

float x,y;

codeout=code0?code0:code1;if(codeout&TOP) /* now, decide the position of the object on the clipping window*/

{

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;


}

else




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{

x1=x;y1=y;


}}

}

while(done==0);

if(accept)

line(x0,y0,x1,y1);

rectangle(xwmin,ywmin,xwmax,ywmax); /* draw the clipping window*/

getch();

}

int calcode(x,y,xwmin,ywmin,xwmax,ywmax)

float x,y,xwmin,ywmin,xwmax,ywmax;

{

int code=0; /* assign the values of the clipped image*/

if(y>ywmax)

code|=TOP;

else if(yxwmax)

code|=RIGHT;

else if (x


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printf("\n\n\tEnter the co-ordinates of Line :"); /* get the coordinates of the 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 "); /* get the coordinates of the clipping window*/

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 );/* call the clipping function*/

getch();

closegraph();

}

OUTPUT:

X1, Y1 =120 240

X2, Y2 =350 500

Xwmin, Ywmin= 200 200

Xwmax, Ywmax= 350 350




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Before Clipping

After Clipping

RESULT:

Thus the Cohen Sutherland line clipping algorithm was successfully executed and the output is drawn

and verified.




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IMPLEMENTATION OF SUTHERLAND HODGEMAN POLYGON CLIPPING ALGORITHM

DESCRIPTION:

The Sutherland Hodgeman Algorithm is used forclipping polygons. It works by extending each lineof the convex clip polygon in turn and selecting only vertices from the subject polygon that is on the visible

side. This algorithm performs a clipping of a polygon against each window edge in turn. It accepts an ordered

sequence of vertices v1, v2, v3... vn and puts out a set of vertices defining the clipped polygon.

CODING:


#include

#include

#include

#include

#define TRUE 1

#define FALSE 0

typedef unsigned int outcode;

outcode CompOutCode(float x,float y); /* create an user defined function for the output*/

enum

{

TOP=0x1,

BOTTOM=0x2,

RIGHT=0x4,

LEFT=0x8

};

float xmin,xmax,ymin,ymax;

void clip(float x0,float y0,float x1,float y1) /* define the clipping function*/

{

outcode outcode0,outcode1,outcodeOut;

int accept=FALSE,done=FALSE;

outcode0=CompOutCode(x0,y0); /* call the user defined function*/


http://en.wikipedia.org/wiki/Clipping_%28computer_graphics%29http://en.wikipedia.org/wiki/Polygonhttp://en.wikipedia.org/wiki/Convex_polygonhttp://en.wikipedia.org/wiki/Convex_polygonhttp://en.wikipedia.org/wiki/Polygonhttp://en.wikipedia.org/wiki/Clipping_%28computer_graphics%29


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outcode1=CompOutCode(x1,y1);

do /* assign the values for the condition variables*/

{

if(!(outcode0|outcode1)){

accept=TRUE;

done=TRUE;

}

else

if(outcode0&outcode1)

done=TRUE;

else

{

float x,y;

outcodeOut=outcode0?outcode0:outcode1; /* use the tertiary operator to assign values*/

if(outcodeOut&TOP) /* reassign the value of x and y */

{

x=x0+(x1-x0)*(ymax-y0)/(y1-y0);

y=ymax;

}

else

if(outcodeOut&BOTTOM)

{

x=x0+(x1-x0)*(ymin-y0)/(y1-y0);

y=ymin;

}

else

if(outcodeOut&RIGHT)

{

y=y0+(y1-y0)*(xmax-x0)/(x1-x0);

x=xmax;

}




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else

{

y=y0+(y1-y0)*(xmin-x0)/(x1-x0);

x=xmin;}

if(outcodeOut==outcode0)

{

x0=x;

y0=y;


}

else

{

x1=x;

y1=y;


}

}

}

while(done==FALSE);

if(accept)

line(x0,y0,x1,y1);

outtextxy(150,20,"POLYGON AFTER CLIPPING");

rectangle(xmin,ymin,xmax,ymax); /* draw the clipping window*/

}

outcode CompOutCode(float x,float y) /* define the output function*/

{

outcode code=0;

if(y>ymax)

code|=TOP;

else

if(y


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code|=BOTTOM;

if(x>xmax)

code|=RIGHT;

elseif(x


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for(i=0;i


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RESULT:

Thus the Sutherland Hodgeman polygon clipping algorithm was successfully executed and the output is

drawn and verified.




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OPEN GL PROGRAMS USING VC++

PROCEDURE:

Before executing the programs you have to place three header files (dll, Header, Lib) in the followinglocations

Header:

C:\Program Files\Microsoft Visual Studio\VC98\Include\GL

Lib:

C:\Program Files\Microsoft Visual Studio\VC98\Lib

Dll:

C:\WINDOWS\system32

Go to StartProgramsMicrosoft Visual Studio 6.0Microsoft Visual C++ 6.0 FileNew...

New dialog boxes opens in that select the win32console application from the projects tab and give thename for the project and click on the ok and finish button.




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Now select Tools menu and select options from it.

In that select the directories tab and select the browse button as given in the below screenshot.

Select the path for the three header files that you have pasted in different locations and click on the okbutton.




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FileNew...

Select the C++ source file from the files tab and give the name for the file and click ok button .

Now select project menu and select the settings from the drop down menu.




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In the project settings dialog box click on the link tab and type the three file names at the end of theobject/library modules text box.

File names: opengl32.lib glu32.lib glut32.lib

After entering the file names click on the C/C++ tab and select C++ Language from the category dropdown list and click on the ok button




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After performing these steps type the required program code save the program and click on the buildbutton.

Then click on the Execute program button




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IMPLEMENTATION OF 3D OBJECTS MENU USING IN VC++ USING OPENGL

DESCRIPTION:

CODING:

#include

#include

#include

#include

static GLfloat rot=0,a=1.0,b=1.0,c=1.0,as,tx,tz,sx,sy,sz,rx,ry,rz,an,ang;

static GLint op,p,pr,pd,ch,key;

void disp()

{

glClear(GL_COLOR_BUFFER_BIT);

glMatrixMode(GL_PROJECTION);

glLoadIdentity();

gluPerspective(80.0,(GLdouble)4/(GLdouble)3,0.1,30.0);

glMatrixMode(GL_MODELVIEW);

glLoadIdentity();

gluLookAt(0.0,0.0,20.0,0.0,0.0,0.0,0.0,1.0,1.0);

if(pr==1)

{

glColor3f(1.0,1.0,0.0);

glutWireTeapot(8);

}

if(pr==2)

{

glColor3f(0.0,1.0,1.0);

glutWireSphere(12,20,40);

}

if(pr==3)




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{

glColor3f(1.0,0.0,1.0);

glutWireTorus(4,8,20,40);

}if(pr==4)

{

glColor3f(1.0,1.0,0.0);

glutWireCube(8);

}

if(pr==5)

{

glColor3f(1.0,0.0,0.0);

glutWireCone(3.0,3.0,10,20);

}

if(pr==6)

{

glColor3f(1.0,0.0,1.0);

glutWireTetrahedron();

}

if(pr==7)

{

glColor3f(1.0,0.0,1.0);

glutWireOctahedron();

}

glutSwapBuffers();

}

void myidle()

{

rot=rot+1.0;

glutPostRedisplay();

}

void mykey(unsigned char pd,int x,int y)




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{

switch(pd)

{

case 'p':printf("1.Teapot \n2.Sphere \n3.Torus \n4.Cube \n5.Cone \n6.Tetrahedron

\n7.Octahedron");

printf("\nEnter the option");

scanf("%d",&p);

switch(p)

{

case 1:pr=1;

break;

case 2:pr=2;

break;

case 3:pr=3;

break;

case 4:pr=4;

break;

case 5:pr=5;

break;

case 6:pr=6;

break;

case 7:pr=7;

break;

}

break;

}

}

void main(int argc,char** argv)

{

glutInit(&argc,argv);

glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGB);




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glutInitWindowSize(640,480);

glutInitWindowPosition(0,0);

glutCreateWindow("3d program");

glClearColor(0,0,0,0);glutDisplayFunc(disp);

glutKeyboardFunc(mykey);

glutIdleFunc(myidle);

glutMainLoop();

}

OUTPUT:




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IMPLEMENTATION OF 3D COMPOSITE TRANSFORMATION IN VC++ USING OPENGL

DESCRIPTION:

CODING:

#include

#include

#include

#include

static GLfloat rot=0,a=1.0,b=1.0,c=1.0,as,tx,ty,tz,sx,sy,sz,rx,ry,rz,an,ang;

static GLint op,p,pr,pd,ch,key;

void mydisp()

{

glClear(GL_COLOR_BUFFER_BIT);

glMatrixMode(GL_PROJECTION);

glLoadIdentity();

gluPerspective(80.0,(GLdouble)4/(GLdouble)3,0.1,30.0);

glMatrixMode(GL_MODELVIEW);

glLoadIdentity();

gluLookAt(0.0,0.0,20.0,0.0,0.0,0.0,0.0,1.0,1.0);

if(as==1)

glTranslatef(a,b,c);

if(as==2)

glScalef(a,b,c);

if(as==3)

glRotatef(an,a,b,c);

if(pr==1)

{

glColor3f(1.0,1.0,0.0);

glutWireTeapot(8);




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}

if(pr==2)

{

glColor3f(0.0,1.0,1.0);glutWireSphere(12,20,40);

}

if(pr==3)

{

glColor3f(1.0,0.0,1.0);

glutWireTorus(4,8,20,40);

}

if(pr==4)

{

glColor3f(1.0,1.0,0.0);

glutWireCube(8);

}

if(pr==5)

{

glColor3f(1.0,0.0,0.0);

glutWireCone(3.0,3.0,10,20);

}

if(pr==6)

{

glColor3f(1.0,0.0,1.0);

glutWireTetrahedron();

}

if(pr==7)

{

glColor3f(1.0,0.0,1.0);

glutWireOctahedron();

}

glutSwapBuffers();




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}

void myidle()

{

rot=rot+1.0;glutPostRedisplay();

}

void myKey(unsigned char pd,int x,int y)

{

switch(pd)

{

case 'p':

case 'P':

printf("1.teapot\n2.sphere\n3.torus\n4.cube\n5.cone\n6.tetrahedron\n7.octahedron");

printf("\nEnter the option");

scanf("%d",&p);

switch(p)

{

case 1:

pr=1;

break;

case 2:

pr=2;

break;

case 3:

pr=3;

break;

case 4:

pr=4;

break;

case 5:

pr=5;

break;




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case 6:

pr=6;

break;

case 7:pr=7;

break;

}

break;

case 'm':

case'M':

glColor3f(1.0,1.0,0.0);

glutWireTeapot(8);

printf("1.translation \n 2.scaling \n3.rotation");

printf("\n Enter the option");

scanf("%d",&op);

switch(op)

{

case 1:

printf("Enter the tx,ty,tz values");

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

a=(GLfloat)tx;

b=(GLfloat)ty;

c=(GLfloat)tz;

as=1;

break;

case 2:

printf("Enter the sx,sy,sz values");

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

a=(GLfloat)sx;

b=(GLfloat)sy;




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c=(GLfloat)sz;

as=2;

break;

case 3:

printf("Enter the rx,ry,rz values");

scanf("%f %f %f",&rx,&ry,&rz);

a=(GLfloat)rx;

b=(GLfloat)ry;

c=(GLfloat)rz;

as=3;

break;

default:

printf("choose the correct option");

break;

}

}

}

void main(int argc,char** argv)

{

glutInit(&argc,argv);

glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGB);

glutInitWindowSize(640,480);

glutInitWindowPosition(0,0);

glutCreateWindow("3D PROGRAM");

glClearColor(0,0,0,0);

glutDisplayFunc(mydisp);

glutKeyboardFunc(myKey);

glutIdleFunc(myidle);

glutMainLoop();

}




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OUTPUT:

BEFORE TRANSFORMATION:




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AFTER TRANSLATION:




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AFTER SCALING:




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AFTER ROATAION:




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BEFORE TRANSFORMATION:

AFTER TRANSLATION:




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AFTER SCALING:




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AFTER ROATAION:




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cs computer graphics lab manual

Documents