[IFET PLACEMENT] Computer Graphics 3rd Lab exercise
- From: Prasanna Venkadesh <prasmailme@xxxxxxxxx>
- To: compass@xxxxxxxxxxxxx
- Date: Tue, 9 Aug 2011 20:02:50 +0530
Hi friends,
Here i have attached the program for 3rd lab exercise in Computer graphics.
Dont forget to check.
--
Regards,
Prasanna Venkadesh
----------------------------------------------------------------------------
PuduvaiLUG (puduvai Linux Users Group): http://puduvailug.wordpress.com/
FOSS Jobs all over India: http://fossjobs.in
#include <math.h>
#include <GL/glut.h>
#include <stdio.h>
//#include <stdlib.h>
typedef float Matrix3x3 [3][3];
Matrix3x3 theMatrix;
int NEdges;
float ptsIni[20][2];
float ptsFin[20][2];
float refpt[2];
float RotAngle;
float TransDistX,TransDistY;
float ScaleX,ScaleY;
int choice,choiceRef,choiceShear;
float slope,yIntercept;
float shearValue;
void matrixSetIdentity(Matrix3x3 m)
{
int i, j;
for (i=0; i<3; i++)
for (j=0; j<3; j++)
m[i][j] = (i == j);
}
void matrixPreMultiply(Matrix3x3 a , Matrix3x3 b)
// Multiplies matrix a times b, putting result in b
{
int i,j;
Matrix3x3 tmp;
for (i = 0; i < 3; i++)
for (j = 0; j < 3; j++)
tmp[i][j] = a[i][0]*b[0][j] + a[i][1]*b[1][j] + a[i][2]*b[2][j];
for (i = 0; i < 3; i++)
for (j = 0; j < 3; j++)
theMatrix[i][j] = tmp[i][j];
}
void Translate(int tx, int ty)
{
Matrix3x3 m;
matrixSetIdentity(m);
m[0][2] = tx;
m[1][2] = ty;
matrixPreMultiply(m, theMatrix);
}
void Scale(float sx , float sy)
{
Matrix3x3 m;
matrixSetIdentity(m);
m[0][0] = sx;
m[0][2] = (1 - sx)*refpt[0];
m[1][1] = sy;
m[1][2] = (1 - sy)*refpt[1];
matrixPreMultiply(m , theMatrix);
}
void Rotate(float a)
{
Matrix3x3 m;
matrixSetIdentity(m);
a = a*22/1260;
m[0][0] = cos(a);
m[0][1] = -sin(a) ;
m[0][2] = refpt[0]*(1 - cos(a)) + refpt[1]*sin(a);
m[1][0] = sin(a);
m[1][1] = cos(a);
m[1][2] = refpt[1]*(1 - cos(a)) - refpt[0]*sin(a);
matrixPreMultiply(m , theMatrix);
}
void Reflect(int xy)
{
Matrix3x3 m;
matrixSetIdentity(m);
if(xy == 2)
m[1][1] = -1;
if(xy == 3)
m[0][0] = -1;
matrixPreMultiply(m , theMatrix);
}
void Shear(int xy)
{
Matrix3x3 m;
matrixSetIdentity(m);
if(xy == 1)
m[0][1] = shearValue;
if(xy == 2)
m[1][0] = shearValue;
matrixPreMultiply(m , theMatrix);
}
void TransformPoints(void)
{
int k;
float tmp ;
for (k = 0 ; k<NEdges && k<20 ; k++)
{
ptsFin[k][0] = theMatrix[0][0]*ptsIni[k][0]+ theMatrix[0][1]*ptsIni[k][1] +
theMatrix[0][2];
ptsFin[k][1] = theMatrix[1][0]*ptsIni[k][0]+ theMatrix[1][1]*ptsIni[k][1] +
theMatrix[1][2];
}
}
void display(void)
{
glClear (GL_COLOR_BUFFER_BIT);
glColor3f (0.0, 0.0, 0.0);
glBegin(GL_LINES);
glVertex2s(-1000 ,0);
glVertex2s( 1000 ,0);
glEnd();
glBegin(GL_LINES);
glVertex2s(0 ,-1000);
glVertex2s(0 , 1000);
glEnd();
glColor3f (1.0, 0.0, 0.0);
int PlotCt;
glBegin(GL_POLYGON);
for(PlotCt=0 ; PlotCt<NEdges ; PlotCt++)
{
glVertex2s(ptsIni[PlotCt][0],ptsIni[PlotCt][1]);
}
glEnd();
matrixSetIdentity(theMatrix);
switch(choice)
{
case 1:
Translate(TransDistX , TransDistY);
break;
case 2:
Rotate(RotAngle);
break;
case 3:
Scale(ScaleX, ScaleY);
break;
case 4: switch(choiceRef)
{
case 1 :
refpt[0]=0.0; refpt[1]=0.0;
Rotate(180);
break;
case 2 :
Reflect(2);
break;
case 3 :
Reflect(3);
break;
case 4 :
Translate(slope/yIntercept , -yIntercept);
Rotate(-1260*atan(slope)/22);
Reflect(2);
Rotate(1260*atan(slope)/22);
Translate(-slope/yIntercept , yIntercept);
glBegin(GL_LINES);
glVertex2s(-1000 ,-slope*1000 + yIntercept);
glVertex2s( 1000 , slope*1000 + yIntercept);
glEnd();
break;
}
case 5:
Shear(choiceShear);
break;
}
TransformPoints();
glColor3f (0.0, 1.0, 0.0);
glBegin(GL_POLYGON);
for(PlotCt=0 ; PlotCt<NEdges ; PlotCt++)
{
glVertex2s(ptsFin[PlotCt][0],ptsFin[PlotCt][1]);
}
glEnd();
glFlush();
}
void init(void)
{
glClearColor (1.0, 1.0, 1.0, 1.0);
// Set the Background color to WHITE
glOrtho(-200.0, 200.0, -200.0, 200.0, -1.0, 1.0);
// Set the no. of Co-ordinates along X & Y axes and their gappings
}
int main (int argc, char *argv)
{
glutInit(&argc, &argv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
glutInitWindowSize (750, 750);
glutInitWindowPosition (0, 0);
glutCreateWindow (" Basic Transformations ");
init ();
printf("Enter the no. of Vertices of polygon:\n=> ");
scanf("%d",&NEdges);
printf("Enter %d Co-ordinate pairs \n",NEdges);
int PlotCt;
for(PlotCt=0 ; PlotCt<NEdges ; PlotCt++)
scanf("%f %f",&ptsIni[PlotCt][0],&ptsIni[PlotCt][1]);
printf("Enter your choice
number:\n1.Translation\n2.Rotation\n3.Scaling\n4.Reflection\n5.Shearing\n=>");
scanf("%d",&choice);
switch(choice)
{
case 1:
printf("Enter translation along X & Y\n=>");
scanf("%f%f",&TransDistX , &TransDistY);
break;
case 2:
printf("Enter Angle of Rotation\n=>");
scanf("%f",&RotAngle);
printf("Enter reference point Co-ordinates:\n=>");
scanf("%f %f",&refpt[0],&refpt[1]);
break;
case 3:
printf("Enter Scaling ratios along X & Y\n=>");
scanf("%f%f",&ScaleX , &ScaleY);
break;
case 4:
printf("Enter your choice number for Reflection about: \n 1.Origin\n
2.X-axis\n 3.Y-axis\n 4.y = mx+c\n=>");
scanf("%d",&choiceRef);
if(choiceRef == 4)
{
printf("Enter m & c: \n=>");
scanf("%f %f",&slope,&yIntercept);
}
break;
case 5:
printf("Enter your choice number to shear about: \n 1.x-axis\n
2.y-axis\n=>");
scanf("%d",&choiceShear);
printf("Enter shear value:\n=>");
scanf("%f",&shearValue);
break;
default:
printf("Wrong Key\n");
return 0;
}
glutDisplayFunc(display);
glutMainLoop();
return 0;
}
Other related posts:
- » [IFET PLACEMENT] Computer Graphics 3rd Lab exercise - Prasanna Venkadesh
