Program 3: Write a program to implement 2D Geometric Transformations.

PROGRAM 3: 2D transformations

·         Header File

·         Render func

·         Handle resize

·         Display

·         Timer

·         Main func

1.      Header File.(gl/glut.h , math.h, windows.h)

2.      Initialise rendering function for the 2d object

void initRendering()

{         

glEnable(GL_DEPTH_TEST);

}

3.      Create Handle Resize

void handleResize(int w,int h)

{

glViewport(0,0,w,h);

glMatrixMode(GL_PROJECTION);

glLoadIdentity();

gluPerspective(45.0,(double)w/(double)h,1.0,200.0);

}

4.      Display Function

void drawScene()

{

    glClearColor(0.0f, 0.0f, 1.0f, 0.0f);//dark blue

    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);

    glMatrixMode(GL_MODELVIEW);

    glLoadIdentity();

    glRotatef(_angle,0.0f,0.0f,1.0f); //rotate object by 30 degree with respect to y-axis

    glTranslatef(0.0f, 0.0f, -10.0f);

    //************************

    glPushMatrix();

    glScalef(2,2,2);

    //OBJ

      glPopMatrix();

    glutSwapBuffers();

}

5.      Timer

void update(int value)

{

       _angle+=2.0f;

      if(_angle>360.f)

      {

                  _angle-=360;

      }

    glutPostRedisplay();

    glutTimerFunc(25,update,0);

}

6.      Main Function

int main(int argc,char**argv)

{

    glutInit(&argc,argv);

    glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGB|GLUT_DEPTH);

    glutInitWindowSize(600,600);

    glutCreateWindow("rotate");

    initRendering();

    glutDisplayFunc(drawScene);

    glutReshapeFunc(handleResize);

    glutTimerFunc(25,update,0);

    glutMainLoop();

    return 0;

}

SAMPLE PROGRAM:PROGRAM 3

//header file and include math.h as well

#include<math.h>

float _angle=45.0;

void initRendering()

{

glEnable(GL_DEPTH_TEST);

}

void handleResize(int w,int h)

{

glViewport(0,0,w,h);

glMatrixMode(GL_PROJECTION);

glLoadIdentity();

gluPerspective(45.0,(double)w/(double)h,1.0,200.0);

}

void drawScene()

{

    glClearColor(0.0f, 0.0f, 1.0f, 0.0f);//dark blue

    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);

    glMatrixMode(GL_MODELVIEW);

    glLoadIdentity();

    glRotatef(_angle,0.0f,0.0f,1.0f); //rotate object by 30 degree with respect to y-axis

    glTranslatef(0.0f, 0.0f, -10.0f);

    //************************

    glPushMatrix();

    glScalef(2,2,2);

    //OBJ

    glPopMatrix();

    glutSwapBuffers();

}

void update(int value)

{

    _angle+=2.0f;

    if(_angle>360.f)

    {

    _angle-=360;

    }

    glutPostRedisplay();

    glutTimerFunc(25,update,0);

}

int main(int argc,char**argv)

{

    glutInit(&argc,argv);

    glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGB|GLUT_DEPTH);

    glutInitWindowSize(600,600);

    glutCreateWindow("rotate");

    initRendering();

    glutDisplayFunc(drawScene);

    glutReshapeFunc(handleResize);

    glutTimerFunc(25,update,0);

    glutMainLoop();

    return 0;

}