A simple OpenGL line Animation

Hi all  , today I like to share some code example about a opengl animation with you.

#include <stdio.h>
#include <stdlib.h>

#include <GL/gl.h>
#include <GL/glut.h>

static double s_line_length = 0.5;

void display_function(void)
{
 glClear(GL_COLOR_BUFFER_BIT);
 glColor3f(0.0 ,1.0,0.0);
 glBegin (GL_LINES);
 glVertex3f (0.0 ,s_line_length , 0.0);
 glVertex3f (s_line_length, 0.0 ,0.0);
 glColor3f(0.0,0.0,1.0);
 glVertex3f( 0.0 , -s_line_length , 0.0);
 glVertex3f(-s_line_length , 0.0 , 0.0);

 glEnd();
 glFlush();
}

void keyboard_function( unsigned char ch , int x , int y)
{
//    exit (0);

}

void timer_function( int value)
{
 static bool flag = true ;
 static int count = 5;
 if ( count == 10 )
 {
 flag=false;
 }
 if (count == 0){
 flag=true;
 }

 if (flag )
 {
 s_line_length += 0.1;
 count++;
 }
 else
 {
 s_line_length -= 0.1;
 count--;
 }
 glutPostRedisplay();
 glutTimerFunc( 200,timer_function , 0);
}

void mouse_func ( int button , int status , int x , int y)
{

}

int main ( int argc , char ** argv)
{
 glutInit( &argc , argv);
 glutInitDisplayMode(GLUT_SINGLE |GLUT_RGB);
 glutInitWindowSize( 250,250);
 glutInitWindowPosition(100,100);
 glutCreateWindow("Line Animation");
 glutKeyboardFunc( keyboard_function);
 glutDisplayFunc ( display_function);
 glutTimerFunc (1, timer_function,0);
 glutMouseFunc( mouse_func);

 glutMainLoop();
}

and to compile this , Just hit these commands.

$gcc -o ch04 ch04.cc -lglut -g

Assuming that you had already installed the GNU “C” compiler and you type and saved the source file as ch04.cc in your source code directory.

And here’s how it’s running , BINGO !

Oky let’s enjoy this in the windows plactform.

in the windows you need that dirty #define GLUT_DISABLE_ATEXIT_HACK ,

and I saved the library files from glut and opengl unzipped to C:\mingw\lib

those files named as GLUT32.lib and OPENGL32.lib and you should save the

GLUT32.dll file to your source directory.

#include <stdio.h>
#include <stdlib.h>
#define GLUT_DISABLE_ATEXIT_HACK

#include <GL/gl.h>
#include <GL/glut.h>


static double s_line_length = 0.5;


void display_function(void)
{
 glClear(GL_COLOR_BUFFER_BIT);
 glColor3f(0.0 ,1.0,0.0);
 glBegin (GL_LINES);
 glVertex3f (0.0 ,s_line_length , 0.0);
 glVertex3f (s_line_length, 0.0 ,0.0);
 glColor3f(0.0,0.0,1.0);
 glVertex3f( 0.0 , -s_line_length , 0.0);
 glVertex3f(-s_line_length , 0.0 , 0.0);

 glEnd();
 glFlush();
}

void keyboard_function( unsigned char ch , int x , int y)
{
 exit (0);


}

void timer_function( int value)
{
 static bool flag = true ;
 static int count = 5;
 if ( count == 10 )
 {
 flag=false;
 }
 if (count == 0){
 flag=true;
 }

 if (flag )
 {
 s_line_length += 0.1;
 count++;
 }
 else
 {
 s_line_length -= 0.1;
 count--;
 }
 glutPostRedisplay();
 glutTimerFunc( 200,timer_function , 0);
}

void mouse_func ( int button , int status , int x , int y)
{


}

int main ( int argc , char ** argv)
{


 glutInit( &argc , argv);
 glutInitDisplayMode(GLUT_SINGLE |GLUT_RGB);
 glutInitWindowSize( 250,250);
 glutInitWindowPosition(100,100);
 glutCreateWindow("Line Animation -Press any key to Exit");
 glutKeyboardFunc( keyboard_function);
 glutDisplayFunc ( display_function);
 glutTimerFunc (1, timer_function,0);
 glutMouseFunc( mouse_func);

 glutMainLoop();
}

And to compile it and run,

J:\EXERCISES\opengl\glut\ch04>gcc -o ch04.exe ch04_.cc -mwindows -lGLUT32 -lOPEN
GL32

J:\EXERCISES\opengl\glut\ch04> ch04.exe

Here you can download the sources and executables,

http://rapidshare.com/files/364072990/ch04.zip.html

–Enjoy And Happy Coding–