Mouse & keyboard .. switch

#include <iostream>
#include <glut.h>

GLint  WindowHeight = 400;
GLint  WindowWidth  = 400;

//-------------------------------------------------------------------
void myInit(void)
{
glClearColor(0.0, 0.0, 1.0, 0.0); // set the background to blue
glColor3f(1.0f, 1.0f, 1.0f);      // set the drawing color to white
glPointSize(4.0);

glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluOrtho2D(0.0,(float) WindowWidth,0.0, (float) WindowHeight);
}
//-------------------------------------------------------------------
void myDisplay(void)
{
  glClear( GL_COLOR_BUFFER_BIT );
  glFlush();
}
//-------------------------------------------------------------------
void draw(int x, int y)
{
glBegin(GL_POINTS);
glVertex2i(x, y);
glEnd();
 
glFlush();
}
//-------------------------------------------------------------------
void myMouse(int button, int state, int x, int y)
{

if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN)
{
draw(x, WindowHeight-y);
}

}
void processNormalKeys(unsigned char key, int x, int y){

if (key=='q')
exit(0);

}
//-------------------------------------------------------------------
void main( int argc, char **argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB );
glutInitWindowSize(WindowWidth,WindowHeight);
glutInitWindowPosition(0,0);
glutCreateWindow("Mouse Input");

glutDisplayFunc(myDisplay);
glutMouseFunc(myMouse);
glutKeyboardFunc(processNormalKeys);
myInit();
glutMainLoop();
}

...............................................................................

#include <iostream> 

#include <glut.h> 

GLint  WindowHeight = 400; 

GLint  WindowWidth  = 400; 

int count=0;

int a1,b1;

//------------------------------------------------------------------- 

void myInit(void) 

{ 

glClearColor(0.0, 0.0, 1.0, 0.0); // set the background to blue 

glColor3f(1.0f, 1.0f, 1.0f);      // set the drawing color to white 

glPointSize(4.0); 

glMatrixMode(GL_PROJECTION); 

glLoadIdentity(); 

gluOrtho2D(0.0,(float) WindowWidth,0.0, (float) WindowHeight); 

} 

//------------------------------------------------------------------- 

void myDisplay(void) 

{ 

  glClear( GL_COLOR_BUFFER_BIT ); 

  glFlush(); 

} 

//------------------------------------------------------------------- 

void draw(int x, int y)  

{

if (count<2)

{

a1=x;

b1=y;

glBegin(GL_POINTS); 

glVertex2i(x, y); 

glEnd(); 

}

else

{

glColor3f(1.0f, 0.0f, 0.0f);      // set the drawing color to red

glBegin(GL_LINES); // start drawing in 'line' mode

    glVertex2i( x, y); // specify the lines geometry

    glVertex2i( a1, b1);

glEnd();

count=0;

}

  

glFlush();

}

//------------------------------------------------------------------- 

void myMouse(int button, int state, int x, int y) 

{ 

if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN) 

{ 

count++;

draw(x, WindowHeight-y);

} 

} 

void processNormalKeys(unsigned char key, int x, int y){

if (key=='q')

exit(0);

}

//------------------------------------------------------------------- 

void main( int argc, char **argv) 

{ 

glutInit(&argc, argv); 

glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB );  

glutInitWindowSize(WindowWidth,WindowHeight); 

glutInitWindowPosition(0,0); 

glutCreateWindow("Mouse Input"); 

glutDisplayFunc(myDisplay); 

glutMouseFunc(myMouse); 

glutKeyboardFunc(processNormalKeys);

myInit(); 

glutMainLoop(); 

}

...............................................

#include <glut.h>  // Note: this automatically includes other 

                      // required header files, including: 

                      //    glu.h      (GL utility functions) 

                      //    gl.h       (GL functions) 

                      //    windows.h  (Microsoft windows stuff) 

int red=0.0,green=0.0,blue=0.0;

void init(void)

{

  glClearColor(1.0, 1.0, 1.0, 0.0); // set the background to white

  glMatrixMode(GL_PROJECTION); // set projection parameters

  glLoadIdentity();

  gluOrtho2D(0.0,640.0,0.0,480.0);

}

void lineSegment(void)

{

  glClear( GL_COLOR_BUFFER_BIT ); // Clear display window

  glColor3f(red,green, blue);      // set the drawing color to red

   glBegin(GL_TRIANGLES); // start drawing in 'line' mode

    glVertex2i( 50, 200); // specify the lines geometry

    glVertex2i( 150, 350);

glVertex2i(250, 200);

// end drawing 

  glEnd();

  glFlush(); // send any buffered output to  

                                    // the OpenGL rendering process 

}

void processNormalKeys(unsigned char key, int x, int y){

switch(key) {

case 'r' :

red = 1.0;

green = 0.0;

blue = 0.0; break;

case 'g' :

red = 0.0;

green = 1.0;

blue = 0.0; break;

case 'b' :

red = 0.0;

green = 0.0;

blue = 1.0; break;

default : exit(0);

}

lineSegment();

}

//-------------------------------------------------------------------

void main( int argc, char **argv)

{

  glutInit(&argc, argv); // Initialize GLUT

  glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB ); // Set display mode

  glutInitWindowPosition(100,200); // Set top-left display window position

  glutInitWindowSize(320,320); // Set display window width and height

  glutCreateWindow("An Example");// Create display window

  

  init();   // Execute initialization procedure

  glutDisplayFunc(lineSegment); // Send graphics to display window

  glutKeyboardFunc(processNormalKeys);

  glutMainLoop(); // Display everything and wait

}