How to make an Analog Clock in OpenGL (cmplete code)

Coading in OpenGL is a fun . Here in this post you will learn to make an analog clock in OpenGL.



// GLclock.c
// A openGL example program, displays a 3D clock face
// Happy Coding
// Keyboard inputs: [ESC] = quit
// 'L' = enables/disables lighting
// 'V' = toggle ortho/prespective view


#ifdef _MSC_VER
#define _CRT_SECURE_NO_WARNINGS
#endif

#include <GL/glut.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <time.h>

// define glu objects


GLUquadricObj *Cylinder;
GLUquadricObj *Disk;

struct tm *newtime;
time_t ltime;

GLfloat rx, ry, rz, angle;

// lighting
GLfloat LightAmbient[] = { 0.5f, 0.5f, 0.5f, 1.0f };
GLfloat LightDiffuse[] = { 0.5f, 0.5f, 0.5f, 1.0f };
GLfloat LightPosition[] = { 5.0f, 25.0f, 15.0f, 1.0f };
GLfloat mat_specular[] = { 1.0, 1.0, 1.0, 1.0 };

static int light_state = 1; // light on = 1,  off = 0
static int view_state = 1; // Ortho view = 1, Perspective = 0


void Sprint(int x, int y, char *st)
{
int l, i;

l = strlen(st);
glRasterPos3i(x, y, -1);
for (i = 0; i < l; i++)
{
glutBitmapCharacter(GLUT_BITMAP_TIMES_ROMAN_24, st[i]);
}

}

static void TimeEvent(int te)
{
int timent;
int i;
float M_TWOPI = 2 * 3.1416;

rx = 30 * cos(angle);
ry = 30 * sin(angle);
rz = 30 * cos(angle);
angle += 0.01;
if (angle > M_TWOPI) angle = 0;

glutPostRedisplay();
glutTimerFunc(100, TimeEvent, 1);
}

void init(void)
{


glClearColor(0.0, 0.0, 0.0, 0.0);
glShadeModel(GL_SMOOTH);
glEnable(GL_DEPTH_TEST);
// Lighting in the scene
glLightfv(GL_LIGHT1, GL_AMBIENT, LightAmbient);
glLightfv(GL_LIGHT1, GL_DIFFUSE, LightDiffuse);
glLightfv(GL_LIGHT1, GL_POSITION, LightPosition);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT1);


Cylinder = gluNewQuadric();
gluQuadricDrawStyle(Cylinder, GLU_FILL);
gluQuadricNormals(Cylinder, GLU_SMOOTH);
gluQuadricOrientation(Cylinder, GLU_OUTSIDE);
gluQuadricTexture(Cylinder, GL_TRUE);

Disk = gluNewQuadric();
gluQuadricDrawStyle(Disk, GLU_FILL);
gluQuadricNormals(Disk, GLU_SMOOTH);
gluQuadricOrientation(Disk, GLU_OUTSIDE);
gluQuadricTexture(Disk, GL_TRUE);


}

void Draw_gear(void)
{

int i;
glPushMatrix();
gluCylinder(Cylinder, 2.5, 2.5, 1, 16, 16);
gluDisk(Disk, 0, 2.5, 32, 16);
glTranslatef(0, 0, 1);
gluDisk(Disk, 0, 2.5, 32, 16);
glPopMatrix();
for (i = 0; i < 8; i++)
{
glPushMatrix();
glTranslatef(0.0, 0.0, 0.50);
glRotatef((360 / 8) * i, 0.0, 0.0, 1.0);
glTranslatef(3.0, 0.0, 0.0);
glutSolidCube(1.0);
glPopMatrix();
}


}

void Draw_clock(GLfloat cx, GLfloat cy, GLfloat cz)
{

int hour_ticks, sec_ticks;
glPushMatrix();

glTranslatef(cx, cy, cz);
glRotatef(180, 1.0, 0.0, 0.0);


glPushMatrix(); // Drawing large wire cube
glColor3f(1.0, 1.0, 1.0);
glTranslatef(0.0, 0.0, 6.0);
glutWireCube(14.0);
glPopMatrix();

glPushMatrix(); // Drawing clock face
glTranslatef(0, 0, 1.0);
gluDisk(Disk, 0, 6.75, 32, 16);

glPopMatrix();

glPushMatrix();// Drawing hour hand
glColor3f(1.0, 1.5, 0.5);
glTranslatef(0, 0, 0.0);
glRotatef((360 / 12) * newtime->tm_hour + (360 / 60) * (60 / (newtime->tm_min + 1)), 0.0, 0.0, 1.0);
glPushMatrix();
glTranslatef(0.0, 0.0, 2.0);
Draw_gear();
glPopMatrix();
glRotatef(90, 1.0, 0.0, 0.0);
gluCylinder(Cylinder, 0.75, 0, 4, 16, 16);
glPopMatrix();

glPushMatrix();// Drawing minute hand
glColor3f(1.5, 1.5, 1.0);
glTranslatef(0, 0, 0.0);
glRotatef((360 / 60) * newtime->tm_min, 0.0, 0.0, 1.0);
glPushMatrix();
glTranslatef(0.0, 0.0, 3.0);
glScalef(0.5, 0.5, 1.0);
Draw_gear();
glPopMatrix();
glRotatef(90, 1.0, 0.0, 0.0);
gluCylinder(Cylinder, 0.5, 0, 6, 16, 16);
glPopMatrix();

glPushMatrix();// Drawing second hand
glColor3f(1.0, 0.0, 1.5);
glTranslatef(0, 0, -0.0);
glRotatef((360 / 60) * newtime->tm_sec, 0.0, 0.0, 1.0);
glPushMatrix();
glTranslatef(0.0, 0.0, 4.0);
glScalef(0.25, 0.25, 1.0);
Draw_gear();
glPopMatrix();
glRotatef(90, 1.0, 0.0, 0.0);
gluCylinder(Cylinder, 0.25, 0, 6, 16, 16);
glPopMatrix();


for (hour_ticks = 0; hour_ticks < 12; hour_ticks++)
{
glPushMatrix();// Drawing next arm axis.
glColor3f(0.0, 1.0, 1.0); //Now give it a color
glTranslatef(0.0, 0.0, 0.0);
glRotatef((360 / 12) * hour_ticks, 0.0, 0.0, 1.0);
glTranslatef(6.0, 0.0, 0.0);
glutSolidCube(1.0);

glPopMatrix();
}
for (sec_ticks = 0; sec_ticks < 60; sec_ticks++)
{
glPushMatrix();
glTranslatef(0.0, 0.0, 0.0);
glRotatef((360 / 60) * sec_ticks, 0.0, 0.0, 1.0);
glTranslatef(6.0, 0.0, 0.0);
glutSolidCube(0.25);
glPopMatrix();
}


glPopMatrix();

}


void display(void)
{

time(&ltime); // Get time
newtime = localtime(&ltime); // Convert to local time

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

// easy way to put text on the screen.
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-8.0, 8.0, -8.0, 8.0, 1.0, 60.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glDisable(GL_LIGHTING);
glDisable(GL_COLOR_MATERIAL);

// Put view state on screen
glColor3f(1.0, 1.0, 1.0);
if (view_state == 0)
{
Sprint(-3, -4, "Perspective view");
}
else Sprint(-2, -4, "Ortho view");


Sprint(-4, -8, asctime(newtime));

// Turn Perspective mode on/off
if (view_state == 0)
{
glMatrixMode(GL_PROJECTION);
glLoadIdentity();

gluPerspective(60.0, 1, 1.0, 60.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluLookAt(rx, 0.0, rz, 0.0, 0.0, -14.0, 0, 1, 0);
}

if (light_state == 1)
{
glEnable(GL_LIGHTING);
glEnable(GL_COLOR_MATERIAL);  // Enable for lighing
}
else
{
glDisable(GL_LIGHTING);
glDisable(GL_COLOR_MATERIAL);  // Disable for no lighing
}

Draw_clock(0.0, 0.0, -14.0);



glutSwapBuffers();
}

void reshape(int w, int h)
{
glViewport(0, 0, (GLsizei)w, (GLsizei)h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
}

void keyboard(unsigned char key, int x, int y)
{
switch (key)
{
case 'L':
light_state = abs(light_state - 1);
break;
case 'V':
view_state = abs(view_state - 1);
break;
case 27:
exit(0); // exit program when [ESC] key presseed
break;
default:
break;
}

}

int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
glutInitWindowSize(500, 500);
glutInitWindowPosition(10, 10);
glutCreateWindow(argv[0]);
glutSetWindowTitle("GLclock");
init();
glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutKeyboardFunc(keyboard);
glutTimerFunc(10, TimeEvent, 1);
glutMainLoop();
return 0;
}

Happy coading............