How to display specular spot in an object in OpenGL - opengl

Question

I am creating a sphere. The light source (ambient and diffuse lighting) works well. Only the specular light that doesn't show up in any part of the sphere.
The material code seems not working. I deleted the line and the result is also the same.
The result I want is the sphere rotates with white spot on it in order to look real.
Am I missing any required configuration for lighting?
Is there any solution?
Thanks.
float angle = 0.0f;
void initRendering(){
glEnable(GL_DEPTH_TEST);
glEnable(GL_COLOR_MATERIAL);
glEnable(GL_NORMALIZE);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glEnable(GL_LIGHT1);
}
void draw(){
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glColor3f(1.0f, 0.0f, 0.0f);
glPushMatrix();
glRotatef(angle, 0.0, 1.0, 0.0);
glutSolidSphere(0.5, 20, 20);
glPopMatrix();
GLfloat ambientColor[] = {0.0f, 0.0f, 0.0f, 1.0f};
GLfloat diffuseColor[] = {1.0f, 1.0f, 1.0f, 1.0f};
GLfloat specularColor[] = {1.0f, 1.0f, 1.0f, 1.0f};
GLfloat lightPosition[] = {0.0f, 5.0f, -3.0f, 0.0f};
GLfloat mat_specular[] = { 0.8f, 0.8f, 0.8f, 1.0f };
glLightfv(GL_LIGHT0, GL_AMBIENT, ambientColor);
glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuseColor);
glLightfv(GL_LIGHT0, GL_SPECULAR, specularColor);
glLightfv(GL_LIGHT0, GL_POSITION, lightPosition);
glColorMaterial(GL_FRONT, GL_AMBIENT_AND_DIFFUSE);
glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular);
glMateriali(GL_FRONT, GL_SHININESS, 100);
angle+=0.1f;
glutPostRedisplay();
glutSwapBuffers();
}
main(){
glutInitDisplayMode(GLUT_DOUBLE | GLUT_DEPTH | GLUT_RGBA);
glutInitWindowPosition(100, 100);
glutInitWindowSize(600, 600);
glutCreateWindow("Sphere");
glClearColor(1.0, 1.0, 1.0, 1.0);
initRendering();
glutDisplayFunc(draw);
glutMainLoop();
}

Answer 1

The default for specular light is to add to the colour evaulated in the diffuse illumination step. The specular intensity is modulated by the specular set. You've set this colour to "black", so it adds literally zero.
GLfloat mat_specular[] = { 0.8f, 0.8f, 0.8f, 1.0f };
// …
glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular);
I'd start by actually not inhibiting the specular term.