i do not know what is happening with my rendering,
before i was using another computer to render and everything normal,
but then i migrate the program to another computer (acer laptop), then the graphic become like this,
what had i done wrong?

It is like having some missing fragments, but also looks like the shading is having problem, i don know what happened.



Code :
// Set color to use when clearing the background.
	glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
	glClearDepth(1.0f);
 
    /* Set up some light sources */
    glLightfv(GL_LIGHT0, GL_POSITION, light0_pos);
    glLightfv(GL_LIGHT0, GL_DIFFUSE, light0_color);
	glLightf(GL_LIGHT0, GL_CONSTANT_ATTENUATION, 0.2);
	glLightf(GL_LIGHT0, GL_LINEAR_ATTENUATION, 0.00001);
	//glLightf(GL_LIGHT0, GL_QUADRATIC_ATTENUATION, 0.00);
    glLightModelfv(GL_LIGHT_MODEL_AMBIENT, ambient_light);
 
 
    glEnable(GL_LIGHT0);
    glEnable(GL_LIGHTING); 
 
	// Turn on backface culling
	glFrontFace(GL_CW);
	glCullFace(GL_BACK);
 
	// Turn on depth testing
	glEnable(GL_DEPTH_TEST);
	glDepthFunc(GL_LEQUAL);
 
    glShadeModel(GL_SMOOTH);
 
	// enable blending
	glEnable(GL_BLEND);
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 
	glViewport(0, 0, width, height);	
 
    /* Create a viewing frustum */
    glMatrixMode(GL_PROJECTION);
 
    glLoadIdentity();
 
    gluPerspective(FOV_ANGLE, 1.0f, CLIPPLANE_NEAR, CLIPPLANE_FAR);
    gluLookAt(VIEWER_X, VIEWER_Y, -VIEWER_Z, CENTER_X, CENTER_Y, CENTER_Z, UP_X, UP_Y, UP_Z);
 
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();

Above are my setup code for rendering, i wonder what am i missing to get it right.