My vertex cords are :
Code :
GLfloat vertices[]=
    {
        0.5f,0.5f,0.5f,                                   
        -0.5f,0.5f,0.5f,
        -0.5f,-0.5f,0.5f,
        0.5f,-0.5f,0.5f,//face 1
 
        0.5f,-0.5f,-0.5f,
        -0.5f,-0.5f,-0.5f,
        -0.5f,0.5f,-0.5f,
        0.5f,0.5f,-0.5f,//face 2
 
        0.5f,0.5f,0.5f,
        0.5f,-0.5f,0.5f,
        0.5f,-0.5f,-0.5f,
        0.5f,0.5f,-0.5f,//face 3                
 
        -0.5f,0.5f,0.5f,
        -0.5f,0.5f,-0.5f,
        -0.5f,-0.5f,-0.5f,
        -0.5f,-0.5f,0.5f,//face 4
 
        0.5f,0.5f,0.5f,
        0.5f,0.5f,-0.5f,
        -0.5f,0.5f,-0.5f,
        -0.5f,0.5f,0.5f,//face 5
 
        -0.5f,-0.5f,0.5f,
        -0.5f,-0.5f,-0.5f,
        0.5f,-0.5f,-0.5f,
        0.5f,-0.5f,0.5f//face 6     
 
    };

now, i am changing z cords by:

Code :
for(int i=0;i<24;i++)
    vertices[i*3+2]*=10
glDepthRange(0,10.0);

Now, i am expecting that z cords will be mapped to -0.5 to 0.5 range due to glDepthRange call and i can see a proper cube, but it gives o/p as that of when i comment glDepthRange call above with distorted geometry.