Shading issue in opengl glsl

Question

The 3d obj(wavefront) model I'm loading and trying to apply some shading (through fixed pipeline+shaders combined for the purpose of simplicity) is being displayed wrong.

Now there are some problems i think i can spot. The light issue: doesn't seem static. It seems to rotate as i rotate the object with transformations. I am using gluLookAt+gluPerspective to set my view matrix and i've read that if you apply the light in opengl before applying gluLookAt your lights remain static in theory. This doesn't seem to be the case here.

Issue 2 is the way the model is being shaded. It's sort of choppy instead of smooth and i'm not even sure why that ring effect appears. I've loaded my mesh in ShaderMaker and applied my vertex+fragment shader also and everything draws perfect. It seems like i'm doing something wrong in my drawing routine.

My Vertex shader:

#version 120

varying vec3 N;
varying vec3 v;
void main(void)  
{    
   v = vec3(gl_ModelViewMatrix * gl_Vertex);      
   N = normalize(gl_NormalMatrix * gl_Normal);
   gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;  
}

My Fragment shader:

#version 120

varying vec3 N;
varying vec3 v;
#define MAX_LIGHTS 2
void main (void)  
{  
   vec4 finalColour;

        vec4 amb;
        amb = vec4(0.2,0.2,0.2,1.0);

        vec4 diff;
        diff = vec4(1.0,1.0,1.0,1.0);

       vec3 L = normalize(gl_LightSource[0].position.xyz - v);  
       vec3 E = normalize(v);
       vec3 R = normalize(reflect(L,-N));  
       //vec4 Iamb = gl_FrontLightProduct[i].ambient;    
        vec4 Iamb = amb;

        //vec4 Idiff = gl_FrontLightProduct[i].diffuse * max(dot(N,L), 0.0);
       vec4 Idiff = diff * max(dot(N,L), 0.0);

        Idiff = clamp(Idiff, 0.0, 1.0);    
       vec4 Ispec = gl_FrontLightProduct[0].specular
                    * pow(max(dot(R,E),0.0),0.0*gl_FrontMaterial.shininess);
       Ispec = clamp(Ispec, 0.0, 1.0);
       finalColour += Iamb + Idiff;

   gl_FragColor = gl_FrontLightModelProduct.sceneColor + finalColour;
}

EDIT :: Added my drawing routine.

 [[self openGLContext] makeCurrentContext];
    [sM useProgram];


    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_LIGHTING);
    glClearColor(0.0f,0.0f,0.0f,1.0f);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();

    float aspect = (float)1024 / (float)576;

    gluPerspective(15.0, aspect, 1.0, 15.0);

    glMatrixMode(GL_MODELVIEW);
    float lpos[4] = {0.0,2.0,0.0,1.0};
    glLoadIdentity();
    glLightfv(GL_LIGHT0, GL_POSITION, lpos);

    gluLookAt(0.0, 0.0, 10.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);


    glTranslatef(0.0f, 0.0f, 0.0f);
    glScalef(0.5f, 0.5f, 0.5f);

    glRotatef(self.rotValue, 1.0f, 1.0f, 0.0f);



    glEnableClientState(GL_VERTEX_ARRAY);  
    glEnableClientState(GL_NORMAL_ARRAY);
    NSLog(@"%i", self.W);

    if(self.W == NO)
    {
        glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
    } 
    if (self.W == YES)
    {
        glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
    }
    glColor3f(1.0f,0.0f,0.0f);
    glBindBuffer(GL_ARRAY_BUFFER, vBo[0]);
    glVertexPointer(3, GL_FLOAT, 0, 0);

    glBindBuffer(GL_ARRAY_BUFFER, vBo[1]);
    glNormalPointer(GL_FLOAT, 0, 0);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vBo[2]);
    glDrawElements(GL_TRIANGLES, object.indicesCount, GL_UNSIGNED_INT, 0);

    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glDisableClientState(GL_NORMAL_ARRAY);
    glDisableClientState(GL_VERTEX_ARRAY);





    GLenum err = glGetError();
    if (err != GL_NO_ERROR)
        NSLog(@"glGetError(): %i", (int)err);

    [[self openGLContext] flushBuffer];

My shaders are actually borrowed from an online source. I have made my own but i wanted to make sure i use a solid one from someone experienced. I don't intend keeping them until i can fix this problem.

Answer 1

I think i've found the issue. Haven't implemented a solution yet but i am pretty sure the problem lies there. This question is also very relevant to my problem:

Understanding normals indices with Wavefront Obj

The problem was in the way i was handling my core data(from obj file). I was naive enough to believe passing them directly to OpenGL(through VBOs) as i parse them was going to work. Here's a dose of humour to accompany my mistake. I hope my link does not violate guideline rules. Special thanks to Andreas for helping me trace the problem. link

Update: A solution has been implemented and my models now render with correct shading.

I used the vertex and normal faces to rearrange the wavefront data(vertices+normals) into new vectors. I also switched from glDrawElements to glDrawArrays because glDrawElements does not support sending different indices for normal and uv vectors. Although this solution increases loading time and occupied space (since duplicated vertices are not removed from buffer) it is working and meets my needs.