Yes, lighting works.  Remeber you have to enable both your light and the lighting system.

gl.glEnable(GL.GL_LIGHT1);
gl.glEnable(GL.GL_LIGHTING);

Hi,

I'll start in little specs. I have a concept of a mesh which consists of triangles. The mesh knows how to calculate the normals and I am assured that the normals are correct.

Actually, there only difference between the two spheres on the image is GL_FLAT vs. GL_SMOOTH and I would argue that even on the left GL_FLAT image the shading is wrong.


     gl.glMaterialfv(GL.GL_BACK, GL.GL_AMBIENT_AND_DIFFUSE, myAmbientColorBack.getComponents(null) );
     gl.glMaterialfv(GL.GL_FRONT, GL.GL_AMBIENT_AND_DIFFUSE, myAmbientColorFront.getComponents(null) );

     gl.glMaterialfv(GL.GL_FRONT_AND_BACK, GL.GL_EMISSION, ZERO );

     gl.glMaterialfv(GL.GL_FRONT_AND_BACK, GL.GL_SPECULAR, Color.WHITE.getComponents(null) );
     gl.glPolygonMode(GL.GL_FRONT_AND_BACK, GL.GL_FILL);

     for (int t = 0; t < myMesh.pGetNumberOfElements(); t++) {
       Element elem = myMesh.pGetElement(t);
       gl.glBegin(GL.GL_TRIANGLES);
       for (int v = 0; v < elem.pGetNumberOfNodes(); v++) {
         VDouble x = myMesh.pGetX(elem.pGetNode(v));
         VDouble n = normals[elem.pGetNode(v)];
         gl.glVertex3d(x.pGet(0), x.pGet(1), x.pGet(2));
         gl.glNormal3d(n.pGet(0), n.pGet(1), n.pGet(2));
       }
       gl.glEnd();
     }
   }


Then elsewhere in my init() I have:

     GL gl = inDrawable.getGL();

     gl.glClearColor(1f, 1f, 1f, 1f);

     gl.glEnable(GL.GL_DEPTH_TEST);
     gl.glEnable(GL.GL_POLYGON_OFFSET_FILL);
     gl.glEnable(GL.GL_POLYGON_OFFSET_LINE);

     // Lights
     gl.glEnable(GL.GL_LIGHTING);
     gl.glLightModelfv(GL.GL_LIGHT_MODEL_AMBIENT, new float[] { .6f, .6f, .6f, 1f });

     myLight0 = new GLUtils.Light(myCanvas3D,  // Self-explanatory, really
GL.GL_LIGHT0,
                                  0f, 0f, 3f,
                                  Color.GRAY,
                                  Color.BLACK);

// Uncomment for FLAT.
//      gl.glShadeModel(GL.GL_FLAT);


Thanks for taking a look at this.

Dola

Yep, GKW's  got it.  Swap those and give it another try.  Considering the cases where the lighting is wrong, usually two vertices are correct and only one is off - given that normal n is being applied to vertex n+1 in each "element", this kind of thing is what you'd expect.

I presume in each triangle the normal is the same for all vertices, and that your sphere is made up of a number of "elements"?  The bad normals are probably a default normal being applied to the first vertex in each "element", or something similar to that.



Yep, undoubtedly.  The problem is that when in GL_FLAT mode, in each triangle only one vertex's normal will be used.  So the errors are that much harder to spot!

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