Hi, I made small algorithm when I am manually computing phong illumination. <div>What illumination formula is used in VTK ? It looks that is not phong illumination. </div><div>I would need obtain same color as VTK made is. </div>
<div>---------------------------</div><div>I made small test : </div><div><br></div><div><div>My 'phong' illumination formula is :</div><div> I = kd * abs((n*l)) + ks * abs(h*n) ; </div><div>where diffuse term kd = 0.6 and specular term ks = 0.4, </div>
<div>view vector is default v = (0,0,1), light vector l is also located at (0,0,1), </div><div>n is normal at the point, and h is standard halfway vector.</div><div><br></div><div>For comparison with VTK I used same settings for drawing purely with vtk setting property :</div>
<div>actor->GetPorperty()->SetAmbient(0);</div><div>actor->GetProperty()->SetDiffuse(kd);</div><div>actor->GetProperty()->SetSpecular(ks)</div><div><br></div><div>The results are different, see attached picture.</div>
<div><br></div><div>Therefore it looks that VTK is not using pure phong. So what illumination formula is used in VTK ? </div><div>It is done via shaders ? Or it is somewhere computed ? </div><div>Where is made color computation in vtk, where those ambient, diffuse, specular coefficient are used ? </div>
<div>I found method GetColor() in vtkProperty() , but it has different meaning, but i am searching for s.t. like this.</div><div><br></div><div><br></div><div>Any hint would be highly appreciate.</div><div>Thanks in advance. </div>
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