-------- Original-Nachricht -------- > Datum: Mon, 30 Jan 2012 18:52:39 -0600 > Von: Carsten Neumann <carsten_neum...@gmx.net> > An: opensg-users@lists.sourceforge.net > CC: Dirk Reiners <dirk.rein...@gmail.com> > Betreff: Re: [Opensg-users] OpenSG1.8 - Material Error
> Hello Michael, > > On 01/26/2012 08:14 AM, Michael Raab wrote: > > I have some news on that. It seems that in general the material handling > works well as expected. The problem I described constists actually of two > problems: > > 1.) The wrong color when I switch to non-lit material on materialGroup3: > > I think that was caused by an error in OpenSG. When changing the active > materialchunk during rendering, there is a glColor4fv call missing. So > OpenGL takes the color of the last material when rendering a non-lit > geometry... > > Please have a look at OSGMaterialChunk.cpp > > function: void MaterialChunk::changeFrom(DrawActionBase *, StateChunk * > old_chunk, UInt32) > > There you will find the following statement: > > > > if(getColorMaterial() != GL_NONE || getBackColorMaterial() != GL_NONE) > > glColor4fv(_sfDiffuse.getValue().getValuesRGBA()); > > > > Function MaterialChunk::activate() doesn't have that if condition but > the glColor4fv call so I decided to comment that if condition out. Would you > please verify if that is resonable in all cases? For our case that fixes > the problem... > > thanks for the analysis. There is definitely something wrong with these > lines (at the very least activate() and changeFrom() should behave the > same way ;) ). > I'd say if ColorMaterial != GL_NONE the expectation is that the geometry > has vertex colors to be used in lighting calculations (the whole point > of glColorMaterial()), so the tests actually look backwards to me. > > Dirk: do you remember what the desired behavior here should be? To me it > seems sensible to use the diffuse color as current color (on geometry > with vertex colors those take precedence anyway) if ColorMaterial is > GL_NONE. > > > 2.) White (over lit??) geomety: That seems not to be caused by material > settings (as far as I can see with my debug prints). All materials seem to > be correctly set, the OpenGL command output got from gDEBugger proves that. > So that seems to be caused by the geometry itself. In our case the > rendered geometry has a transformation above. I tried to merge that > transformtion > into the geometry itself and the problem seems to be solved. I'll send you > a before/after example (including screenshots and OpenGL trace) off the > list... > > But I have no idea how the transformation may damage the rendering that > much... > > Hmm, the only transforms that cause funny effects i can think of are > ones that contain negative scale (possibly only on one axis, to go from > left to right-handed coordinate systems). Is that (or something equally > "unusual") the case here? > The OpenGL traces you sent are very similar, the only difference is that > in the broken case three display lists (ids 3,4,44) are called while in > the working case just one (id 45). Ok, I think I may got the reason but I do not understand it. It seems to be the scale factor at the transformation core above the 3 geometries. The factor is (0.001, 0.001, 0.001). If I multiply that factor directly onto the vertices the rendering becomes correctly shaded. If I simply set this factor to (1.0, 1.0, 1.0) the geometry is shaded correctly as well but unfortunately way to large.. ;-) I would guess that this transformation is quite usual soI do not understand why this may cause problems... I'll send you the geometry that causes that problems off the list. Thanks, Michael > Cheers, > Carsten > > ------------------------------------------------------------------------------ > Keep Your Developer Skills Current with LearnDevNow! > The most comprehensive online learning library for Microsoft developers > is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, > Metro Style Apps, more. Free future releases when you subscribe now! > http://p.sf.net/sfu/learndevnow-d2d > _______________________________________________ > Opensg-users mailing list > Opensg-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/opensg-users -- Empfehlen Sie GMX DSL Ihren Freunden und Bekannten und wir belohnen Sie mit bis zu 50,- Euro! https://freundschaftswerbung.gmx.de ------------------------------------------------------------------------------ Keep Your Developer Skills Current with LearnDevNow! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-d2d _______________________________________________ Opensg-users mailing list Opensg-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/opensg-users
