Hi Carsten,
On 01/30/2012 06:52 PM, Carsten Neumann wrote:
>
> 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.
I would agree. But I do remember going back and forth on this part, and there
some situations that were problematic, I just don't remember exactly what they
were.
For now I would do your change.
> 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).
On 01/31/2012 05:06 AM, Michael Raab wrote:
>
> 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.
Scales are always a problem with lighting, that's what GL_NORMALIZE is for.
Normally that is always enabled in OpenSG (inside OSG::Window::setupGL, usually
called from xxxWindow::init). I don't know how you setup your window, maybe you
can check the OpenGL log to make sure glEnable(GL_NORMALIZE) is called.
Yours
Dirk
--
Dirk Reiners [email protected]
"God must really love stupid people. Why else would he make so many of them?"
Walter Rothschild
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