[vtkusers] Modifications to vtkOpenGLPolyDataMapper.cxx vtkOpenGLProperty.cxx

[John Biddiscombe]

Goodwin,

> John Biddiscombe inquired about this back in Oct 1999...

Wow! someone was listening. Nice work.

I'll have a quick play with your modified files and check them in if I don't
see any problems.

JB


> I've made some change to my vtk src that may be of interest:
>
> 1. Allows backface/frontface culling in wireframe and points
representation.
> 2. Allows a backface property to be set in wireframe and points
> representation.
> 3. Speeds up wireframe rendering by 20% with BackfaceCullingOff and by
110%
> with BackfaceCullingOn (SB's bench-sphere.tcl on Dell Inspiron 3800- ATI
> Rage Mobility graphics card). Probably speeds up points rendering too
> (haven't tested it though). Other representation are unaffected- triangle
> strips are still the fastest primitive to render.
> 4. EdgeVisibilty could now be enabled when rendering surfaces in vtk
(would
> take some more hacking). It seems EdgeVisibility is only used in the
> GeomView exporter.
>
> In a nutshell, the changes are that vtkOpenGLPolyDataMapper.cxx always
draws
> triangles and vtkOpenGLProperty.cxx switches the representation using
> glPolygonMode( )
>
> John Biddiscombe inquired about this back in Oct 1999... here's the
thread:
> http://public.kitware.com/pipermail/vtkusers/1999-October/002446.html.
Maybe
> there should be a feature wish-list or bug-ín page on the website?
>
> Here are the diffs (compared to nightly 10/10) and the files are attached:
>
> Diff for vtkOpenGLPolyDataMapper.cxx:
>
> 2487a2488,2509
> >   switch (rep)
> >     {
> >     case VTK_POINTS:
> >       glFunction[0]  = GL_POINTS;
> >       glFunction[1]  = GL_POINTS;
> >       glFunction[2]  = GL_POINTS;
> >       glFunction[3]  = GL_POINTS;
> >       break;
> >     case VTK_WIREFRAME:
> >       glFunction[0] = GL_POINTS;
> >       glFunction[1] = GL_LINE_STRIP;
> >       glFunction[2] = GL_LINE_STRIP;
> >       glFunction[3] = GL_LINE_LOOP;
> >       break;
> >     case VTK_SURFACE:
> >       glFunction[0] = GL_POINTS;
> >       glFunction[1] = GL_LINE_STRIP;
> >       glFunction[2] = GL_TRIANGLE_STRIP;
> >       glFunction[3] = GL_POLYGON;
> >       break;
> >     default:
> >       vtkErrorMacro(<< "Bad representation sent\n");
> 2491a2514,2515
> >       break;
> >     }
> 2647c2671
> < /*
> ---
> >
> 2704c2728
> < */
> ---
> >
> 2804,2805c2828
> <   draw3(aPrim, aGlFunction, cellNum, p, n, c, t, ren, noAbort);
> < /*
> ---
> >   draw2(aPrim, aGlFunction, cellNum, p, n, c, t, ren, noAbort);
> 2810c2833
> < */
> ---
> >
>
> Diff for vtkOpenGLProperty.cxx:
>
> 65,70d64
> <       if (this->GetRepresentation() == VTK_WIREFRAME)
> <               glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
> <       else if (this->GetRepresentation() == VTK_SURFACE)
> <               glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
> <       else
> <               glPolygonMode(GL_FRONT_AND_BACK, GL_POINT);
> 76,81d69
> <       if (this->GetRepresentation() == VTK_WIREFRAME)
> <               glPolygonMode(GL_FRONT, GL_LINE);
> <       else if (this->GetRepresentation() == VTK_SURFACE)
> <               glPolygonMode(GL_FRONT, GL_FILL);
> <       else
> <               glPolygonMode(GL_FRONT, GL_POINT);
> 87,92d74
> <       if (this->GetRepresentation() == VTK_WIREFRAME)
> <               glPolygonMode(GL_BACK, GL_LINE);
> <       else if (this->GetRepresentation() == VTK_SURFACE)
> <               glPolygonMode(GL_BACK, GL_FILL);
> <       else
> <               glPolygonMode(GL_BACK, GL_POINT);
>
>
>
>
>