I have come up with a kludge (not a proper fix) for the lack of smoothing in AC3D models in PLIB. The AC3D loader is the only one that actually uses ssgStripify; I believe that's the wrong place to calculate normals, because you've already lost the information in the AC3D file about what surfaces should be smoothed what what vertices are actually shared (rather than just coincident). Still, for now, I've just kludged a short loop into makeNormals in ssgOptimiser.cxx so that all vertices with the same location get treated as identical (and all are smoothed).
Here is a before picture of the DC-3 model in FlightGear: http://www.megginson.com/flightsim/dc3-unsmoothed.png Here is a shot from after my patch was applied: http://www.megginson.com/flightsim/dc3-smoothed.png Since the patch is tiny, I'm attaching it to this message. It is also available online at http://www.megginson.com/flightsim/plib-smoothing.dif A proper solution to this problem will involve modifying the AC3D loader, probably to avoid ssgStripify (since it blows away the normals) and to take advantage of the information that's in the AC3D file, like the other loaders do for their formats. In the meantime, FlightGear users (and others) can apply this patch to their recent CVS plib source trees and get smoothed AC3D models again. Here's the patch: --- ../plib.SAFE/src/ssg/ssgOptimiser.cxx Fri Mar 29 14:16:58 2002 +++ src/ssg/ssgOptimiser.cxx Fri Mar 29 14:21:48 2002 @@ -303,16 +303,22 @@ for ( i = 0 ; i < tnum ; i++ ) { sgVec3 tmp ; + short j ; sgMakeNormal ( tmp, vlist [ tlist [ i*3+ 0 ] ] -> vertex, vlist [ tlist [ i*3+ 1 ] ] -> vertex, vlist [ tlist [ i*3+ 2 ] ] -> vertex ) ; - - sgAddVec3 ( vlist [ tlist [ i*3+ 0 ] ] -> normal, tmp ) ; - sgAddVec3 ( vlist [ tlist [ i*3+ 1 ] ] -> normal, tmp ) ; - sgAddVec3 ( vlist [ tlist [ i*3+ 2 ] ] -> normal, tmp ) ; + + for ( j = 0; j < vnum; j++ ) { + if (sgEqualVec3(vlist[j]->vertex, vlist[tlist[i*3+0]]->vertex)) + sgAddVec3(vlist[j]->normal, tmp); + if (sgEqualVec3(vlist[j]->vertex, vlist[tlist[i*3+1]]->vertex)) + sgAddVec3(vlist[j]->normal, tmp); + if (sgEqualVec3(vlist[j]->vertex, vlist[tlist[i*3+2]]->vertex)) + sgAddVec3(vlist[j]->normal, tmp); + } } - + for ( i = 0 ; i < vnum ; i++ ) if ( sgScalarProductVec2 ( vlist[i]->normal, vlist[i]->normal ) < 0.001 ) sgSetVec3 ( vlist[i]->normal, 0.0f, 0.0f, 1.0f ) ; All the best, David -- David Megginson [EMAIL PROTECTED] _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
