[Plib-users] R: R: R: culling problems w/ off-axis projection
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[Plib-users] R: R: R: culling problems w/ off-axis projection
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From: Paolo L. <p.l...@ci...> - 2010-05-31 08:22:59
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John, > -----Messaggio originale----- > Da: John F. Fay [mailto:joh...@cy...] > Inviato: sabato 29 maggio 2010 4.15 > A: PLIB Users > Oggetto: Re: [Plib-users] R: R: culling problems w/ off-axis > projection > > Paolo, > Message-Id: <201...@yo...> > > Please pardon my delay in answering; May is never a > good month for me. Did this patch get put in already, No. > or did the patch file switch the "from" and "to" versions? Yes. > - John Thanks for taking care of it. Greetings, Paolo > At 09:40 AM 4/21/2010, you wrote: > >John, > > > >Please find attached the patch. > > > >This patch also include a fix to the function > sgQuatToAxisAngle which > >manages cases of Quat's W outside the range [-1:1] (acos undefined). > >For this I used _isnan and _finite functions in MS Visual C++, whose > >availability I ask all of you to verify on other > Plib-supported platforms. > >Otherwise just ignore this second part of the patch. > > > >Thanks a lot, > > > >Paolo Leoncini > > > > > > > -----Messaggio originale----- > > > Da: Fay, John F Dr CTR USAF AFMC 46 SK > > > [mailto:joh...@eg...] > > > Inviato: sabato 17 aprile 2010 18.33 > > > A: PLIB Users > > > Oggetto: Re: [Plib-users] R: culling problems w/ off-axis > projection > > > > > > Paolo, > > > > > > Congratulations and very good on having solved the > problem. > > > Is there a code change that you want me to put into Subversion? > > > > > > Dr. John F. Fay > > > Technical Fellow > > > Jacobs Technology TEAS Group > > > 850-883-1294 > > > > > > > > > -----Original Message----- > > > From: Paolo Leoncini [mailto:p.l...@ci...] > > > Sent: Monday, April 12, 2010 3:21 AM > > > To: 'PLIB Users' > > > Subject: [Plib-users] R: culling problems w/ off-axis projection > > > > > > Dear friends, > > > > > > I think to have solved the problem. > > > > > > > -----Messaggio originale----- > > > > Da: p.l...@ci... [mailto:p.l...@ci...] > > > > Inviato: martedì 6 aprile 2010 11.19 > > > > A: pli...@li... > > > > Oggetto: [Plib-users] culling problems w/ off-axis projection > > > > > > > > Dear all, > > > > > > > > I'm doing off-axis projection (the most general form of > > > > projection) by translating the four corners of the > screen into a > > > > projection matrix, for which I added a new method to > the sgFrustum > > > > class and to the Context too. The only difference with > > > giving the six > > > > frustum extrema values is that no calculation occurs. > > > Culling seems to > > > > rely only on the projection matrix values, so, apparently, no > > > > difference w/ the on-axis standard case. > > > > > > > > As far as the projection is not far from the on-axis case > > > the culling > > > > gives no problem. Instead when screen position definition > > > results in a > > > > large rotation in the projection matrix objects suddenly > > > disappear and > > > > reappear by apparently no rule. > > > > > > > > Are culling calculations based on a particular form of the > > > projection > > > > matrix? > > > > should culling planes be extracted in a different way to > > > support the > > > > more general case? > > > > > > In sgFrustum::contains( const sgSphere *s ) (sg.cxx), the for the > > > non-ortho case which is presently done this way: > > > > > > sp1 = plane[ SG_LEFT_PLANE ][0] * center[0] + plane[ > > > SG_LEFT_PLANE ][2] * center[2] ; > > > sp2 = plane[ SG_RIGHT_PLANE ][0] * center[0] + plane[ > > > SG_RIGHT_PLANE ][2] * center[2] ; > > > sp3 = plane[ SG_BOT_PLANE ][1] * center[1] + plane[ > SG_BOT_PLANE > > > ][2] * center[2] ; > > > sp4 = plane[ SG_TOP_PLANE ][1] * center[1] + plane[ > SG_TOP_PLANE > > > ][2] * center[2] ; > > > > > > should be substituted by the following general form: > > > > > > sp1 = sgScalarProductVec3 ( plane[ SG_LEFT_PLANE ], > center ) + > > > plane[ SG_LEFT_PLANE ][3] ; > > > sp2 = sgScalarProductVec3 ( plane[ SG_RIGHT_PLANE ], > center ) + > > > plane[ SG_RIGHT_PLANE ][3] ; > > > sp3 = sgScalarProductVec3 ( plane[ SG_BOT_PLANE ], > > > center ) + plane[ > > > SG_BOT_PLANE ][3] ; > > > sp4 = sgScalarProductVec3 ( plane[ SG_TOP_PLANE ], > > > center ) + plane[ > > > SG_TOP_PLANE ][3] ; > > > > > > The hint were just below there (see comment "Note: in the general > > > case, we would have to do:"). > > > I propose to patch it since this general form also manages the > > > default on-axis case, but Steve should definitely give > the go-ahead. > > > Should someone be concerned about performances I could > supply a bit > > > larger patch for introducing the ability to supply the Context a > > > general perspective matrix, so to have the general case only > > > calculated in this eventuality. > > > > > > > Thanks a lot, > > > > > > > > Paolo Leoncini > > > > > > Thanks in advance to a good will updater (John, it's you > as usual?). > > > > > > Paolo Leoncini > > > > > > > > > > -------------------------------------------------------------- > > > > ---------------- > > > > Download Intel® Parallel Studio Eval Try the new > > > software tools > > > > for yourself. Speed compiling, find bugs proactively, and > > > > fine-tune applications for parallel performance. > > > > See why Intel Parallel Studio got high marks during beta. > > > > http://p.sf.net/sfu/intel-sw-dev > > > > _______________________________________________ > > > > plib-users mailing list > > > > pli...@li... > > > > https://lists.sourceforge.net/lists/listinfo/plib-users > > > > > > > > > > > > > -------------------------------------------------------------- > > > ---------------- > > > Download Intel® Parallel Studio Eval Try the new > software tools > > > for yourself. Speed compiling, find bugs proactively, and > fine-tune > > > applications for parallel performance. > > > See why Intel Parallel Studio got high marks during beta. > > > http://p.sf.net/sfu/intel-sw-dev > > > _______________________________________________ > > > plib-users mailing list > > > pli...@li... > > > https://lists.sourceforge.net/lists/listinfo/plib-users > > > > > > -------------------------------------------------------------- > > > ---------------- > > > Download Intel® Parallel Studio Eval Try the new > software tools > > > for yourself. Speed compiling, find bugs proactively, and > fine-tune > > > applications for parallel performance. > > > See why Intel Parallel Studio got high marks during beta. > > > http://p.sf.net/sfu/intel-sw-dev > > > _______________________________________________ > > > plib-users mailing list > > > pli...@li... > > > https://lists.sourceforge.net/lists/listinfo/plib-users > > > > > > > > >------------------------------------------------------------- > ---------- > >------- > > > >_______________________________________________ > >plib-users mailing list > >pli...@li... > >https://lists.sourceforge.net/lists/listinfo/plib-users > > > -------------------------------------------------------------- > ---------------- > > _______________________________________________ > plib-users mailing list > pli...@li... > https://lists.sourceforge.net/lists/listinfo/plib-users > |
