pfMakeCoordMat R*P*H*T which first?

New Message Reply Date view Thread view Subject view Author view

Sam Chu (c00chu00++at++nchc.gov.tw)
Tue, 9 Dec 1997 10:52:55 +0800 (CST)

Hi Performers:

  Though this is a simple question, it confuse me a lot.

  1. In pfMakeCoordMat(pfMatrix dst, const pfCoord *c) sets dst to
     the matrix which rotates by the Euler transform specified by c->hpr
     and translates by c->xyz, i.e. dst = R*P*H*T
     Q: Is that translate first or rotate first?

  2.pfPreRotMat(dst,degrees,x,y,z); dst = R(degrees, x,y,z) * m,
    Q: Is that Rotate first, or m operation first?

  3. I don't quite understatnd that the meaning differ between pfPreRotMat and
     pfPostRotMat? Can I say that pfPre* is operate on local coordinate and
     pfPost* is operate on the globle coordinate?

  Thank you for your assistance.

Sam Chu
National Center for High-Performance Computing
Scientific Visualization Lab Email: c00chu00++at++nchc.gov.tw
Tel: (886)35-776085 Ext 248 Fax : (886)35-773538
=======================================================================
List Archives, FAQ, FTP: http://www.sgi.com/Technology/Performer/
            Submissions: info-performer++at++sgi.com
        Admin. requests: info-performer-request++at++sgi.com

New Message Reply Date view Thread view Subject view Author view

This archive was generated by hypermail 2.0b2 on Mon Aug 10 1998 - 17:56:21 PDT

This message has been cleansed for anti-spam protection. Replace '++at++' in any mail addresses with the '@' symbol.