It should be easy for you to determine experientially that post-multiplying two column-major matrices is equivalent to pre-multiplying two row-major matrices. Go to a white board and do the math and you will see that they are identical operations. The difference between OpenGL and OSG is purely in the mathematical notation used to write the algebra; internally, they are identical. -Paul
_____ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of ami guru Sent: Monday, August 25, 2008 2:19 PM To: OpenSceneGraph Users Subject: Re: [osg-users] matrix concept - newbie Hi I am going the the quick starter guide and also the Math Link in the website where Robert and Don explained some issues related to matrix. At some point it is specified that "the pre-multiplication style matrix operation are the opposite of what we usually find in OpenGL documentation". I would like find out how it is happening. As it says that OpenGL notation produces the same result because opengl's post-multiplication notation with column-major matrices is equivalent to osg's pre-multiplication style operators row-major matrices. I would like to understand how and where is that equivalent. It will be nice if you kindly locate me to them. Regards Sajjad On Mon, Aug 25, 2008 at 5:56 PM, Gerrick Bivins <[EMAIL PROTECTED]> wrote: Sounds like he is referring to how OpenGL stores the matrices, as a 1d array of 16 elements, while OSG stores them as a 2d array of 4x4. biv On 8/25/08 10:43 AM, "Robert Osfield" <[EMAIL PROTECTED]> wrote: > Hi Sajjad, > > The OSG only has 4x4 Matrix classes, OpenGL itself also just has 4x4 > matrices, save for some specific uniforms that have 4x3 matrices. > There are no 2D or 1D matrices in either the OSG or OpenGL. > > Could you please explain what you are trying to achieve, then perhaps > others will be able to point you in the right direction. > > Robert. > > On Mon, Aug 25, 2008 at 4:20 PM, ami guru <[EMAIL PROTECTED]> wrote: >> Hello forum, >> >> Quite new to this rendering system. >> >> I would like to know which file does contain the mapping of the OSG >> matrix(2D) to the OpenGL matrix(1D) in the Source? >> >> >> Regards >> Sajjad >> >> _______________________________________________ >> osg-users mailing list >> [email protected] >> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >> >> > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
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