Regarding rendering of parts
2013-04-08, 13:39 (This post was last modified: 2013-04-13, 17:56 by Paul Griffin.)
2013-04-08, 13:39 (This post was last modified: 2013-04-13, 17:56 by Paul Griffin.)
I am trying to write a renderer and so trying to understand the document http://www.ldraw.org/article/415.html.
My first question is does a reverse matrix (determinant < 0) perform a mirroring on the part as I have seen in some places or just changes the winding as the document suggests. I wish the pseudocode at the bottom of the document also included the negative determinant part of the drawing process.
Also regarding rendering. If I open the subpart box5.dat in ldview the backfacing polygons are not rendered. But If I create a file sample.dat and in it I put the line "1 16 0 0 0 1 0 0 0 1 0 0 0 1 box5.dat" and open sample.dat in ldview then the backfacing polygons are rendered. From reading the above document I do not understand why that is the case.
Thank you for any help.
My first question is does a reverse matrix (determinant < 0) perform a mirroring on the part as I have seen in some places or just changes the winding as the document suggests. I wish the pseudocode at the bottom of the document also included the negative determinant part of the drawing process.
Also regarding rendering. If I open the subpart box5.dat in ldview the backfacing polygons are not rendered. But If I create a file sample.dat and in it I put the line "1 16 0 0 0 1 0 0 0 1 0 0 0 1 box5.dat" and open sample.dat in ldview then the backfacing polygons are rendered. From reading the above document I do not understand why that is the case.
Thank you for any help.
-- Saki