I'm not sure. gluLookAt was written a decade ago because linux could not call any api with more than 8 double parameters. It was ported to J8 two years ago.
Opengl matrix in J8 should be row-order and pre-multiplication. I cannot recall how I checked the implementation. Пн, 06 апр 2015, Jim Uhl написал(а): > JVERSION > Engine: j803/2014-10-19-11:11:11 > Library: 8.03.13 > Qt IDE: 1.3.1/4.8.2 > Platform: Linux 32 > Installer: J803 install > InstallPath: /home/juhl/j803 > > api/gles version 1.0.21 > -- > The current header of gl_Ortho: > gl_Ortho=: 3 : 0 > looks like it should be: > gl_Ortho=: (gl_I'')&$: : (4 : 0) > The suggested change makes it match gl_Frustum > and allows it to be used both dyadically and monadically. > The original verb fails because it refers to x. > > After much puzzling, I think glu_LookAt may be broken > - the following version matches my understanding > of how this verb should behave, based on the > gluLookAt function in OpenGL: > > glu_LookAt=: 3 : 0 > 'eye center up'=. _3]\,>y > F=. center - eye > f=. (% +/&.:*:)F > UPP=. (% +/&.:*:)up > s=. f ((1&|.@:[ * _1&|.@:]) - _1&|.@:[ * 1&|.@:]) UPP > u=. s ((1&|.@:[ * _1&|.@:]) - _1&|.@:[ * 1&|.@:]) f > M=. |:_4]\ s, 0, u, 0, (-f), 0 0 0 0 1 > M (+/ . *)~ gl_Translate -eye > ) > > In this revised version, eye and center are > points specified in world coordinates, and up > is a vector in world coordinates that will > be aligned to the positive y-axis in the viewing > coordinate system. My apologies if this is not > correct - I'm still trying to make sense of the > OpenGL ES viewing pipeline and J's binding to it. > The existing shader demo still works with this > version, and several small test scripts I've > written generate appropriate images as well. > > Thanks, > > Jim Uhl > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm -- regards, ==================================================== GPG key 1024D/4434BAB3 2008-08-24 gpg --keyserver subkeys.pgp.net --recv-keys 4434BAB3 gpg --keyserver subkeys.pgp.net --armor --export 4434BAB3 ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
