GLFW backend fails on macOS: missing glfwMakeContextCurrent() before GLEW initialization

[ShugoSUWAZONO]

I tried installing PDL::Graphics::TriD and failed to see demo. Claude.ai helped me to workaround as follows, I hope helps communitiy:

Environment

• macOS Sequoia (Intel Mac mini)
• Perl 5.42.1 (Homebrew)
• PDL::Graphics::TriD 2.102
• OpenGL::Modern 0.0404
• freeglut 3.8.0 (Homebrew)

Problem

Running demo 3d in pdl2 crashes with:

Error: Missing GL version at .../PDL/Graphics/TriD/GL.pm line 499

The error string "Missing GL version" originates from
OpenGL::Modern's GLEW initialization code (glew.c).

Root Cause

In lib/PDL/Graphics/TriD/GL/GLFW.pm, after glfwCreateWindow() is
called, there is no call to glfwMakeContextCurrent() before GLEW
attempts to retrieve the GL version. GLEW requires an active OpenGL
context to initialize correctly. On macOS, unlike some Linux
configurations, OpenGL contexts are never implicitly made current, so
glewInit() fails immediately.

The fix should be to add:

glfwMakeContextCurrent($glfwin);

immediately after the glfwCreateWindow() call (around line 21 of
GLFW.pm).

Workaround

Setting the environment variable before launching pdl2 works around
the issue by switching to the GLUT backend:

export POGL_WINDOW_TYPE=glut

Notes

The GLUT backend works correctly on this system.

[mohawk2]

Hi Shugo,

Thank you for the report! Please could you try the latest git master? This is an issue I'm aware of and fixed, but haven't released yet as I'm making a few final changes.

[ShugoSUWAZONO]

Thanks a lot for this quick response! The latest git master version of PDL::Graphics::TriD solved the problem. demo 3d now works correctly on macOS Sequoia.

[mohawk2]

Thank you for the quick feedback! Can you comment on whether things seem better or worse with the latest? It's now using GL 3.3 idioms (shaders etc) rather than GL 1.0, and it would be great to have feedback.

[ShugoSUWAZONO]

As for the quality of the latest, I would prefer the previous shading

[mohawk2]

Yes, that was changed deliberately by changing the call to trigrid3d, but that's more or less an aesthetic choice.

Do you find it feels smoother when examining larger datasets? (and are there any changes in the look/feel of those?)

[ShugoSUWAZONO]

$pwd
$HOME/pdl2103 ## trying to use the cpan version
$ cpanm --local-lib=$HOME/pdl2103 local::lib
$ eval $(perl -I ~/pdl2103/lib/perl5 -Mlocal::lib=$HOME/pdl2103)
$ cpanm --reinstall PDL

I compared 2 versions with the following script (on pdl2 shell)

use PDL::Graphics::TriD;
$size = 1000;
my $x2 = (sequence($size,$size) / $size) * 2 * 3.14159;
my $y2 = ($x2->transpose);
my $z2 = sin($x2) * cos($y2) + sin(2*$x2)/2;
my $r = ($z2 - $z2->min) / ($z2->max - $z2->min);
my $g = 1 - $r;
my $b = sin($r * 3.14159);
my $rgb = cat($r, $g, $b)->mv(2,0);
imag3d [$z2], {Lines=>0};

Left side of the attached figure is made with the git master, the right side is made with the distributed version on cpan.
The smoothness while mouse drag is definitely better with the git master in terms of user experience.
I do not know which is better for shading/color. I hope this helps... any better comparison??

[mohawk2]

Thank you for your further investigation! The smooth, indistinguishable look in both is a bit hard to make sense of in both, though the new one on the left might be slightly better. They both remind me of the "mountain range" item in demo 3dgal.

I'd be interested to see if the script looks better with either or both of removing {Lines=>0}, since the lines might help, and especially providing $rgb as a parameter, since your script goes to all the trouble of calculating it :-)

Most of all, I'm glad that the latest feels a bit smoother, since that was my hope and major motivator to go through that.

[ShugoSUWAZONO]

In case of $size=1000, I can hardly see the output images, so I reduced to 500 for both (maximum texture size supported by OpenGL may be 512 or around for intel mac... ??). The final command was imag3d [$z2] (without {Lines=>0} ). The smoothness while dragging is almost same for both (I cannot tell if it is caused by reducing 1000 to 500, or removing {Lines=>0}.
Any other experiment(s) you want to try?

[mohawk2]

Maximum texture sizes tend to be 16384 these days. That is unlikely to be a limiting factor here. But you do raise a good point - lines shouldn't be on/off, but instead be a number to draw one line per n coordinates.

Have you tried imag3d [$z2], [$rgb]?