Manipulating 3D Objects with Perl

April 2024

Workflow

Edit the POV-Ray scene
Render...
- Fix errors in the scene file
- Rinse and repeat...
Improve the design
Rinse and repeat...

This sucks. I want a GUI.

Candidates

Moray: a POV-Ray modeler, apparently withered away
Blender: Great, but exports meshes for everything
OpenSCAD: Good for constructing, but no match for POV-Ray rendering quality

Can I do it in Perl?

Perl GUI Toolkits

In the past, I had used Tk, Gtk, Qt, and Wx
Some are a pain (or impossible) to build or don't work on Windows
...so it's not as TIMTOWTDI as one would think
Good ol' Tk just works
Big thanks to Slaven Rezić for keeping Tk alive!

Can we do ... faster?

Tk is ... a bit slow for thousands of polygons.

Time to learn something new.

OpenGL

"The Industry's Foundation for High Performance Graphics"

I learned it from an online version of "The Official Guide to Learning OpenGL, Version 1.1" (1998)

I could easily translate the examples from C to Perl's OpenGL module (which says it supports version 1.2) 👍

...but the guide is no longer online 😢

OpenGL

...is about to be superseded by Vulkan

"Vulkan is a cross-platform industry standard enabling developers to target a wide range of devices with the same graphics API."

...for which there are no Perl bindings (yet)

Edited to add: ChatGPT says "Writing a Perl XS binding for the Vulkan graphics API would be quite an involved task,..."

So let's stick with what we have

Prima

...is a GUI toolkit which can be built and works on Linux and Windows (and Mac/OSX)

...Dmitry Karasik is an active maintainer (e.g. 5 releases in 2023) 👍

...and it allows use of OpenGL in a widget 👍

A Viewer

In the early days of the web, with 256-color images, Netscape used a universal palette. This rendering of the "Netscape color cube" has more than 100000 polygons.

On my PC at home this renders in 5 milliseconds.

Persisting a Scene

Unimplemented.

3D file formats

...don't look too attractive.

Wavefront OBJ and other binary formats: I want text!
POV-Ray Scene Description Language: too powerful!
I can't write a parser for POV-Ray SDL
Extensible 3D (X3D): XML isn't actually meant for humans to write nor read
X3DOM is a candidate for import/export

Or...

Serialize and store the Perl scene object: Storable and friends to the rescue!

Or maybe not?

Modern Times

The code uses Object::Pad and Feature::Compat::Class (Perl 5.38 classes)
One can not bless arbitrary data structures into these modules' classes
→ makes loading a scene difficult

But also...