Fooling around with FreeCAD Source and OCC

[fosselius]

This thread will be a place where i dump information about things i find while looking at open cascade visualization and how 3d views are currently rendered.

Initially I played around a bit with QT/open cascade visualization. I have created this fork of a OCC/QT project to be used as a sandbox:
https://github.com/maidenone/occQt

I have briefly gone through this documentation:
https://dev.opencascade.org/doc/overvie ... ation.html

I have also spent way to much time trying to generate dependency graphs of the FreeCAD code base..

I used: https://www.flourish.org/cinclude2dot/ to generate the dot file of all "#include" dependencies between all files, some reference errors where reported, so this is not complete. I configured it to merge "file.c" and "file.h" into "file" to reduce the complexity. It still took more then an hour to render the SVG. I found that viewing with eog (image viewer) is better then google-chrome due to zoom limit..
Still way to complex to follow the lines, but it looks cool.

dependency.png (649.63 KiB) Viewed 1966 times

Fullsize (~12Mb) https://drive.google.com/file/d/1yyGnzd ... sp=sharing

I also tried https://github.com/tomtom-international ... pendencies and got this:
https://drive.google.com/file/d/1eE-r6e ... sp=sharing
https://drive.google.com/file/d/1YKMFTs ... sp=sharing
But those are not detailed enough for me. maybe i misconfigured it..

[fosselius]

I found that Quarter is the Coin3D -> QT library that i should start looking at in the FreeCAD code, extracting a subset from dependency graph above with:

Code: Select all

head source.dot  -n 7 > test.dot
cat source.dot | grep Quarter >> test.dot
echo "}"  >> test.dot 
neato -Tpng test.dot -o test.png

Results in the following graph:

test.png (137.72 KiB) Viewed 1937 times

Where QuaterWidget is the widget where 3d graphics is rendered.
From Quater.cpp:

Quarter is a light-weight glue library that provides seamless
integration between Systems in Motions's \COIN high-level 3D
visualization library and Trolltech's \QT 2D user interface
library.

\QT and \COIN is a perfect match since they are both open source,
widely portable and easy to use. Quarter has evolved from Systems in
Motion's own experiences using \COIN and \QT together in our
applications.

The functionality in Quarter revolves around QuarterWidget, a
subclass of QGLWidget. This widget provides functionality for
rendering of Coin scenegraphs and translation of QEvents into
SoEvents. Using this widget is as easy as using any other QWidget.

Now, part of the code we are interested in are named Inventor, lets add that to our grep:

Code: Select all

<same as above>
cat source.dot | grep -E 'Inventor|Quarter' >> test2.dot
<same as above>
 neato -Tpng -Goverlap=false -Gsplines=true test2.dot -o test2.png

Now this is more in line with what i expected:

test2.png (201.27 KiB) Viewed 1922 times

test2.svg

(192.02 KiB) Downloaded 53 times

Summery of today's activities:
checked out FreeCAD code, installed dependancies and built (QT4, Py2, OCE....)
downloaded OCC and compiled
generated graphs
read OCC documentation
started reading through Quarter code / integration
forked https://github.com/eryar/occQt, resolved build issues, (built for QT5, OCC) started playing with event handler.

[ezzieyguywuf]

Not sure if you're aware, but if you `make DevDoc` in the freecad build directory, it will generate the Doxygen documentation which includes dependency graphs for the various freecad components. This has been helpful for me in terms of seem how the code is structured.

Mod/Part/App/TopoShape.cpp is a decent place to start.

[fosselius]

yes i know, but i wanted an overview, doxygen dependancy graphs is great for the local scope.
my goal is to identify every source/header file that have dependency on coin3d (including pivy for python), so the scope is quite big...

Mod/Part/App/TopoShape.cpp is a decent place to start.

thank you, I will take a closer look tomorrow, any input is greatly valued.

toposhape.png (222.68 KiB) Viewed 1870 times

toposhape.svg

(87.59 KiB) Downloaded 46 times

Here is the DevDoc i built today:
http://foss.site:8080/fc/da/da1/TopoShape_8h.html
compared to:
https://www.freecadweb.org/api/d8/ded/c ... Shape.html (how is this documentation generated?)

[ezzieyguywuf]

since your interest in more on the Coin3d stuff, I would instead start at Mod/Part/Gui/ViewProvider. h, which describes how a Part:Toposhape is rendered using Coin3d.

[vocx]

...
https://www.freecadweb.org/api/d8/ded/c ... Shape.html (how is this documentation generated?)

I just stumbled onto this. The web documentation is a reduced version of the full documentation.

Code: Select all

make DevDoc # full, around 5GB
make WebDoc # reduced, around 0.6 GB

[Kunda1]

Forgot about this cool thread. Very cool. need to bookmark this.

[fosselius]

haha, Typically me, starting a project then changing focus within 10 minutes only to forget what i was doing a week later..

[Kunda1]

haha, Typically me, starting a project then changing focus within 10 minutes only to forget what i was doing a week later..

This
(I can relate)