[Soc-2008-dev] Week 7 report

[Maxime Curioni]

Week 7

======


This week

---------

The first part of my week, I tried to make FBO-based offscreen rendering
work in Blender's pipeline, both rendering to a renderbuffer or to a
texture. I was able make rendering to texture work under a custom GLUT
sample program, but when I transpose the same code in Blender, it somehow
produces garbage (
http://maximecurioni.com/gsoc2008/wp-content/uploads/2008/07/2008_07_08_render_error_2.png)
and even corrupts the current back buffer. I have tried many different
tutorials and I have tweaked with about every little detail, from the order
the commands are sent to the different buffer internal formats. I am
supposing that this is caused by GHOST. Having wasted enough time on it, I
have decided to stop trying to implement this temporary feature: as strokes
will eventually be rasterized without OpenGL, this is not a long term
handicap.


I also worked on removing the SWIG dependency from the project.  I studied
the Python/C API in more detail and I learned how SWIG does most of its
magic internally. I now understand how to incorporate the Freestyle Python
API at the lower level. These past two days, I have worked  on redefining
the Freestyle API to make it easy to use: from about 150 original classes
that I would have needed to port, I only have about 30 to implement using
the Python/C API; I'll implement the rest directly in Python (SWIG also
works this way). These 30 classes represent the bare essentials to link up
the Python environment with the internal view map data structures. The API
will reuse Blender's current submodules (for example utilizing
Mathutils.Vector to represent Vec2f, Vec3f, Vec3d structures....). Iterators
will be removed to have list-based traversal and all unnecessary class
casting functions will be removed.


Next week

---------

It's hard to estimate how long it is going to take to replace SWIG totally.
I have implemented 5 classes today and I'll continue this week-end. Once
this is done, even though I was supposed to work on removing lib3ds next, I
want to concentrate my efforts on the OpenGL layer replacement. This is a
major priority for the success of the project.


Issues

------

The main issue I faced was using render buffers under GHOST. I haven't been
able to get it working.



Schedule

--------

I am a week behind schedule. Frankly, I wasted a lot of time trying to make
render buffers work. Looking back, that was not worth it at all. Jean-Luc
and I are going to rework the project schedule this week-end. The last part
of the project (providing visual tools to control the view map) may be
affected.
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