Many parts of the compositor are unnecessarily complicated. This patch
aims at reducing the complexity of writing nodes and making the code
more transparent.
== Separating Nodes and Operations ==
Currently these are both mixed in the same graph, even though they have
very different purposes and are used at distinct stages in the
compositing process. The patch introduces dedicated graph classes for
nodes and for operations.
This removes the need for a lot of special case checks (isOperation etc.)
and explicit type casts. It simplifies the code since it becomes clear
at every stage what type of node we are dealing with. The compiler can
use static typing to avoid common bugs from mixing up these types and
fewer runtime sanity checks are needed.
== Simplified Node Conversion ==
Converting nodes to operations was previously based on "relinking", i.e.
nodes would start with by mirroring links in the Blender DNA node trees,
then add operations and redirect these links to them. This was very hard
to follow in many cases and required a lot of attention to avoid invalid
states.
Now there is a helper class called the NodeConverter, which is passed to
nodes and implements a much simpler API for this process. Nodes can add
operations and explicit connections as before, but defining "external"
links to the inputs/outputs of the original node now uses mapping
instead of directly modifying link data. Input data (node graph) and
result (operations graph) are cleanly separated.
== Removed Redundant Data Structures ==
A few redundant data structures have been removed, notably the
SocketConnection. These are only needed temporarily during graph
construction. For executing the compositor operations it is perfectly
sufficient to store only the direct input link pointers. A common
pointer indirection is avoided this way (which might also give a little
performance improvement).
== Avoid virtual recursive functions ==
Recursive virtual functions are evil. They are very hard to follow
during debugging. At least in the parts this patch is concerned with
these functions have been replaced by a non-virtual recursive core
function (which might then call virtual non-recursive functions if
needed). See for example NodeOperationBuilder::group_operations.
EWA sampling is designed for downsampling images, i.e. scaling down the size of
input image pixels, which happens regularly in compositing. While the standard
sampling methods (linear, cubic) work reasonably well for linear
transformations, they don't yield good results in non-linear cases like
perspective projection or arbitrary displacement. EWA sampling is comparable to
mipmapping, but avoids problems with discontinuities.
To work correctly the EWA algorithm needs partial derivatives of the mapping
functions which convert output pixel coordinates back into the input image
space (2x2 Jacobian matrix). With these derivatives the EWA algorithm
projects ellipses into the input space and accumulates colors over their
area. This calculation was not done correctly in the compositor, only the
derivatives du/dx and dv/dy were calculation, basically this means it only
worked for non-rotated input images.
The patch introduces full derivative calculations du/dx, du/dy, dv/dx, dv/dy for
the 3 nodes which use EWA sampling currently: PlaneTrackWarp, MapUV and
Displace. In addition the calculation of ellipsis area and axis-aligned
bounding boxes has been fixed.
For the MapUV and Displace nodes the derivatives have to be estimated by
evaluating the UV/displacement inputs with 1-pixel offsets, which can still have
problems on discontinuities and sub-pixel variations. These potential problems
can only be alleviated by more radical design changes in the compositor
functions, which are out of scope for now. Basically the values passed to the
UV/Displacement inputs would need to be associated with their 1st order
derivatives, which requires a general approach to derivatives in all nodes.
- add missing headers from cmake (own omission)
- quiet rna_test.c unused define warnings.
- minor style edits
- spelling corrections and ignore all uppercase words with spell checking script.
re-optimized the Defocus node.
* localized MemoryBuffers
* removed read(x,y) calls
* shuffled some lines in the execute pixel
* added a readNoCheck function to the memorybuffer (only use this when
you are certain you are reading a pixel inside the memorybuffer.
`````|````` | | | ..''''
| | | |______ .''
| | | | ..'
| | |_______ |___________ ....''
merge to TRUNK!
* The old compositor is still available (Debug Menu: 200)
This commit was brought to you by:
Developers:
* Monique Dewanchand
* Jeroen Bakker
* Dalai Felinto
* Lukas Tönne
Review:
* Brecht van Lommel
Testers:
* Nate Wiebe
* Wolfgang Faehnle
* Carlo Andreacchio
* Daniel Salazar
* Artur Mag
* Christian Krupa
* Francesco Siddi
* Dan McGrath
* Bassam Kurdali
But mostly by the community:
Gold:
Joshua Faulkner
Michael Tiemann
Francesco Paglia
Blender Guru
Blender Developers Fund
Silver:
Pablo Vazquez
Joel Heethaar
Amrein Olivier
Ilias Karasavvidis
Thomas Kumlehn
Sebastian Koenig
Hannu Hoffrén
Benjamin Dansie
Fred M'ule
Michel Vilain
Bradley Cathey
Gianmichele Mariani
Gottfried Hofmann
Bjørnar Frøyse
Valentijn Bruning
Paul Holmes
Clemens Rudolph
Juris Graphix
David Strebel
Ronan Zeegers
François Tarlier
Felipe Andres Esquivel Reed
Olaf Beckman
Jesus Alberto Olmos Linares
Kajimba
Maria Figueiredo
Alexandr Galperin
Francesco Siddi
Julio Iglesias Lopez
Kjartan Tysdal
Thomas Torfs
Film Works
Teruyuki Nakamura
Roger Luethi
Benoit Bolsee
Stefan Abrahamsen
Andreas Mattijat
Xavier Bouchoux
Blender 3D Graphics and Animation
Henk Vostermans
Daniel Blanco Delgado
BlenderDay/2011
Bradley Cathey
Matthieu Dupont de Dinechin
Gianmichele Mariani
Jérôme Scaillet
Bronze (Ivo Grigull, Dylan Urquidi, Philippe Derungs, Phil Beauchamp, Bruce Parrott, Mathieu Quiblier, Daniel Martinez, Leandro Inocencio, Lluc Romaní Brasó,
Jonathan Williamson, Michael Ehlen, Karlis Stigis, Dreamsteep, Martin Lindelöf, Filippo Saracino, Douwe van der Veen, Olli Äkräs, Bruno D'Arcangeli,
Francisco Sedrez Warmling, Watchmike.ca, peter lener, Matteo Novellino, Martin Kirsch, Austars Schnore, KC Elliott, Massimiliano Puliero, Karl Stein,
Wood Design Studios, Omer Khan, Jyrki Kanto, Michał Krupa, Lars Brubaker, Neil Richmond, Adam Kalisz, Robert Garlington, Ian Wilson, Carlo Andreacchio,
Jeremias Boos, Robert Holcomb, Gabriel Zöller, Robert Cude, Natibel de Leon, Nathan Turnage, Nicolas Vergnes, Philipp Kleinhenz, Norman Hartig, Louis Kreusel,
Christopher Taylor, Giovanni Remondini, Daniel Rentzsch, Nico Partipilo, Thomas Ventresco, Johannes Schwarz, Александр Коротеев, Brendon Harvey,
Marcelo G. Malheiros, Marius Giurgi, Richard Burns, Perttu Iso-Metsälä, Steve Bazin, Radoslav Borisov, Yoshiyuki Shida, Julien Guigner, Andrew Hunter,
Philipp Oeser, Daniel Thul, Thobias Johansson, Mauro Bonecchi, Georg Piorczynski, Sebastian Michailidis, L M Weedy, Gen X, Stefan Hinze, Nicolò Zubbini,
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Joseph Christie, Victor Hernández García, David Mcsween, James Finnerty, Cory Kruckenberg, Giacomo Graziosi, Olivier Saraja, Lars Brubaker, Eric Hudson,
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