This commit is an attempt to address degenerate triangles (i.e.,
triangles whose area is zero) that cause incorrect line visibility in
Freestyle.
There are two forms of degenerate triangles. Let A, B and P denote
the three vertices of a triangle. A degenerate triangle is a triangle
such that 1) A and B are in the same position in the 3D space, or
2) the distance between point P and line segment AB is zero. Note
that the first form is a special case of the second form. Degenerate
triangles in the first form is easy to remove by the Remove Doubles
command. This commit is intended to address those degenerate triangles
in the second form.
The implemented fix cannot address degenerate triangles in general.
It fails when a triangle touches with multiple degenerate triangles.
A more general solution needs to be implemented.
New "face marks" and "edge marks" have been introduced in mesh data
blocks. In the edit mode of a mesh object, face marks can be put
to selected faces by choosing Mesh >> Faces >> Mark Freestyle Face
from the menu of a 3D View window or Ctrl-F >> Mark Freestyle Face
from the context menu. Similarly, edge marks can be put to selected
edges by Mesh >> Edges >> Mark Freestyle Edge or Ctrl-E >> Mark
Freestyle Edge. These marks should work fine with the Subdivision
surface modifier.
Moreover, two new conditions for feature edge selection have been
added to the Parameter Editor mode as described below:
1. The Selection by Edge Types option has now the new Edge Mark type,
which can be used to (de)select feature edges having edge marks.
This option can be used to add to (or remove from) the view map
arbitrary edges of mesh objects.
2. Selection by Face Marks option has been newly introduced, in which
face marks are used for feature edge selection in two ways. One
option is called "One Face" which is to (de)select feature edges if
one of faces on the left and right of each feature edge has a face
mark. The other option is "Both Faces" to (de)select feature edges
if both faces on the left and right have a face mark.
the R_TRANSFORMED flag enabled. Now vertex normals are properly
transformed by ObjectInstanceRen::nmat[3][3] and normalized. It is
noted that in the case of R_TRANSFORMED flat faces, surface normals
are transformed and normalized by RE_vlakren_get_normal().
The bug was reported by Stéphane Grabli via personal communication.
Thank you Stéphane for the careful code review!
With this option disabled, the smoothness of faces is ignored and
jagged feature edges (when seen from a three-dimensional viewpoint)
are generated. If the new option is enabled, face smoothness is taken
into account during the view map calculation, resulting in smooth
feature edges in 3D. This generally leads to more stable strokes, and
also permits more stylization possibilities relying on the feature
edge smoothness in 3D. The downside of smooth feature edges is that
the visibility is mathematically not well-defined and may cause some
artefact in rendering results. The new option is thus intended to
allow users to try both jagged and smooth feature edges and see which
ones would fit individual application needs. This option is disabled
by default.
ViewShape objects in the view map, as well as SShape objects
that can be retrieved with ViewShape::sshape(), now have a
getName() method that returns the name of the object from
which each shape is created. For instance, visible feature
edges of specific mesh objects (e.g., Cube.001 and Cube.002)
can be selected using custom predicate ObjectNamesUP1D as
follows:
class ObjectNamesUP1D(UnaryPredicate1D):
def __init__(self, names):
UnaryPredicate1D.__init__(self)
self._names = names
def getName(self):
return "ObjectNamesUP1D"
def __call__(self, viewEdge):
return viewEdge.viewShape().getName() in self._names
upred = AndUP1D(QuantitativeInvisibilityUP1D(0),
ObjectNamesUP1D(["Cube.001", "Cube.002"]))
Operators.select(upred)
Previously mesh vertices imported from vlak nodes were transformed
from the camera coordinate system to the object local coordinate
system. This causes a difficulty in recovering object local vertices
when mesh deforming modifiers (e.g., curve, cloth, and soft body) have
been applied. Now the view map creation is done based on mesh
vertices in the camera coordinate system. Advantages of this approach
includes: 1) faster mesh importing because of less matrix-based
transformations; and 2) proper handling of meshes with deforming
modifiers.
A straightforward clipping algorithm was implemented to
eliminate vertices that are out of the interval from the
near to far clipping distance defined by the active camera.
Previously, objects that come behind the camera could lead
to a crash. The changes in this commit is intended to
address this issue. When meshes are partially clipped, new
edges are added. These edges can result in visible strokes
if they are within the camera view.
instability issues regarding the view map creation. A new iterative
solver of the 2D-to-3D inverse projection transformation problem was
implemented. Instead of directly solving the problem in the direction
from the 2D to 3D space, the new solver starts with an initial guess of
an approximated solution and asymptotically approaches to the true
solution by iteratively performing the forward 3D-to-2D projection
transformation and improving the approximation. Preliminary tests with
one simple and another complex scenes showed that the solver converges
quickly (more and less 20 iterations in many cases, with a stopping
criterion of a residual distance between the true and approximated
solutions less than 1e-6 Blender Unit).
The following files were according to the Math Lib reorganization
(see the commit log of revision 24464 for more information):
source/blender/freestyle/intern/blender_interface/BlenderFileLoader.cpp
source/blender/freestyle/intern/blender_interface/BlenderFileLoader.h
The file release/scripts/ui/properties_render.py was also updated
according the RNA UI API renaming in revision 24795.
