Made Controller::_EPSILON constant with the value 1e-6. Previously,
the _EPSILON value was computed based on the minimum edge size within
the scene being rendered (in some cases, the computed value resulted
in zero). This does not seem to make sense, because _EPSILON has been
used as a tolerance threshold of floating-point arithmetic errors
throughout the view map creation. Since Blender uses single-precision
real values for mesh data representations, the new constant _EPSILON
value looks more adequate.
The FEdgeXDetector class for silhouette edge detection and the
ViewMapBuilder class for view map creation are enhanced. All changes
are related to view point handling (i.e., the camera location). In
the perspective projection, the visibility of feature edges and edge
types (e.g., borders and crease lines) are computed based on a fixed
view point, whereas the view point in the orthographic projection is
an arbitrary point on the XY plane at the origin and is determined so
that a line segment from the view point to a point in the 3D space is
perpendicular to the XY plane. All view point related portions of the
class definitions were modified so as to deal with the two different
camera modes.
initializing Freestyle and specifying contexts, making the API a bit messy.
Now FRS_initialize() is only for initialization, and contexts are specified
by new FRS_set_context() function just before starting rendering.
