Differential D319 Diff 1913 release/scripts/freestyle/modules/freestyle/utils.py

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release/scripts/freestyle/modules/freestyle/utils.py

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	integrate,	integrate,
	)	)

	# constructs for definition of helper functions in Python	__all__ = (
	from freestyle.types import (	"get_chain_length",
	StrokeVertexIterator,	"iter_t2d_along_stroke",
		"iter_distance_from_camera",
		"iter_distance_from_object",
		"iter_material_color",
		"iter_material_value",
		"iter_distance_along_stroke",
		"iter_distance_to_neighbors",
	)	)
	import mathutils

		""" helper functions for chaining """

		def get_chain_length(ve, orientation):
		"""
		Returns the 2d length of a given ViewEdge
		"""
		from freestyle.chainingiterators import pyChainSilhouetteGenericIterator
		kjym3Unsubmitted Not Done Inline Actions I guess this helper function needs to be renamed to `chromatize` as referred to in the code below? kjym3: I guess this helper function needs to be renamed to `chromatize` as referred to in the code…
		flokkievidsAuthorUnsubmitted Not Done Inline Actions I'm still unsure about the name. do you have a prefference? flokkievids: I'm still unsure about the name. do you have a prefference?
		kjym3Unsubmitted Not Done Inline Actions I don't really have much preference: rgb_to_grayscale, rgb_to_intensity, chromatize, or whatever makes sense. One option is rgb_to_bw() since the same formula appears in `source/blender/blenlib/intern/math_color_inline.c`. kjym3: I don't really have much preference: rgb_to_grayscale, rgb_to_intensity, chromatize, or…
		flokkievidsAuthorUnsubmitted Not Done Inline Actions took that one flokkievids: took that one
		length = 0.0
		# setup iterator
		_it = pyChainSilhouetteGenericIterator(False, False)
		_it.begin = ve
		_it.current_edge = ve
		_it.orientation = orientation
		_it.init()

		# run iterator till end of chain
		kjym3Unsubmitted Not Done Inline Actions I saw this helper function also in your regression test suite. Do you actually want to include this in the freestyle.utils module? kjym3: I saw this helper function also in your regression test suite. Do you actually want to include…
		flokkievidsAuthorUnsubmitted Not Done Inline Actions I think it's not needed. (pretty nice recipe though) flokkievids: I think it's not needed. (pretty nice recipe though)
		while not (_it.is_end):
		length += _it.object.length_2d
		# _it has looped back to the beginning;
		# break to prevent infinite loop
		if (_it.is_begin):
		break
		_it.increment()

		# reset iterator
		_it.begin = ve
		_it.current_edge = ve
		_it.orientation = orientation

		# run iterator till begin of chain
		if not _it.is_begin:
		_it.decrement()
		while (not _it.is_end) and (not _it.is_begin):
		length += _it.object.length_2d
		_it.decrement()

		return length

		kjym3Unsubmitted Not Done Inline Actions Originally these `iter_` helper functions were returning an iterator and extra object(s), because in the caller side, one might need to call 0D/1D functions which take an Interface0DIterator. It is true that returning a stroke vertex instead of an iterator saves one line of code (i.e., `sv = it.object`), but at the cost of creating an iterator in parallel to the `iter_` loop on the caller side if it is necessary to call 0D/1D functions. To me returning an iterator instead of a stroke vertex seems a way to go since it will help make user code simple and straightforward although the extra line `sv = it.object` might appear clumsy. kjym3: Originally these `iter_` helper functions were returning an iterator and extra object(s)…
		""" helper functions for iterating """

		def iter_t2d_along_stroke(stroke):
		"""
		the distance between two stroke vertices
		relative to the total stroke length.
		"""
		total = stroke.length_2d
		distance = 0.0
		it = iter(stroke)
		prev = stroke[0].point
		for svert in it:
		p = svert.point
		distance += (prev - p).length
		prev = p.copy() # need a copy because the point can be altered
		t = min(distance / total, 1.0) if total > 0.0 else 0.0
		yield svert, t

		def iter_distance_from_camera(stroke, range_min, range_max):
		"""
		yields the distance to the camera relative to the maximum
		possible distance for every stroke vertex, constrained by
		given minimum and maximum values.
		"""
		normfac = range_max - range_min # normalization factor
		for svert in stroke:
		distance = svert.point_3d.length # in the camera coordinate
		if distance < range_min:
		t = 0.0
		elif distance > range_max:
		t = 1.0
		else:
		t = (distance - range_min) / normfac
		yield svert, t

		def iter_distance_from_object(stroke, object, range_min, range_max):
		"""
		yields the distance to the given object relative to the maximum
		possible distance for every stroke vertex, constrained by
		given minimum and maximum values.
		"""
		scene = getCurrentScene()
		mv = scene.camera.matrix_world.copy().inverted() # model-view matrix
		loc = mv * object.location # loc in the camera coordinate
		normfac = range_max - range_min # normalization factor
		it = stroke.stroke_vertices_begin()
		for svert in stroke:
		p = it.object.point_3d # in the camera coordinate
		distance = (p - loc).length
		if distance < range_min:
		t = 0.0
		elif distance > range_max:
		t = 1.0
		else:
		t = (distance - range_min) / normfac
		yield svert, t

		def iter_material_color(stroke, material_attribute):
		"""
		yields the specified material attribute for every stroke vertex.
		the material is taken from the object behind the vertex.
		"""
		func = CurveMaterialF0D()
		it = Interface0DIterator(iter(stroke))
		for svert, inter in zip(stroke, it):
		material = func(it)
		if material_attribute == 'DIFF':
		color = material.diffuse[0:3]
		elif material_attribute == 'SPEC':
		color = material.specular[0:3]
		else:
		raise ValueError("unexpected material attribute: " + material_attribute)
		yield svert, color

		kjym3Unsubmitted Not Done Inline Actions The function name could be `rgb_to_intensity` or `rgb_to_grayscale`. There are many named RGB-to-grayscale conversion methods (see http://en.wikipedia.org/wiki/Grayscale for more info), but the formula used here seems not any of them. I don't remember from where I took it... kjym3: The function name could be `rgb_to_intensity` or `rgb_to_grayscale`. There are many named RGB…

		# this needs a better name
		# what is the name of this method?
		def color_transformation(r, g, b):
		return 0.35 * r + 0.45 * r + 0.2 * b

		def iter_material_value(stroke, material_attribute):
		"""
		yields a specific material attribute
		from the vertex' underlying material.
		"""
		func = CurveMaterialF0D()
		it = Interface0DIterator(iter(stroke))
		for svert, inter in zip(stroke, it):
		material = func(it)
		if material_attribute == 'DIFF':
		r, g, b = material.diffuse[0:3]
		t = 0.35 * r + 0.45 * r + 0.2 * b
		elif material_attribute == 'DIFF_R':
		t = material.diffuse[0]
		elif material_attribute == 'DIFF_G':
		t = material.diffuse[1]
		elif material_attribute == 'DIFF_B':
		t = material.diffuse[2]
		elif material_attribute == 'SPEC':
		r, g, b = material.specular[0:3]
		t = 0.35 * r + 0.45 * r + 0.2 * b
		elif material_attribute == 'SPEC_R':
		t = material.specular[0]
		elif material_attribute == 'SPEC_G':
		t = material.specular[1]
		elif material_attribute == 'SPEC_B':
		t = material.specular[2]
		elif material_attribute == 'SPEC_HARDNESS':
		t = material.shininess
		elif material_attribute == 'ALPHA':
		t = material.diffuse[3]
		else:
		raise ValueError("unexpected material attribute: " + material_attribute)
		yield svert, t

		def iter_distance_along_stroke(stroke):
		"""
		yields the absolute distance between
		the current and preceding vertex.
		"""
		distance = 0.0
		prev = next(iter(stroke))
		for svert in stroke:
		p = svert.point
		distance += (prev - p).length
		prev = p.copy() # need a copy because the point can be altered
		kjym3Unsubmitted Not Done Inline Actions This helper function seems not to work in the way the name suggests, since `prev` and `svert` are not being updated in the for loop. kjym3: This helper function seems not to work in the way the name suggests, since `prev` and `svert`…
		yield svert, distance

		def iter_distance_to_neighbors(stroke):
		"""
		"""
		it = iter(stroke)
		prev = next(it)
		svert = next(it)
		for next in it:
		yield ((svert.point - prev.point).length, (next.point - svert.point).length)

		def iter_triplet(it):
		prev = next(it)
		current = next(it)
		for succ in it:
		yield prev, current, succ
		prev, current = current, succ


		""" mathmatical operations """

		def curvature(stroke):
		"""
		evaluates the curvature at every vertex of the stroke
		K = 1 / R
		where R is the radius of the circle going through the current vertex and its neighbors
		"""
		yield 0.0

		for prev, current, next in iter_triplet(iter(stroke)):
		ab = (current.point - prev.point)
		bc = (next.point - current.point)
		ac = (prev.point - next.point)

		a, b, c = ab.length, bc.length, ac.length

		try:
		area = .5 * (ab.cross(ac))

		R = ((a * b * c) / area) / 4
		# constrain K to range {0, 1}
		K = pow(R, -1)
		K = min(max(K, 0), 1)

		except ZeroDivisionError:
		K = 0
		yield K

		yield 0.0

	def stroke_normal(it):	def stroke_normal(it):
	"""	"""
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	if it.is_begin:	if it.is_begin:
	e = it_next.object.point_2d - it.object.point_2d	e = it_next.object.point_2d - it.object.point_2d
	n = mathutils.Vector((e[1], -e[0]))	n = mathutils.Vector((e[1], -e[0]))
	n.normalize()	return n.normalized()
	return n
	# last stroke segment	# last stroke segment
	it_prev = StrokeVertexIterator(it)	it_prev = StrokeVertexIterator(it)
	it_prev.decrement()	it_prev.decrement()
	if it_next.is_end:	if it_next.is_end:
	e = it.object.point_2d - it_prev.object.point_2d	e = it.object.point_2d - it_prev.object.point_2d
	n = mathutils.Vector((e[1], -e[0]))	n = mathutils.Vector((e[1], -e[0]))
	n.normalize()	return n.normalized()
	return n
	# two subsequent stroke segments	# two subsequent stroke segments
	e1 = it_next.object.point_2d - it.object.point_2d	e1 = it_next.object.point_2d - it.object.point_2d
	e2 = it.object.point_2d - it_prev.object.point_2d	e2 = it.object.point_2d - it_prev.object.point_2d
	n1 = mathutils.Vector((e1[1], -e1[0]))	n1 = mathutils.Vector((e1[1], -e1[0])).normalized()
	n2 = mathutils.Vector((e2[1], -e2[0]))	n2 = mathutils.Vector((e2[1], -e2[0])).normalized()
	n1.normalize()	n = (n1 + n2)
	n2.normalize()	return n.normalized()
	n = n1 + n2
	n.normalize()
	return n
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