Merge pull request #2545 from nortikin/b28_inset_special_normals

Port " Inset special node: more precise normal calculation" to 2.80

Merge pull request #2545 from nortikin/b28_inset_special_normals
Port " Inset special node: more precise normal calculation" to 2.80
d550a882 · Ilya V. Portnov · GitHub · 57918c61 · f8447b4b · d550a882
--- a/nodes/modifier_make/inset_special.py
+++ b/nodes/modifier_make/inset_special.py
@@ -22,9 +22,10 @@ import bpy
 import mathutils
 from mathutils import Vector
-from bpy.props import FloatProperty, FloatVectorProperty, IntProperty
+from bpy.props import FloatProperty, FloatVectorProperty, IntProperty, EnumProperty
 from sverchok.node_tree import SverchCustomTreeNode
+from sverchok.utils.geom import calc_normal
 from sverchok.data_structure import (
    updateNode, Vector_generate,
    repeat_last, fullList)
@@ -33,7 +34,7 @@ from sverchok.data_structure import (
 ''' very non optimal routines. beware. I know this '''
-def inset_special(vertices, faces, inset_rates, distances, ignores, make_inners):
+def inset_special(vertices, faces, inset_rates, distances, ignores, make_inners, normal_mode="Fast"):
    new_faces = []
    new_ignores = []
@@ -115,7 +116,10 @@ def inset_special(vertices, faces, inset_rates, distances, ignores, make_inners)
        new_verts_prime = [avg_vec.lerp(v, inset_by) for v in verts]
        if distance:
-            local_normal = mathutils.geometry.normal(*new_verts_prime[:3])
+            if normal_mode == 'Fast':
+                local_normal = mathutils.geometry.normal(*new_verts_prime[:3])
+            else:
+                local_normal = calc_normal(new_verts_prime)
            new_verts_prime = [v.lerp(v+local_normal, distance) for v in new_verts_prime]
        vertices.extend(new_verts_prime)
@@ -149,7 +153,12 @@ class SvInsetSpecial(bpy.types.Node, SverchCustomTreeNode):
    bl_label = 'Inset Special'
    bl_icon = 'OUTLINER_OB_EMPTY'
-    inset: FloatProperty(
+    normal_modes = [
+            ("Fast", "Fast", "Fast algorithm", 0),
+            ("Exact", "Exact", "Slower, but exact algorithm", 1)
+        ]
+    inset : FloatProperty(
        name='Inset',
        description='inset amount',
        default=0.1, update=updateNode)
@@ -161,6 +170,12 @@ class SvInsetSpecial(bpy.types.Node, SverchCustomTreeNode):
    ignore: IntProperty(name='Ignore', description='skip polygons', default=0, update=updateNode)
    make_inner: IntProperty(name='Make Inner', description='Make inner polygon', default=1, update=updateNode)
+    normal_mode : EnumProperty(name = "Normals",
+            description = "Normals calculation algorithm",
+            default = "Fast",
+            items = normal_modes,
+            update = updateNode)
    # axis = FloatVectorProperty(
    #   name='axis', description='axis relative to normal',
    #   default=(0,0,1), update=updateNode)
@@ -180,6 +195,8 @@ class SvInsetSpecial(bpy.types.Node, SverchCustomTreeNode):
        o.new('SvStringsSocket', 'ignored')
        o.new('SvStringsSocket', 'inset')
+    def draw_buttons_ext(self, context, layout):
+        layout.prop(self, "normal_mode")
    def process(self):
        i = self.inputs
@@ -221,7 +238,8 @@ class SvInsetSpecial(bpy.types.Node, SverchCustomTreeNode):
                'inset_rates': inset_rates,
                'distances': distance_vals,
                'make_inners': make_inners,
-                'ignores': ignores
+                'ignores': ignores,
+                'normal_mode': self.normal_mode
            }
            res = inset_special(**func_args)

--- a/utils/geom.py
+++ b/utils/geom.py
@@ -907,6 +907,27 @@ def interpolate_quadratic_bezier(knot1, handle, knot2, resolution):
    handle2 = handle + (1.0/3.0) * (knot2 - handle)
    return interpolate_bezier(knot1, handle1, handle2, knot2, resolution)
+def calc_normal(vertices):
+    """
+    Calculate normal for a face defined by specified vertices.
+    For tris or quads, mathutils.geometry.normal() is used.
+    Ngon will be triangulated, and then the average normal of
+    all resulting tris will be returned.
+    input: list of 3-tuples or list of mathutils.Vector.
+    output: mathutils.Vector.
+    """
+    n = len(vertices)
+    vertices = list(map(mathutils.Vector, vertices))
+    if n <= 4:
+        return mathutils.geometry.normal(*vertices)
+    else:
+        # Triangluate
+        triangle_idxs = [[0, k, k+1] for k in range(1, n-1)]
+        triangles = [[vertices[i] for i in idxs] for idxs in triangle_idxs]
+        subnormals = [mathutils.geometry.normal(*triangle) for triangle in triangles]
+        return mathutils.Vector(center(subnormals))
 def multiply_vectors(M, vlist):
    # (4*4 matrix)  X   (3*1 vector)