mesh_tiny_cad/CCEN.py

   1 # SPDX-License-Identifier: GPL-2.0-or-later
   2
   3
   4 import math
   5
   6 import bpy
   7 import bmesh
   8 import mathutils
   9 from mathutils import geometry
  10 from mathutils import Vector
  11
  12
  13 def generate_bmesh_repr(p1, v1, axis, num_verts):
  14     '''
  15         p1:     center of circle (local coordinates)
  16         v1:     first vertex of circle in (local coordinates)
  17         axis:   orientation matrix
  18         origin: obj.location
  19     '''
  20     props = bpy.context.scene.tinycad_props
  21     rescale = props.rescale
  22
  23     # generate geometry up front
  24     chain = []
  25     gamma = 2 * math.pi / num_verts
  26     for i in range(num_verts + 1):
  27         theta = gamma * i
  28         mat_rot = mathutils.Matrix.Rotation(theta, 4, axis)
  29         local_point = (mat_rot @ ((v1 - p1) * rescale))
  30         chain.append(local_point + p1)
  31
  32     obj = bpy.context.edit_object
  33     me = obj.data
  34     bm = bmesh.from_edit_mesh(me)
  35
  36     # add verts
  37     v_refs = []
  38     for p in chain:
  39         v = bm.verts.new(p)
  40         v.select = False  # this might be a default.. redundant?
  41         v_refs.append(v)
  42
  43     # join verts, daisy chain
  44     num_verts = len(v_refs)
  45     for i in range(num_verts):
  46         idx1 = i
  47         idx2 = (i + 1) % num_verts
  48         bm.edges.new([v_refs[idx1], v_refs[idx2]])
  49
  50     bmesh.update_edit_mesh(me, loop_triangles=True)
  51
  52
  53 def generate_3PT(pts, obj, nv, mode=1):
  54     mw = obj.matrix_world
  55     V = Vector
  56     nv = max(3, nv)
  57
  58     # construction
  59     v1, v2, v3, v4 = V(pts[0]), V(pts[1]), V(pts[1]), V(pts[2])
  60     edge1_mid = v1.lerp(v2, 0.5)
  61     edge2_mid = v3.lerp(v4, 0.5)
  62     axis = geometry.normal(v1, v2, v4)
  63     mat_rot = mathutils.Matrix.Rotation(math.radians(90.0), 4, axis)
  64
  65     # triangle edges
  66     v1_ = ((v1 - edge1_mid) @ mat_rot) + edge1_mid
  67     v2_ = ((v2 - edge1_mid) @ mat_rot) + edge1_mid
  68     v3_ = ((v3 - edge2_mid) @ mat_rot) + edge2_mid
  69     v4_ = ((v4 - edge2_mid) @ mat_rot) + edge2_mid
  70
  71     r = geometry.intersect_line_line(v1_, v2_, v3_, v4_)
  72     if r:
  73         p1, _ = r
  74         cp = mw @ p1
  75         bpy.context.scene.cursor.location = cp
  76
  77         if mode == 0:
  78             pass
  79
  80         elif mode == 1:
  81             generate_bmesh_repr(p1, v1, axis, nv)
  82
  83     else:
  84         print('not on a circle')
  85
  86
  87 def get_three_verts_from_selection(obj):
  88     me = obj.data
  89     bm = bmesh.from_edit_mesh(me)
  90
  91     bm.verts.ensure_lookup_table()
  92     bm.edges.ensure_lookup_table()
  93
  94     return [v.co[:] for v in bm.verts if v.select]
  95
  96
  97 def dispatch(context, mode=0):
  98     try:
  99         obj = context.edit_object
 100         pts = get_three_verts_from_selection(obj)
 101         props = context.scene.tinycad_props
 102         generate_3PT(pts, obj, props.num_verts, mode)
 103     except:
 104         print('dispatch failed', mode)
 105
 106
 107 class TCCallBackCCEN(bpy.types.Operator):
 108     bl_idname = 'tinycad.reset_circlescale'
 109     bl_label = 'CCEN circle reset'
 110     bl_options = {'REGISTER'}
 111
 112     def execute(self, context):
 113         context.scene.tinycad_props.rescale = 1
 114         return {'FINISHED'}
 115
 116
 117 class TCCircleCenter(bpy.types.Operator):
 118     '''Recreate a Circle from 3 selected verts, move 3dcursor to its center'''
 119
 120     bl_idname = 'tinycad.circlecenter'
 121     bl_label = 'CCEN circle center from selected'
 122     bl_options = {'REGISTER', 'UNDO'}
 123
 124     def draw(self, context):
 125         scn = context.scene
 126         l = self.layout
 127         col = l.column()
 128
 129         col.prop(scn.tinycad_props, 'num_verts', text='num verts')
 130         row = col.row(align=True)
 131         row.prop(scn.tinycad_props, 'rescale', text='rescale')
 132         row.operator('tinycad.reset_circlescale', text="", icon="PIVOT_CURSOR")
 133
 134     @classmethod
 135     def poll(cls, context):
 136         obj = context.edit_object
 137         return obj is not None and obj.type == 'MESH'
 138
 139     def execute(self, context):
 140         dispatch(context, mode=1)
 141         return {'FINISHED'}