forked from bartvdbraak/blender
Added a 2d convex hull function to BPyMathutils
Added a 2D Line intersection function Added a function to BPyMesh that gets the mesh space vertex location of a Faces UV Pixel.
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Campbell Barton
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e47719d253
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98b2e98c79
@ -121,3 +121,148 @@ def genrand():
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return ( float(y) / 0xffffffffL ) # reals
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#------ Mersenne Twister -- end
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""" 2d convexhull
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Based from Dinu C. Gherman's work,
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modified for Blender/Mathutils by Campell Barton
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"""
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######################################################################
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# Public interface
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######################################################################
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from Blender.Mathutils import DotVecs
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def convexHull(point_list_2d):
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"""Calculate the convex hull of a set of vectors
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The vectors can be 3 or 4d but only the Xand Y are used.
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returns a list of convex hull indicies to the given point list
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"""
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######################################################################
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# Helpers
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######################################################################
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def _myDet(p, q, r):
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"""Calc. determinant of a special matrix with three 2D points.
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The sign, "-" or "+", determines the side, right or left,
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respectivly, on which the point r lies, when measured against
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a directed vector from p to q.
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"""
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return (q.x*r.y + p.x*q.y + r.x*p.y) - (q.x*p.y + r.x*q.y + p.x*r.y)
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def _isRightTurn((p, q, r)):
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"Do the vectors pq:qr form a right turn, or not?"
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#assert p[0] != q[0] and q[0] != r[0] and p[0] != r[0]
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if _myDet(p[0], q[0], r[0]) < 0:
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return 1
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else:
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return 0
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# Get a local list copy of the points and sort them lexically.
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points = [(p, i) for i, p in enumerate(point_list_2d)]
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points.sort(lambda a,b: cmp((a[0].x, a[0].y), (b[0].x, b[0].y)))
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# Build upper half of the hull.
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upper = [points[0], points[1]] # cant remove these.
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for i in xrange(len(points)-2):
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upper.append(points[i+2])
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while len(upper) > 2 and not _isRightTurn(upper[-3:]):
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del upper[-2]
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# Build lower half of the hull.
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points.reverse()
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lower = [points.pop(0), points.pop(1)]
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for p in points:
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lower.append(p)
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while len(lower) > 2 and not _isRightTurn(lower[-3:]):
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del lower[-2]
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# Concatenate both halfs and return.
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return [p[1] for ls in (upper, lower) for p in ls]
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def lineIntersect2D(v1a, v1b, v2a, v2b):
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'''
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Do 2 lines intersect, if so where.
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If there is an error, the retured X value will be None
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the y will be an error code- usefull when debugging.
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the first line is (v1a, v1b)
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the second is (v2a, v2b)
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by Campbell Barton
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This function accounts for all known cases of 2 lines ;)
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'''
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x1,y1= v1a.x, v1a.y
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x2,y2= v1b.x, v1b.y
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_x1,_y1= v2a.x, v2a.y
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_x2,_y2= v2b.x, v2b.y
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# Bounding box intersection first.
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if min(x1, x2) > max(_x1, _x2) or \
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max(x1, x2) < min(_x1, _x2) or \
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min(y1, y2) > max(_y1, _y2) or \
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max(y1, y2) < min(_y1, _y2):
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return None, 100 # Basic Bounds intersection TEST returns false.
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# are either of the segments points? Check Seg1
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if abs(x1 - x2) + abs(y1 - y2) <= SMALL_NUM:
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return None, 101
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# are either of the segments points? Check Seg2
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if abs(_x1 - _x2) + abs(_y1 - _y2) <= SMALL_NUM:
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return None, 102
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# Make sure the HOZ/Vert Line Comes first.
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if abs(_x1 - _x2) < SMALL_NUM or abs(_y1 - _y2) < SMALL_NUM:
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x1, x2, y1, y2, _x1, _x2, _y1, _y2 = _x1, _x2, _y1, _y2, x1, x2, y1, y2
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if abs(x2-x1) < SMALL_NUM: # VERTICLE LINE
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if abs(_x2-_x1) < SMALL_NUM: # VERTICLE LINE SEG2
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return None, 111 # 2 verticle lines dont intersect.
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elif abs(_y2-_y1) < SMALL_NUM:
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return x1, _y1 # X of vert, Y of hoz. no calculation.
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yi = ((_y1 / abs(_x1 - _x2)) * abs(_x2 - x1)) + ((_y2 / abs(_x1 - _x2)) * abs(_x1 - x1))
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if yi > max(y1, y2): # New point above seg1's vert line
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return None, 112
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elif yi < min(y1, y2): # New point below seg1's vert line
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return None, 113
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return x1, yi # Intersecting.
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if abs(y2-y1) < SMALL_NUM: # HOZ LINE
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if abs(_y2-_y1) < SMALL_NUM: # HOZ LINE SEG2
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return None, 121 # 2 hoz lines dont intersect.
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# Can skip vert line check for seg 2 since its covered above.
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xi = ((_x1 / abs(_y1 - _y2)) * abs(_y2 - y1)) + ((_x2 / abs(_y1 - _y2)) * abs(_y1 - y1))
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if xi > max(x1, x2): # New point right of seg1's hoz line
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return None, 112
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elif xi < min(x1, x2): # New point left of seg1's hoz line
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return None, 113
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return xi, y1 # Intersecting.
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# Accounted for hoz/vert lines. Go on with both anglular.
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b1 = (y2-y1)/(x2-x1)
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b2 = (_y2-_y1)/(_x2-_x1)
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a1 = y1-b1*x1
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a2 = _y1-b2*_x1
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if b1 - b2 == 0.0:
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return None, 200
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xi = - (a1-a2)/(b1-b2)
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yi = a1+b1*xi
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if (x1-xi)*(xi-x2) >= 0 and (_x1-xi)*(xi-_x2) >= 0 and (y1-yi)*(yi-y2) >= 0 and (_y1-yi)*(yi-_y2)>=0:
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return xi, yi
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else:
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return None, 300
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@ -190,6 +190,54 @@ def getMeshFromObject(ob, container_mesh=None, apply_modifiers=True, vgroups=Tru
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return mesh
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#============================================================================#
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# Takes a face, and a pixel x/y on the image and returns a worldspace x/y/z #
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# will return none if the pixel is not inside the faces UV #
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#============================================================================#
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def getUvPixelLoc(face, pxLoc, img_size = None, uvArea = None):
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TriangleArea= Blender.Mathutils.TriangleArea
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Vector= Blender.Mathutils.Vector
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if not img_size:
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w,h = face.image.size
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else:
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w,h= img_size
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scaled_uvs= [Vector(uv.x*w, uv.y*h) for uv in f.uv]
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if len(scaled_uvs)==3:
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indicies= ((0,1,2),)
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else:
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indicies= ((0,1,2), (0,2,3))
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for fidxs in indicies:
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for i1,i2,i3 in fidxs:
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# IS a point inside our triangle?
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# UVArea could be cached?
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uv_area = TriangleArea(scaled_uvs[i1], scaled_uvs[i2], scaled_uvs[i3])
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area0 = TriangleArea(pxLoc, scaled_uvs[i2], scaled_uvs[i3])
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area1 = TriangleArea(pxLoc, scaled_uvs[i1], scaled_uvs[i3])
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area2 = TriangleArea(pxLoc, scaled_uvs[i1], scaled_uvs[i2])
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if area0 + area1 + area2 > uv_area + 1: # 1 px bleed/error margin.
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pass # if were a quad the other side may contain the pixel so keep looking.
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else:
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# We know the point is in the tri
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area0 /= uv_area
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area1 /= uv_area
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area2 /= uv_area
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# New location
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return Vector(\
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face.v[i1].co[0]*area0 + face.v[i2].co[0]*area1 + face.v[i3].co[0]*area2,\
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face.v[i1].co[1]*area0 + face.v[i2].co[1]*area1 + face.v[i3].co[1]*area2,\
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face.v[i1].co[2]*area0 + face.v[i2].co[2]*area1 + face.v[i3].co[2]*area2\
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)
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return None
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type_tuple= type( (0,) )
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type_list= type( [] )
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def ngon(from_data, indices):
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@ -230,8 +278,7 @@ def ngon(from_data, indices):
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oldmode = Mesh.Mode()
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Mesh.Mode(Mesh.SelectModes['VERTEX'])
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for v in temp_mesh.verts:
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v.sel= 1
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temp_mesh.sel= True # Select all verst
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# Must link to scene
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scn= Scene.GetCurrent()
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