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Preliminar work on arch vector renderer

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Yorik van Havre 2012-03-30 17:34:10 -03:00
parent 7b97498f00
commit 565011f289
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src/Mod/Arch/ArchVRM.py Normal file
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#***************************************************************************
#* *
#* Copyright (c) 2012 *
#* Yorik van Havre <yorik@uncreated.net> *
#* *
#* This program is free software; you can redistribute it and/or modify *
#* it under the terms of the GNU Lesser General Public License (LGPL) *
#* as published by the Free Software Foundation; either version 2 of *
#* the License, or (at your option) any later version. *
#* for detail see the LICENCE text file. *
#* *
#* This program is distributed in the hope that it will be useful, *
#* but WITHOUT ANY WARRANTY; without even the implied warranty of *
#* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
#* GNU Library General Public License for more details. *
#* *
#* You should have received a copy of the GNU Library General Public *
#* License along with this program; if not, write to the Free Software *
#* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 *
#* USA *
#* *
#***************************************************************************
"The FreeCAD Arch Vector Rendering Module"
import FreeCAD,math,Part
from draftlibs import fcvec,fcgeo
DEBUG = True # if we want debug messages
MAXLOOP = 10 # the max number of loop before abort
class Renderer:
"A renderer object"
def __init__(self,wp=None):
"""
Creates a renderer with a default Draft WorkingPlane
Use like this:
import ArchVRM
p = ArchVRM.Renderer()
p.add(App.ActiveDocument.ActiveObject)
p.sort()
p.buildDummy()
"""
self.wp = wp
self.faces = []
self.oriented = False
self.trimmed = False
self.sorted = False
if not self.wp:
import WorkingPlane
self.wp = WorkingPlane.plane()
if DEBUG: print "Renderer initialized on " + str(self.wp)
def __str__(self):
return "Arch Renderer: " + str(len(self.faces)) + " faces projected on " + str(self.wp)
def setWorkingPlane(self,wp):
"sets a Draft WorkingPlane for this renderer"
self.wp = wp
if DEBUG: print "Renderer set on " + str(self.wp)
def add(self,faces):
"add faces, shape or object to this renderer"
if isinstance(faces,list):
f = faces
elif hasattr(faces,"Faces"):
f = faces.Faces
elif hasattr(faces,"Shape"):
f = faces.Shape.Faces
if DEBUG: print "adding ", len(f), " faces"
self.faces.extend(f)
self.oriented = False
self.trimmed = False
self.sorted = False
def clean(self):
"removes all faces from this renderer"
self.faces = []
self.oriented = False
self.trimmed = False
self.sorted = False
def isVisible(self,face):
"returns True if the given face points in the view direction"
normal = face.normalAt(0,0)
if DEBUG: print "checking face normal ", normal, " against ", self.wp.axis, " : ", math.degrees(normal.getAngle(self.wp.axis))
if normal.getAngle(self.wp.axis) < math.pi/2:
return True
return False
def reorient(self):
"reorients the faces on the WP"
if not self.faces:
return
self.faces = [self.projectFace(f) for f in self.faces]
self.oriented = True
def removeHidden(self):
"removes faces pointing outwards"
if not self.faces:
return
faces = []
for f in (self.faces):
if self.isVisible(f):
faces.append(f)
if DEBUG: print len(self.faces)-len(faces) , " faces removed, ", len(faces), " faces retained"
self.faces = faces
self.trimmed = True
def projectFace(self,face):
"projects a single face on the WP"
verts = []
edges = fcgeo.sortEdges(face.Edges)
for e in edges:
v = e.Vertexes[0].Point
v = self.wp.getLocalCoords(v)
verts.append(v)
verts.append(verts[0])
try:
sh = Part.makePolygon(verts)
sh = Part.Face(sh)
except:
if DEBUG: print "Error: Unable to project face on the WP"
return None
else:
return sh
def flattenFace(self,face):
"Returns a face where all vertices have Z = 0"
verts = []
edges = fcgeo.sortEdges(face.Edges)
for e in edges:
v = e.Vertexes[0].Point
verts.append(FreeCAD.Vector(v.x,v.y,0))
verts.append(verts[0])
try:
sh = Part.makePolygon(verts)
sh = Part.Face(sh)
except:
if DEBUG: print "Error: Unable to flatten face"
return None
else:
return sh
def isInside(self,vert,face):
"Returns True if the vert is inside the face in Z projection"
def zOverlaps(self,face1,face2):
"Checks if face1 overlaps face2 in Z direction"
face1 = self.flattenFace(face1)
face2 = self.flattenFace(face2)
# first we check if one of the verts is inside the other face
for v in face1.Vertexes:
if self.isInside(v,face2):
return True
# even so, faces can still overlap if their edges cross each other
for e1 in face1.Edges:
for e2 in face2.Edges:
if fcgeo.findIntersection(e1,e2):
return True
return False
def sortFaces(self,face1,face2):
"zsorts two faces. Returns 1 if face1 is closer, 2 if face2 is closer, 0 otherwise"
# theory from
# http://www.siggraph.org/education/materials/HyperGraph/scanline/visibility/painter.htm
# and practical application http://vrm.ao2.it/ (blender vector renderer)
b1 = face1.BoundBox
b2 = face2.BoundBox
if DEBUG: print "comparing face1: normal ", face1.normalAt(0,0), " with face2: normal ", face2.normalAt(0,0)
# test 1: if faces don't overlap, no comparison possible
if DEBUG: print "doing test 1"
if b1.XMax < b2.XMin:
return 0
if b1.XMin > b2.XMax:
return 0
if b1.YMax < b2.YMin:
return 0
if b1.YMin > b2.YMax:
return 0
if DEBUG: print "passed, faces are overlapping"
# test 2: if Z bounds dont overlap, it's easy to know the closest
if DEBUG: print "doing test 2"
if b1.ZMax < b2.ZMin:
return 2
if b2.ZMax < b1.ZMin:
return 1
if DEBUG: print "passed, faces Z are crossed"
# test 3: all verts of face1 are behind the plane of face2
if DEBUG: print "doing test 3"
norm = face2.normalAt(0,0)
behind = 0
for v in face1.Vertexes:
dv = v.Point.sub(face2.Vertexes[0].Point)
dv = fcvec.project(dv,norm)
if dv.Length:
if dv.getAngle(norm) > 0.1:
behind += 1
if behind == len(face1.Vertexes):
return 2
if DEBUG: print "passed, face 1 is not behind"
# test 4: all verts of face2 are in front of the plane of face1
if DEBUG: print "doing test 4"
norm = face1.normalAt(0,0)
front = 0
for v in face2.Vertexes:
dv = v.Point.sub(face1.Vertexes[0].Point)
dv = fcvec.project(dv,norm)
if dv.Length:
if dv.getAngle(norm) < 0.1:
front += 1
if front == len(face2.Vertexes):
return 2
if DEBUG: print "passed, face 2 is not in front"
# test 5: see if faces projections don't overlap, vertexwise
if DEBUG: print "doing test 5"
if not self.zOverlaps(face1,face2):
return 0
elif not self.zOverlaps(face2,face1):
return 0
if DEBUG: print "passed, faces are overlapping"
if DEBUG: print "Houston, all tests passed, and still no results"
return 0
def sort(self):
"projects a shape on the WP"
if not self.faces:
return
if not self.trimmed:
self.removeHidden()
if not self.oriented:
self.reorient()
faces = self.faces[:]
if DEBUG: print "sorting faces: ", faces
sfaces = []
safecount = 0
while faces:
f1 = faces[0]
for f2 in faces[1:]:
if DEBUG: print "Scanning %d faces" % len(faces)
z = self.sortFaces(f1,f2)
if z == 1:
faces.remove(f2)
sfaces.insert(0,f2)
elif z == 2:
faces.remove(f1)
sfaces.append(f2)
break
safecount += 1
if DEBUG: print "iteration ",safecount
if safecount > (10 * len(faces)):
if DEBUG: print "too long loop, aborting"
break
if DEBUG: print "done Z sorting. ", len(faces), " faces retained, ", len(self.faces)-len(faces), " faces lost."
self.faces = faces
self.sorted = True
def buildDummy(self):
"Builds a dummy object with faces spaced on the Z axis, for visual check"
z = 0
if not self.sorted:
self.sort()
faces = []
for f in self.faces[:]:
ff = self.flattenFace(f)
ff.translate(FreeCAD.Vector(0,0,z))
faces.append(ff)
z += 1
if faces:
c = Part.makeCompound(faces)
Part.show(c)
def getSVG(self):
"Returns a SVG fragment"
if not self.sorted:
self.sort()
svg = ''
for f in self.faces:
svg +='<path '
edges = fcgeo.sortEdges(f.Edges)
v = edges[0].Vertexes[0].Point
svg += 'd="M '+ str(v.x) +' '+ str(v.y) + ' '
for e in edges:
if isinstance(e.Curve,Part.Line) or isinstance(e.Curve,Part.BSplineCurve):
v = e.Vertexes[-1].Point
svg += 'L '+ str(v.x) +' '+ str(v.y) + ' '
elif isinstance(e.Curve,Part.Circle):
r = e.Curve.Radius
v = e.Vertexes[-1].Point
svg += 'A '+ str(r) + ' '+ str(r) +' 0 0 1 '+ str(v.x) +' '
svg += str(v.y) + ' '
svg += '" '
svg += 'stroke="#000000" '
svg += 'stroke-width="0.01 px" '
svg += 'style="stroke-width:0.01;'
svg += 'stroke-miterlimit:1;'
svg += 'stroke-dasharray:none;'
svg += 'fill:#aaaaaa"'
svg += '/>\n'
return svg