#!BPY
"""
Name: 'VRM'
Blender: 241
Group: 'Export'
Tooltip: 'Vector Rendering Method Export Script'
"""
__author__ = "Antonio Ospite"
__url__ = ["blender"]
__version__ = "0.3"
__bpydoc__ = """\
Render the scene and save the result in vector format.
"""
# ---------------------------------------------------------------------
# Copyright (c) 2006 Antonio Ospite
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
#
# ---------------------------------------------------------------------
#
# Additional credits:
# Thanks to Emilio Aguirre for S2flender from which I took inspirations :)
# Thanks to Nikola Radovanovic, the author of the original VRM script,
# the code you read here has been rewritten _almost_ entirely
# from scratch but Nikola gave me the idea, so I thank him publicly.
#
# ---------------------------------------------------------------------
#
# Things TODO for a next release:
# - Switch to the Mesh structure, should be considerably faster
# (partially done, but cannot sort faces, yet)
# - Use a better depth sorting algorithm
# - Review how selections are made (this script uses selection states of
# primitives to represent visibility infos)
# - Implement clipping of primitives and do handle object intersections.
# (for now only clipping for whole objects is supported).
# - Implement Edge Styles (silhouettes, contours, etc.)
# - Implement Edge coloring
# - Use multiple lighting sources in color calculation
# - Implement Shading Styles?
# - Use another representation for the 2D projection?
# Think to a way to merge adjacent polygons that have the same color.
# - Add other Vector Writers.
#
# ---------------------------------------------------------------------
#
# Changelog:
#
# vrm-0.3.py - 2006-05-19
# * First release after code restucturing.
# Now the script offers a useful set of functionalities
# and it can render animations, too.
#
# ---------------------------------------------------------------------
import Blender
from Blender import Scene, Object, Mesh, NMesh, Material, Lamp, Camera
from Blender.Mathutils import *
from math import *
# Some global settings
PRINT_POLYGONS = True
PRINT_EDGES = False
SHOW_HIDDEN_EDGES = False
EDGES_WIDTH = 0.5
POLYGON_EXPANSION_TRICK = True
RENDER_ANIMATION = False
# Does not work in batch mode!!
#OPTIMIZE_FOR_SPACE = True
# ---------------------------------------------------------------------
#
## Projections classes
#
# ---------------------------------------------------------------------
class Projector:
"""Calculate the projection of an object given the camera.
A projector is useful to so some per-object transformation to obtain the
projection of an object given the camera.
The main method is #doProjection# see the method description for the
parameter list.
"""
def __init__(self, cameraObj, canvasRatio):
"""Calculate the projection matrix.
The projection matrix depends, in this case, on the camera settings.
TAKE CARE: This projector expects vertices in World Coordinates!
"""
camera = cameraObj.getData()
aspect = float(canvasRatio[0])/float(canvasRatio[1])
near = camera.clipStart
far = camera.clipEnd
scale = float(camera.scale)
fovy = atan(0.5/aspect/(camera.lens/32))
fovy = fovy * 360.0/pi
# What projection do we want?
if camera.type:
#mP = self._calcOrthoMatrix(fovy, aspect, near, far, 17) #camera.scale)
mP = self._calcOrthoMatrix(fovy, aspect, near, far, scale)
else:
mP = self._calcPerspectiveMatrix(fovy, aspect, near, far)
# View transformation
cam = Matrix(cameraObj.getInverseMatrix())
cam.transpose()
mP = mP * cam
self.projectionMatrix = mP
##
# Public methods
#
def doProjection(self, v):
"""Project the point on the view plane.
Given a vertex calculate the projection using the current projection
matrix.
"""
# Note that we have to work on the vertex using homogeneous coordinates
p = self.projectionMatrix * Vector(v).resize4D()
if p[3]>0:
p[0] = p[0]/p[3]
p[1] = p[1]/p[3]
# restore the size
p[3] = 1.0
p.resize3D()
return p
##
# Private methods
#
def _calcPerspectiveMatrix(self, fovy, aspect, near, far):
"""Return a perspective projection matrix.
"""
top = near * tan(fovy * pi / 360.0)
bottom = -top
left = bottom*aspect
right= top*aspect
x = (2.0 * near) / (right-left)
y = (2.0 * near) / (top-bottom)
a = (right+left) / (right-left)
b = (top+bottom) / (top - bottom)
c = - ((far+near) / (far-near))
d = - ((2*far*near)/(far-near))
m = Matrix(
[x, 0.0, a, 0.0],
[0.0, y, b, 0.0],
[0.0, 0.0, c, d],
[0.0, 0.0, -1.0, 0.0])
return m
def _calcOrthoMatrix(self, fovy, aspect , near, far, scale):
"""Return an orthogonal projection matrix.
"""
# The 11 in the formula was found emiprically
top = near * tan(fovy * pi / 360.0) * (scale * 11)
bottom = -top
left = bottom * aspect
right= top * aspect
rl = right-left
tb = top-bottom
fn = near-far
tx = -((right+left)/rl)
ty = -((top+bottom)/tb)
tz = ((far+near)/fn)
m = Matrix(
[2.0/rl, 0.0, 0.0, tx],
[0.0, 2.0/tb, 0.0, ty],
[0.0, 0.0, 2.0/fn, tz],
[0.0, 0.0, 0.0, 1.0])
return m
# ---------------------------------------------------------------------
#
## 2DObject representation class
#
# ---------------------------------------------------------------------
# TODO: a class to represent the needed properties of a 2D vector image
# For now just using a [N]Mesh structure.
# ---------------------------------------------------------------------
#
## Vector Drawing Classes
#
# ---------------------------------------------------------------------
## A generic Writer
class VectorWriter:
"""
A class for printing output in a vectorial format.
Given a 2D representation of the 3D scene the class is responsible to
write it is a vector format.
Every subclasses of VectorWriter must have at last the following public
methods:
- open(self)
- close(self)
- printCanvas(self, scene,
doPrintPolygons=True, doPrintEdges=False, showHiddenEdges=False):
"""
def __init__(self, fileName):
"""Set the output file name and other properties"""
self.outputFileName = fileName
self.file = None
context = Scene.GetCurrent().getRenderingContext()
self.canvasSize = ( context.imageSizeX(), context.imageSizeY() )
self.startFrame = 1
self.endFrame = 1
self.animation = False
##
# Public Methods
#
def open(self, startFrame=1, endFrame=1):
if startFrame != endFrame:
self.startFrame = startFrame
self.endFrame = endFrame
self.animation = True
self.file = open(self.outputFileName, "w")
print "Outputting to: ", self.outputFileName
return
def close(self):
self.file.close()
return
def printCanvas(self, scene, doPrintPolygons=True, doPrintEdges=False,
showHiddenEdges=False):
"""This is the interface for the needed printing routine.
"""
return
## SVG Writer
class SVGVectorWriter(VectorWriter):
"""A concrete class for writing SVG output.
"""
def __init__(self, fileName):
"""Simply call the parent Contructor.
"""
VectorWriter.__init__(self, fileName)
##
# Public Methods
#
def open(self, startFrame=1, endFrame=1):
"""Do some initialization operations.
"""
VectorWriter.open(self, startFrame, endFrame)
self._printHeader()
def close(self):
"""Do some finalization operation.
"""
self._printFooter()
# remember to call the close method of the parent
VectorWriter.close(self)
def printCanvas(self, scene, doPrintPolygons=True, doPrintEdges=False,
showHiddenEdges=False):
"""Convert the scene representation to SVG.
"""
Objects = scene.getChildren()
context = scene.getRenderingContext()
framenumber = context.currentFrame()
if self.animation:
framestyle = "display:none"
else:
framestyle = "display:block"
# Assign an id to this group so we can set properties on it using DOM
self.file.write("\n" %
(framenumber, framestyle) )
for obj in Objects:
if(obj.getType() != 'Mesh'):
continue
self.file.write("\n" % obj.getName())
mesh = obj.getData(mesh=1)
if doPrintPolygons:
self._printPolygons(mesh)
if doPrintEdges:
self._printEdges(mesh, showHiddenEdges)
self.file.write("\n")
self.file.write("\n")
##
# Private Methods
#
def _calcCanvasCoord(self, v):
"""Convert vertex in scene coordinates to canvas coordinates.
"""
pt = Vector([0, 0, 0])
mW = float(self.canvasSize[0])/2.0
mH = float(self.canvasSize[1])/2.0
# rescale to canvas size
pt[0] = v.co[0]*mW + mW
pt[1] = v.co[1]*mH + mH
pt[2] = v.co[2]
# For now we want (0,0) in the top-left corner of the canvas.
# Mirror and translate along y
pt[1] *= -1
pt[1] += self.canvasSize[1]
return pt
def _printHeader(self):
"""Print SVG header."""
self.file.write("\n")
self.file.write("\n")
self.file.write("\n")
def _printPolygons(self, mesh):
"""Print the selected (visible) polygons.
"""
if len(mesh.faces) == 0:
return
self.file.write("\n")
for face in mesh.faces:
if not face.sel:
continue
self.file.write("\n")
self.file.write("\n")
def _printEdges(self, mesh, showHiddenEdges=False):
"""Print the wireframe using mesh edges.
"""
stroke_width=EDGES_WIDTH
stroke_col = [0, 0, 0]
self.file.write("\n")
for e in mesh.edges:
hidden_stroke_style = ""
# Consider an edge selected if both vertices are selected
if e.v1.sel == 0 or e.v2.sel == 0:
if showHiddenEdges == False:
continue
else:
hidden_stroke_style = ";\n stroke-dasharray:3, 3"
p1 = self._calcCanvasCoord(e.v1)
p2 = self._calcCanvasCoord(e.v2)
self.file.write("\n")
self.file.write("\n")
# ---------------------------------------------------------------------
#
## Rendering Classes
#
# ---------------------------------------------------------------------
class Renderer:
"""Render a scene viewed from a given camera.
This class is responsible of the rendering process, transformation and
projection of the objects in the scene are invoked by the renderer.
The rendering is done using the active camera for the current scene.
"""
def __init__(self):
"""Make the rendering process only for the current scene by default.
We will work on a copy of the scene, be sure that the current scene do
not get modified in any way.
"""
# Render the current Scene, this should be a READ-ONLY property
self._SCENE = Scene.GetCurrent()
# Use the aspect ratio of the scene rendering context
context = self._SCENE.getRenderingContext()
aspect_ratio = float(context.imageSizeX())/float(context.imageSizeY())
self.canvasRatio = (float(context.aspectRatioX())*aspect_ratio,
float(context.aspectRatioY())
)
# Render from the currently active camera
self.cameraObj = self._SCENE.getCurrentCamera()
print dir(self._SCENE)
# Get the list of lighting sources
obj_lst = self._SCENE.getChildren()
self.lights = [ o for o in obj_lst if o.getType() == 'Lamp']
if len(self.lights) == 0:
l = Lamp.New('Lamp')
lobj = Object.New('Lamp')
lobj.link(l)
self.lights.append(lobj)
##
# Public Methods
#
def doRendering(self, outputWriter, animation=False):
"""Render picture or animation and write it out.
The parameters are:
- a Vector writer object that will be used to output the result.
- a flag to tell if we want to render an animation or only the
current frame.
"""
context = self._SCENE.getRenderingContext()
currentFrame = context.currentFrame()
# Handle the animation case
if not animation:
startFrame = currentFrame
endFrame = startFrame
outputWriter.open()
else:
startFrame = context.startFrame()
endFrame = context.endFrame()
outputWriter.open(startFrame, endFrame)
# Do the rendering process frame by frame
print "Start Rendering!"
for f in range(startFrame, endFrame+1):
context.currentFrame(f)
renderedScene = self.doRenderScene(self._SCENE)
outputWriter.printCanvas(renderedScene,
doPrintPolygons = PRINT_POLYGONS,
doPrintEdges = PRINT_EDGES,
showHiddenEdges = SHOW_HIDDEN_EDGES)
# clear the rendered scene
self._SCENE.makeCurrent()
Scene.unlink(renderedScene)
del renderedScene
outputWriter.close()
print "Done!"
context.currentFrame(currentFrame)
def doRenderScene(self, inputScene):
"""Control the rendering process.
Here we control the entire rendering process invoking the operation
needed to transform and project the 3D scene in two dimensions.
"""
# Use some temporary workspace, a full copy of the scene
workScene = inputScene.copy(2)
# Get a projector for this scene.
# NOTE: the projector wants object in world coordinates,
# so we should apply modelview transformations _before_
# projection transformations
proj = Projector(self.cameraObj, self.canvasRatio)
# global processing of the scene
self._doConvertGeometricObjToMesh(workScene)
self._doSceneClipping(workScene)
# FIXME: does not work in batch mode!
#if OPTIMIZE_FOR_SPACE:
# self._joinMeshObjectsInScene(workScene)
self._doSceneDepthSorting(workScene)
# Per object activities
Objects = workScene.getChildren()
for obj in Objects:
if obj.getType() != 'Mesh':
print "Only Mesh supported! - Skipping type:", obj.getType()
continue
print "Rendering: ", obj.getName()
mesh = obj.data
self._doModelToWorldCoordinates(mesh, obj.matrix)
self._doObjectDepthSorting(mesh)
self._doBackFaceCulling(mesh)
self._doColorAndLighting(mesh)
# TODO: 'style' can be a function that determine
# if an edge should be showed?
self._doEdgesStyle(mesh, style=None)
self._doProjection(mesh, proj)
# Update the object data, important! :)
mesh.update()
return workScene
##
# Private Methods
#
# Utility methods
def _getObjPosition(self, obj):
"""Return the obj position in World coordinates.
"""
return obj.matrix.translationPart()
def _cameraViewDirection(self):
"""Get the View Direction form the camera matrix.
"""
return Vector(self.cameraObj.matrix[2]).resize3D()
# Faces methods
def _isFaceVisible(self, face):
"""Determine if a face of an object is visible from the current camera.
The view vector is calculated from the camera location and one of the
vertices of the face (expressed in World coordinates, after applying
modelview transformations).
After those transformations we determine if a face is visible by
computing the angle between the face normal and the view vector, this
angle has to be between -90 and 90 degrees for the face to be visible.
This corresponds somehow to the dot product between the two, if it
results > 0 then the face is visible.
There is no need to normalize those vectors since we are only interested in
the sign of the cross product and not in the product value.
NOTE: here we assume the face vertices are in WorldCoordinates, so
please transform the object _before_ doing the test.
"""
normal = Vector(face.no)
camPos = self._getObjPosition(self.cameraObj)
view_vect = None
# View Vector in orthographics projections is the view Direction of
# the camera
if self.cameraObj.data.getType() == 1:
view_vect = self._cameraViewDirection()
# View vector in perspective projections can be considered as
# the difference between the camera position and one point of
# the face, we choose the farthest point from the camera.
if self.cameraObj.data.getType() == 0:
vv = max( [ ((camPos - Vector(v.co)).length, (camPos - Vector(v.co))) for v in face] )
view_vect = vv[1]
# if d > 0 the face is visible from the camera
d = view_vect * normal
if d > 0:
return True
else:
return False
# Scene methods
def _doConvertGeometricObjToMesh(self, scene):
"""Convert all "geometric" objects to mesh ones.
"""
geometricObjTypes = ['Mesh', 'Surf', 'Curve', 'Text']
Objects = scene.getChildren()
objList = [ o for o in Objects if o.getType() in geometricObjTypes ]
for obj in objList:
old_obj = obj
obj = self._convertToRawMeshObj(obj)
scene.link(obj)
scene.unlink(old_obj)
# Mesh Cleanup
me = obj.getData(mesh=1)
for f in me.faces: f.sel = 1;
for v in me.verts: v.sel = 1;
me.remDoubles(0)
me.triangleToQuad()
me.recalcNormals()
me.update()
def _doSceneClipping(self, scene):
"""Clip objects against the View Frustum.
For now clip away only objects according to their center position.
"""
cpos = self._getObjPosition(self.cameraObj)
view_vect = self._cameraViewDirection()
near = self.cameraObj.data.clipStart
far = self.cameraObj.data.clipEnd
aspect = float(self.canvasRatio[0])/float(self.canvasRatio[1])
fovy = atan(0.5/aspect/(self.cameraObj.data.lens/32))
fovy = fovy * 360.0/pi
Objects = scene.getChildren()
for o in Objects:
if o.getType() != 'Mesh': continue;
obj_vect = Vector(cpos) - self._getObjPosition(o)
d = obj_vect*view_vect
theta = AngleBetweenVecs(obj_vect, view_vect)
# if the object is outside the view frustum, clip it away
if (d < near) or (d > far) or (theta > fovy):
scene.unlink(o)
def _doSceneDepthSorting(self, scene):
"""Sort objects in the scene.
The object sorting is done accordingly to the object centers.
"""
c = self._getObjPosition(self.cameraObj)
by_center_pos = (lambda o1, o2:
(o1.getType() == 'Mesh' and o2.getType() == 'Mesh') and
cmp((self._getObjPosition(o1) - Vector(c)).length,
(self._getObjPosition(o2) - Vector(c)).length)
)
# TODO: implement sorting by bounding box, if obj1.bb is inside obj2.bb,
# then ob1 goes farther than obj2, useful when obj2 has holes
by_bbox = None
Objects = scene.getChildren()
Objects.sort(by_center_pos)
# update the scene
for o in Objects:
scene.unlink(o)
scene.link(o)
def _joinMeshObjectsInScene(self, scene):
"""Merge all the Mesh Objects in a scene into a single Mesh Object.
"""
mesh = Mesh.New()
bigObj = Object.New('Mesh', 'BigOne')
bigObj.link(mesh)
oList = [o for o in scene.getChildren() if o.getType()=='Mesh']
bigObj.join(oList)
scene.link(bigObj)
for o in oList:
scene.unlink(o)
scene.update()
# Per object methods
def _convertToRawMeshObj(self, object):
"""Convert geometry based object to a mesh object.
"""
me = Mesh.New('RawMesh_'+object.name)
me.getFromObject(object.name)
newObject = Object.New('Mesh', 'RawMesh_'+object.name)
newObject.link(me)
# If the object has no materials set a default material
if not me.materials:
me.materials = [Material.New()]
#for f in me.faces: f.mat = 0
newObject.setMatrix(object.getMatrix())
return newObject
def _doModelToWorldCoordinates(self, mesh, matrix):
"""Transform object coordinates to world coordinates.
This step is done simply applying to the object its tranformation
matrix and recalculating its normals.
"""
mesh.transform(matrix, True)
def _doObjectDepthSorting(self, mesh):
"""Sort faces in an object.
The faces in the object are sorted following the distance of the
vertices from the camera position.
"""
c = self._getObjPosition(self.cameraObj)
# hackish sorting of faces
# Sort faces according to the max distance from the camera
by_max_vert_dist = (lambda f1, f2:
cmp(max([(Vector(v.co)-Vector(c)).length for v in f1]),
max([(Vector(v.co)-Vector(c)).length for v in f2])))
# Sort faces according to the min distance from the camera
by_min_vert_dist = (lambda f1, f2:
cmp(min([(Vector(v.co)-Vector(c)).length for v in f1]),
min([(Vector(v.co)-Vector(c)).length for v in f2])))
# Sort faces according to the avg distance from the camera
by_avg_vert_dist = (lambda f1, f2:
cmp(sum([(Vector(v.co)-Vector(c)).length for v in f1])/len(f1),
sum([(Vector(v.co)-Vector(c)).length for v in f2])/len(f2)))
mesh.faces.sort(by_max_vert_dist)
mesh.faces.reverse()
def _doBackFaceCulling(self, mesh):
"""Simple Backface Culling routine.
At this level we simply do a visibility test face by face and then
select the vertices belonging to visible faces.
"""
# Select all vertices, so edges can be displayed even if there are no
# faces
for v in mesh.verts:
v.sel = 1
Mesh.Mode(Mesh.SelectModes['FACE'])
# Loop on faces
for f in mesh.faces:
f.sel = 0
if self._isFaceVisible(f):
f.sel = 1
# Is this the correct way to propagate the face selection info to the
# vertices belonging to a face ??
# TODO: Using the Mesh module this should come for free. Right?
Mesh.Mode(Mesh.SelectModes['VERTEX'])
for f in mesh.faces:
if not f.sel:
for v in f: v.sel = 0;
for f in mesh.faces:
if f.sel:
for v in f: v.sel = 1;
def _doColorAndLighting(self, mesh):
"""Apply an Illumination model to the object.
The Illumination model used is the Phong one, it may be inefficient,
but I'm just learning about rendering and starting from Phong seemed
the most natural way.
"""
# If the mesh has vertex colors already, use them,
# otherwise turn them on and do some calculations
if mesh.hasVertexColours():
return
mesh.hasVertexColours(True)
materials = mesh.materials
# TODO: use multiple lighting sources
light_obj = self.lights[0]
light_pos = self._getObjPosition(light_obj)
light = light_obj.data
camPos = self._getObjPosition(self.cameraObj)
# We do per-face color calculation (FLAT Shading), we can easily turn
# to a per-vertex calculation if we want to implement some shading
# technique. For an example see:
# http://www.miralab.unige.ch/papers/368.pdf
for f in mesh.faces:
if not f.sel:
continue
mat = None
if materials:
mat = materials[f.mat]
# A new default material
if mat == None:
mat = Material.New('defMat')
L = Vector(light_pos).normalize()
V = (Vector(camPos) - Vector(f.v[0].co)).normalize()
N = Vector(f.no).normalize()
R = 2 * (N*L) * N - L
# TODO: Attenuation factor (not used for now)
a0 = 1; a1 = 0.0; a2 = 0.0
d = (Vector(f.v[0].co) - Vector(light_pos)).length
fd = min(1, 1.0/(a0 + a1*d + a2*d*d))
# Ambient component
Ia = 1.0
ka = mat.getAmb() * Vector([0.1, 0.1, 0.1])
Iamb = Ia * ka
# Diffuse component (add light.col for kd)
kd = mat.getRef() * Vector(mat.getRGBCol())
Ip = light.getEnergy()
Idiff = Ip * kd * (N*L)
# Specular component
ks = mat.getSpec() * Vector(mat.getSpecCol())
ns = mat.getHardness()
Ispec = Ip * ks * pow((V * R), ns)
# Emissive component
ki = Vector([mat.getEmit()]*3)
I = ki + Iamb + Idiff + Ispec
# Clamp I values between 0 and 1
I = [ min(c, 1) for c in I]
I = [ max(0, c) for c in I]
tmp_col = [ int(c * 255.0) for c in I]
vcol = NMesh.Col(tmp_col[0], tmp_col[1], tmp_col[2], 255)
f.col = []
for v in f.v:
f.col.append(vcol)
def _doEdgesStyle(self, mesh, style):
"""Process Mesh Edges.
Examples of algorithms:
Contours:
given an edge if its adjacent faces have the same normal (that is
they are complanar), than deselect it.
Silhouettes:
given an edge if one its adjacent faces is frontfacing and the
other is backfacing, than select it, else deselect.
"""
#print "\tTODO: _doEdgeStyle()"
return
def _doProjection(self, mesh, projector):
"""Calculate the Projection for the object.
"""
# TODO: maybe using the object.transform() can be faster?
for v in mesh.verts:
p = projector.doProjection(v.co)
v.co[0] = p[0]
v.co[1] = p[1]
v.co[2] = p[2]
# ---------------------------------------------------------------------
#
## Main Program
#
# ---------------------------------------------------------------------
def vectorize(filename):
"""The vectorizing process is as follows:
- Instanciate the writer and the renderer
- Render!
"""
from Blender import Window
editmode = Window.EditMode()
if editmode: Window.EditMode(0)
writer = SVGVectorWriter(filename)
renderer = Renderer()
renderer.doRendering(writer, RENDER_ANIMATION)
if editmode: Window.EditMode(1)
def vectorize_gui(filename):
"""Draw the gui.
I would like to keep that simple, really.
"""
Blender.Window.FileSelector (vectorize, 'Save SVG', filename)
Blender.Redraw()
# Here the main
if __name__ == "__main__":
basename = Blender.sys.basename(Blender.Get('filename'))
outputfile = Blender.sys.splitext(basename)[0]+".svg"
# with this trick we can run the script in batch mode
try:
vectorize_gui(outputfile)
except:
vectorize(outputfile)