#!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 and do handle object intersections # - 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 # Do not work for now! OPTIMIZE_FOR_SPACE = False # --------------------------------------------------------------------- # ## 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, file): """Simply call the parent Contructor. """ VectorWriter.__init__(self, file) ## # 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() 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\n" % self.canvasSize) if self.animation: self.file.write("""\n\n \n""" % (self.startFrame, self.endFrame, self.startFrame) ) def _printFooter(self): """Print the SVG footer.""" self.file.write("\n\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() # 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 than 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) # Convert geometric object types to mesh Objects geometricObjTypes = ['Mesh', 'Surf', 'Curve'] # TODO: add the Text type Objects = workScene.getChildren() objList = [ o for o in Objects if o.getType() in geometricObjTypes ] for obj in objList: old_obj = obj obj = self._convertToRawMeshObj(obj) workScene.link(obj) workScene.unlink(old_obj) # FIXME: does not work!!, Blender segfaults on joins if OPTIMIZE_FOR_SPACE: self._joinMeshObjectsInScene(workScene) # global processing of the scene self._doClipping() self._doSceneDepthSorting(workScene) # Per object activities Objects = workScene.getChildren() for obj in Objects: if obj.getType() not in geometricObjTypes: print "Only geometric Objects 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 _worldPosition(self, obj): """Return the obj position in World coordinates. """ return obj.matrix.translationPart() def _cameraWorldPosition(self): """Return the camera position in World coordinates. This trick is needed when the camera follows a path and then camera.loc does not correspond to the current real position of the camera in the world. """ return self._worldPosition(self.cameraObj) # 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) c = self._cameraWorldPosition() # View vector in orthographics projections can be considered simply as the # camera position view_vect = Vector(c) #if self.cameraObj.data.getType() == 1: # view_vect = Vector(c) # View vector as in perspective projections # it is the difference between the camera position and one point of # the face, we choose the farthest point. # TODO: make the code more pythonic :) if self.cameraObj.data.getType() == 0: max_len = 0 for vect in face: vv = Vector(c) - Vector(vect.co) if vv.length > max_len: max_len = vv.length view_vect = vv # 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 _doClipping(self): """Clip object against the View Frustum. """ print "TODO: _doClipping()" return def _doSceneDepthSorting(self, scene): """Sort objects in the scene. The object sorting is done accordingly to the object centers. """ c = self._cameraWorldPosition() Objects = scene.getChildren() #Objects.sort(lambda obj1, obj2: # cmp((Vector(obj1.loc) - Vector(c)).length, # (Vector(obj2.loc) - Vector(c)).length # ) # ) Objects.sort(lambda obj1, obj2: cmp((self._worldPosition(obj1) - Vector(c)).length, (self._worldPosition(obj2) - Vector(c)).length ) ) # 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. """ bigObj = Object.New('Mesh', 'BigOne') oList = [o for o in scene.getChildren() if o.getType()=='Mesh'] print "Before join", oList bigObj.join(oList) print "After join" scene.link(bigObj) for o in oList: scene.unlink(o) # 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) 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._cameraWorldPosition() # hackish sorting of faces mesh.faces.sort( lambda f1, f2: # Sort faces according to the min distance from the camera #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 max distance from the camera 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 avg distance from the camera #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.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 without faces can be displayed 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 class 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._worldPosition(light_obj) light = light_obj.data camPos = self._cameraWorldPosition() # 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 not mat: 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. (For now copy the edge data, in next version it can be a place where recognize silouhettes and/or contours). input: an edge list return: a processed edge list """ #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__": import os outputfile = os.path.splitext(Blender.Get('filename'))[0]+".svg" # with this trick we can run the script in batch mode try: vectorize_gui(outputfile) except: vectorize(outputfile)