# Contributed by Seva Alekseyev with National Institutes of Health, 2016 # Cura is released under the terms of the LGPLv3 or higher. from math import pi, sin, cos, sqrt from typing import Dict import numpy from UM.Job import Job from UM.Logger import Logger from UM.Math.Matrix import Matrix from UM.Math.Vector import Vector from UM.Mesh.MeshBuilder import MeshBuilder from UM.Mesh.MeshReader import MeshReader from cura.Scene.CuraSceneNode import CuraSceneNode as SceneNode MYPY = False try: if not MYPY: import xml.etree.cElementTree as ET except ImportError: import xml.etree.ElementTree as ET # TODO: preserve the structure of scenes that contain several objects # Use CADPart, for example, to distinguish between separate objects DEFAULT_SUBDIV = 16 # Default subdivision factor for spheres, cones, and cylinders EPSILON = 0.000001 class Shape: # Expects verts in MeshBuilder-ready format, as a n by 3 mdarray # with vertices stored in rows def __init__(self, verts, faces, index_base, name): self.verts = verts self.faces = faces # Those are here for debugging purposes only self.index_base = index_base self.name = name class X3DReader(MeshReader): def __init__(self) -> None: super().__init__() self._supported_extensions = [".x3d"] self._namespaces = {} # type: Dict[str, str] # Main entry point # Reads the file, returns a SceneNode (possibly with nested ones), or None def _read(self, file_name): try: self.defs = {} self.shapes = [] tree = ET.parse(file_name) xml_root = tree.getroot() if xml_root.tag != "X3D": return None scale = 1000 # Default X3D unit it one meter, while Cura's is one millimeters if xml_root[0].tag == "head": for head_node in xml_root[0]: if head_node.tag == "unit" and head_node.attrib.get("category") == "length": scale *= float(head_node.attrib["conversionFactor"]) break xml_scene = xml_root[1] else: xml_scene = xml_root[0] if xml_scene.tag != "Scene": return None self.transform = Matrix() self.transform.setByScaleFactor(scale) self.index_base = 0 # Traverse the scene tree, populate the shapes list self.processChildNodes(xml_scene) if self.shapes: builder = MeshBuilder() builder.setVertices(numpy.concatenate([shape.verts for shape in self.shapes])) builder.setIndices(numpy.concatenate([shape.faces for shape in self.shapes])) builder.calculateNormals() builder.setFileName(file_name) mesh_data = builder.build() # Manually try and get the extents of the mesh_data. This should prevent nasty NaN issues from # leaving the reader. mesh_data.getExtents() node = SceneNode() node.setMeshData(mesh_data) node.setSelectable(True) node.setName(file_name) else: return None except Exception: Logger.logException("e", "Exception in X3D reader") return None return node # ------------------------- XML tree traversal def processNode(self, xml_node): xml_node = self.resolveDefUse(xml_node) if xml_node is None: return tag = xml_node.tag if tag in ("Group", "StaticGroup", "CADAssembly", "CADFace", "CADLayer", "Collision"): self.processChildNodes(xml_node) if tag == "CADPart": self.processTransform(xml_node) # TODO: split the parts elif tag == "LOD": self.processNode(xml_node[0]) elif tag == "Transform": self.processTransform(xml_node) elif tag == "Shape": self.processShape(xml_node) def processShape(self, xml_node): # Find the geometry and the appearance inside the Shape geometry = appearance = None for sub_node in xml_node: if sub_node.tag == "Appearance" and not appearance: appearance = self.resolveDefUse(sub_node) elif sub_node.tag in self.geometry_importers and not geometry: geometry = self.resolveDefUse(sub_node) # TODO: appearance is completely ignored. At least apply the material color... if not geometry is None: try: self.verts = self.faces = [] # Safeguard self.geometry_importers[geometry.tag](self, geometry) m = self.transform.getData() verts = m.dot(self.verts)[:3].transpose() self.shapes.append(Shape(verts, self.faces, self.index_base, geometry.tag)) self.index_base += len(verts) except Exception: Logger.logException("e", "Exception in X3D reader while reading %s", geometry.tag) # Returns the referenced node if the node has USE, the same node otherwise. # May return None is USE points at a nonexistent node # In X3DOM, when both DEF and USE are in the same node, DEF is ignored. # Big caveat: XML element objects may evaluate to boolean False!!! # Don't ever use "if node:", use "if not node is None:" instead def resolveDefUse(self, node): USE = node.attrib.get("USE") if USE: return self.defs.get(USE, None) DEF = node.attrib.get("DEF") if DEF: self.defs[DEF] = node return node def processChildNodes(self, node): for c in node: self.processNode(c) Job.yieldThread() # Since this is a grouping node, will recurse down the tree. # According to the spec, the final transform matrix is: # T * C * R * SR * S * -SR * -C # Where SR corresponds to the rotation matrix to scaleOrientation # C and SR are rather exotic. S, slightly less so. def processTransform(self, node): rot = readRotation(node, "rotation", (0, 0, 1, 0)) # (angle, axisVactor) tuple trans = readVector(node, "translation", (0, 0, 0)) # Vector scale = readVector(node, "scale", (1, 1, 1)) # Vector center = readVector(node, "center", (0, 0, 0)) # Vector scale_orient = readRotation(node, "scaleOrientation", (0, 0, 1, 0)) # (angle, axisVactor) tuple # Store the previous transform; in Cura, the default matrix multiplication is in place prev = Matrix(self.transform.getData()) # It's deep copy, I've checked # The rest of transform manipulation will be applied in place got_center = (center.x != 0 or center.y != 0 or center.z != 0) T = self.transform if trans.x != 0 or trans.y != 0 or trans.z != 0: T.translate(trans) if got_center: T.translate(center) if rot[0] != 0: T.rotateByAxis(*rot) if scale.x != 1 or scale.y != 1 or scale.z != 1: got_scale_orient = scale_orient[0] != 0 if got_scale_orient: T.rotateByAxis(*scale_orient) # No scale by vector in place operation in UM S = Matrix() S.setByScaleVector(scale) T.multiply(S) if got_scale_orient: T.rotateByAxis(-scale_orient[0], scale_orient[1]) if got_center: T.translate(-center) self.processChildNodes(node) self.transform = prev # ------------------------- Geometry importers # They are supposed to fill the self.verts and self.faces arrays, the caller will do the rest # Primitives def processGeometryBox(self, node): (dx, dy, dz) = readFloatArray(node, "size", [2, 2, 2]) dx /= 2 dy /= 2 dz /= 2 self.reserveFaceAndVertexCount(12, 8) # xz plane at +y, ccw self.addVertex(dx, dy, dz) self.addVertex(-dx, dy, dz) self.addVertex(-dx, dy, -dz) self.addVertex(dx, dy, -dz) # xz plane at -y self.addVertex(dx, -dy, dz) self.addVertex(-dx, -dy, dz) self.addVertex(-dx, -dy, -dz) self.addVertex(dx, -dy, -dz) self.addQuad(0, 1, 2, 3) # +y self.addQuad(4, 0, 3, 7) # +x self.addQuad(7, 3, 2, 6) # -z self.addQuad(6, 2, 1, 5) # -x self.addQuad(5, 1, 0, 4) # +z self.addQuad(7, 6, 5, 4) # -y # The sphere is subdivided into nr rings and ns segments def processGeometrySphere(self, node): r = readFloat(node, "radius", 0.5) subdiv = readIntArray(node, "subdivision", None) if subdiv: if len(subdiv) == 1: nr = ns = subdiv[0] else: (nr, ns) = subdiv else: nr = ns = DEFAULT_SUBDIV lau = pi / nr # Unit angle of latitude (rings) for the given tesselation lou = 2 * pi / ns # Unit angle of longitude (segments) self.reserveFaceAndVertexCount(ns*(nr*2 - 2), 2 + (nr - 1)*ns) # +y and -y poles self.addVertex(0, r, 0) self.addVertex(0, -r, 0) # The non-polar vertices go from x=0, negative z plane counterclockwise - # to -x, to +z, to +x, back to -z for ring in range(1, nr): for seg in range(ns): self.addVertex(-r*sin(lou * seg) * sin(lau * ring), r*cos(lau * ring), -r*cos(lou * seg) * sin(lau * ring)) vb = 2 + (nr - 2) * ns # First vertex index for the bottom cap # Faces go in order: top cap, sides, bottom cap. # Sides go by ring then by segment. # Caps # Top cap face vertices go in order: down right up # (starting from +y pole) # Bottom cap goes: up left down (starting from -y pole) for seg in range(ns): self.addTri(0, seg + 2, (seg + 1) % ns + 2) self.addTri(1, vb + (seg + 1) % ns, vb + seg) # Sides # Side face vertices go in order: down right upleft, downright up left for ring in range(nr - 2): tvb = 2 + ring * ns # First vertex index for the top edge of the ring bvb = tvb + ns # First vertex index for the bottom edge of the ring for seg in range(ns): nseg = (seg + 1) % ns self.addQuad(tvb + seg, bvb + seg, bvb + nseg, tvb + nseg) def processGeometryCone(self, node): r = readFloat(node, "bottomRadius", 1) height = readFloat(node, "height", 2) bottom = readBoolean(node, "bottom", True) side = readBoolean(node, "side", True) n = readInt(node, "subdivision", DEFAULT_SUBDIV) d = height / 2 angle = 2 * pi / n self.reserveFaceAndVertexCount((n if side else 0) + (n-2 if bottom else 0), n+1) # Vertex 0 is the apex, vertices 1..n are the bottom self.addVertex(0, d, 0) for i in range(n): self.addVertex(-r * sin(angle * i), -d, -r * cos(angle * i)) # Side face vertices go: up down right if side: for i in range(n): self.addTri(1 + (i + 1) % n, 0, 1 + i) if bottom: for i in range(2, n): self.addTri(1, i, i+1) def processGeometryCylinder(self, node): r = readFloat(node, "radius", 1) height = readFloat(node, "height", 2) bottom = readBoolean(node, "bottom", True) side = readBoolean(node, "side", True) top = readBoolean(node, "top", True) n = readInt(node, "subdivision", DEFAULT_SUBDIV) nn = n * 2 angle = 2 * pi / n hh = height/2 self.reserveFaceAndVertexCount((nn if side else 0) + (n - 2 if top else 0) + (n - 2 if bottom else 0), nn) # The seam is at x=0, z=-r, vertices go ccw - # to pos x, to neg z, to neg x, back to neg z for i in range(n): rs = -r * sin(angle * i) rc = -r * cos(angle * i) self.addVertex(rs, hh, rc) self.addVertex(rs, -hh, rc) if side: for i in range(n): ni = (i + 1) % n self.addQuad(ni * 2 + 1, ni * 2, i * 2, i * 2 + 1) for i in range(2, nn-3, 2): if top: self.addTri(0, i, i+2) if bottom: self.addTri(1, i+1, i+3) # Semi-primitives def processGeometryElevationGrid(self, node): dx = readFloat(node, "xSpacing", 1) dz = readFloat(node, "zSpacing", 1) nx = readInt(node, "xDimension", 0) nz = readInt(node, "zDimension", 0) height = readFloatArray(node, "height", False) ccw = readBoolean(node, "ccw", True) if nx <= 0 or nz <= 0 or len(height) < nx*nz: return # That's weird, the wording of the standard suggests grids with zero quads are somehow valid self.reserveFaceAndVertexCount(2*(nx-1)*(nz-1), nx*nz) for z in range(nz): for x in range(nx): self.addVertex(x * dx, height[z*nx + x], z * dz) for z in range(1, nz): for x in range(1, nx): self.addTriFlip((z - 1)*nx + x - 1, z*nx + x, (z - 1)*nx + x, ccw) self.addTriFlip((z - 1)*nx + x - 1, z*nx + x - 1, z*nx + x, ccw) def processGeometryExtrusion(self, node): ccw = readBoolean(node, "ccw", True) begin_cap = readBoolean(node, "beginCap", True) end_cap = readBoolean(node, "endCap", True) cross = readFloatArray(node, "crossSection", (1, 1, 1, -1, -1, -1, -1, 1, 1, 1)) cross = [(cross[i], cross[i+1]) for i in range(0, len(cross), 2)] spine = readFloatArray(node, "spine", (0, 0, 0, 0, 1, 0)) spine = [(spine[i], spine[i+1], spine[i+2]) for i in range(0, len(spine), 3)] orient = readFloatArray(node, "orientation", None) if orient: # This converts X3D's axis/angle rotation to a 3x3 numpy matrix def toRotationMatrix(rot): (x, y, z) = rot[:3] a = rot[3] s = sin(a) c = cos(a) t = 1-c return numpy.array(( (x * x * t + c, x * y * t - z*s, x * z * t + y * s), (x * y * t + z*s, y * y * t + c, y * z * t - x * s), (x * z * t - y * s, y * z * t + x * s, z * z * t + c))) orient = [toRotationMatrix(orient[i:i+4]) if orient[i+3] != 0 else None for i in range(0, len(orient), 4)] scale = readFloatArray(node, "scale", None) if scale: scale = [numpy.array(((scale[i], 0, 0), (0, 1, 0), (0, 0, scale[i+1]))) if scale[i] != 1 or scale[i+1] != 1 else None for i in range(0, len(scale), 2)] # Special treatment for the closed spine and cross section. # Let's save some memory by not creating identical but distinct vertices; # later we'll introduce conditional logic to link the last vertex with # the first one where necessary. crossClosed = cross[0] == cross[-1] if crossClosed: cross = cross[:-1] nc = len(cross) cross = [numpy.array((c[0], 0, c[1])) for c in cross] ncf = nc if crossClosed else nc - 1 # Face count along the cross; for closed cross, it's the same as the # respective vertex count spine_closed = spine[0] == spine[-1] if spine_closed: spine = spine[:-1] ns = len(spine) spine = [Vector(*s) for s in spine] nsf = ns if spine_closed else ns - 1 # This will be used for fallback, where the current spine point joins # two collinear spine segments. No need to recheck the case of the # closed spine/last-to-first point juncture; if there's an angle there, # it would kick in on the first iteration of the main loop by spine. def findFirstAngleNormal(): for i in range(1, ns - 1): spt = spine[i] z = (spine[i + 1] - spt).cross(spine[i - 1] - spt) if z.length() > EPSILON: return z # All the spines are collinear. Fallback to the rotated source # XZ plane. # TODO: handle the situation where the first two spine points match if len(spine) < 2: return Vector(0, 0, 1) v = spine[1] - spine[0] orig_y = Vector(0, 1, 0) orig_z = Vector(0, 0, 1) if v.cross(orig_y).length() > EPSILON: # Spine at angle with global y - rotate the z accordingly a = v.cross(orig_y) # Axis of rotation to get to the Z (x, y, z) = a.normalized().getData() s = a.length()/v.length() c = sqrt(1-s*s) t = 1-c m = numpy.array(( (x * x * t + c, x * y * t + z*s, x * z * t - y * s), (x * y * t - z*s, y * y * t + c, y * z * t + x * s), (x * z * t + y * s, y * z * t - x * s, z * z * t + c))) orig_z = Vector(*m.dot(orig_z.getData())) return orig_z self.reserveFaceAndVertexCount(2*nsf*ncf + (nc - 2 if begin_cap else 0) + (nc - 2 if end_cap else 0), ns*nc) z = None for i, spt in enumerate(spine): if (i > 0 and i < ns - 1) or spine_closed: snext = spine[(i + 1) % ns] sprev = spine[(i - 1 + ns) % ns] y = snext - sprev vnext = snext - spt vprev = sprev - spt try_z = vnext.cross(vprev) # Might be zero, then all kinds of fallback if try_z.length() > EPSILON: if z is not None and try_z.dot(z) < 0: try_z = -try_z z = try_z elif not z: # No z, and no previous z. # Look ahead, see if there's at least one point where # spines are not collinear. z = findFirstAngleNormal() elif i == 0: # And non-crossed snext = spine[i + 1] y = snext - spt z = findFirstAngleNormal() else: # last point and not crossed sprev = spine[i - 1] y = spt - sprev # If there's more than one point in the spine, z is already set. # One point in the spline is an error anyway. z = z.normalized() y = y.normalized() x = y.cross(z) # Already normalized m = numpy.array(((x.x, y.x, z.x), (x.y, y.y, z.y), (x.z, y.z, z.z))) # Columns are the unit vectors for the xz plane for the cross-section if orient: mrot = orient[i] if len(orient) > 1 else orient[0] if not mrot is None: m = m.dot(mrot) # Tested against X3DOM, the result matches, still not sure :( if scale: mscale = scale[i] if len(scale) > 1 else scale[0] if not mscale is None: m = m.dot(mscale) # First the cross-section 2-vector is scaled, # then rotated (which may make it a 3-vector), # then applied to the xz plane unit vectors sptv3 = numpy.array(spt.getData()[:3]) for cpt in cross: v = sptv3 + m.dot(cpt) self.addVertex(*v) if begin_cap: self.addFace([x for x in range(nc - 1, -1, -1)], ccw) # Order of edges in the face: forward along cross, forward along spine, # backward along cross, backward along spine, flipped if now ccw. # This order is assumed later in the texture coordinate assignment; # please don't change without syncing. for s in range(ns - 1): for c in range(ncf): self.addQuadFlip(s * nc + c, s * nc + (c + 1) % nc, (s + 1) * nc + (c + 1) % nc, (s + 1) * nc + c, ccw) if spine_closed: # The faces between the last and the first spine points b = (ns - 1) * nc for c in range(ncf): self.addQuadFlip(b + c, b + (c + 1) % nc, (c + 1) % nc, c, ccw) if end_cap: self.addFace([(ns - 1) * nc + x for x in range(0, nc)], ccw) # Triangle meshes # Helper for numerous nodes with a Coordinate subnode holding vertices # That all triangle meshes and IndexedFaceSet # num_faces can be a function, in case the face count is a function of vertex count def startCoordMesh(self, node, num_faces): ccw = readBoolean(node, "ccw", True) self.readVertices(node) # This will allocate and fill the vertex array if hasattr(num_faces, "__call__"): num_faces = num_faces(self.getVertexCount()) self.reserveFaceCount(num_faces) return ccw def processGeometryIndexedTriangleSet(self, node): index = readIntArray(node, "index", []) num_faces = len(index) // 3 ccw = int(self.startCoordMesh(node, num_faces)) for i in range(0, num_faces*3, 3): self.addTri(index[i + 1 - ccw], index[i + ccw], index[i+2]) def processGeometryIndexedTriangleStripSet(self, node): strips = readIndex(node, "index") ccw = int(self.startCoordMesh(node, sum([len(strip) - 2 for strip in strips]))) for strip in strips: sccw = ccw # Running CCW value, reset for each strip for i in range(len(strip) - 2): self.addTri(strip[i + 1 - sccw], strip[i + sccw], strip[i+2]) sccw = 1 - sccw def processGeometryIndexedTriangleFanSet(self, node): fans = readIndex(node, "index") ccw = int(self.startCoordMesh(node, sum([len(fan) - 2 for fan in fans]))) for fan in fans: for i in range(1, len(fan) - 1): self.addTri(fan[0], fan[i + 1 - ccw], fan[i + ccw]) def processGeometryTriangleSet(self, node): ccw = int(self.startCoordMesh(node, lambda num_vert: num_vert // 3)) for i in range(0, self.getVertexCount(), 3): self.addTri(i + 1 - ccw, i + ccw, i+2) def processGeometryTriangleStripSet(self, node): strips = readIntArray(node, "stripCount", []) ccw = int(self.startCoordMesh(node, sum([n-2 for n in strips]))) vb = 0 for n in strips: sccw = ccw for i in range(n-2): self.addTri(vb + i + 1 - sccw, vb + i + sccw, vb + i + 2) sccw = 1 - sccw vb += n def processGeometryTriangleFanSet(self, node): fans = readIntArray(node, "fanCount", []) ccw = int(self.startCoordMesh(node, sum([n-2 for n in fans]))) vb = 0 for n in fans: for i in range(1, n-1): self.addTri(vb, vb + i + 1 - ccw, vb + i + ccw) vb += n # Quad geometries from the CAD module, might be relevant for printing def processGeometryQuadSet(self, node): ccw = self.startCoordMesh(node, lambda num_vert: 2*(num_vert // 4)) for i in range(0, self.getVertexCount(), 4): self.addQuadFlip(i, i+1, i+2, i+3, ccw) def processGeometryIndexedQuadSet(self, node): index = readIntArray(node, "index", []) num_quads = len(index) // 4 ccw = self.startCoordMesh(node, num_quads*2) for i in range(0, num_quads*4, 4): self.addQuadFlip(index[i], index[i+1], index[i+2], index[i+3], ccw) # 2D polygon geometries # Won't work for now, since Cura expects every mesh to have a nontrivial convex hull # The only way around that is merging meshes. def processGeometryDisk2D(self, node): innerRadius = readFloat(node, "innerRadius", 0) outerRadius = readFloat(node, "outerRadius", 1) n = readInt(node, "subdivision", DEFAULT_SUBDIV) angle = 2 * pi / n self.reserveFaceAndVertexCount(n*4 if innerRadius else n-2, n*2 if innerRadius else n) for i in range(n): s = sin(angle * i) c = cos(angle * i) self.addVertex(outerRadius*c, outerRadius*s, 0) if innerRadius: self.addVertex(innerRadius*c, innerRadius*s, 0) ni = (i+1) % n self.addQuad(2*i, 2*ni, 2*ni+1, 2*i+1) if not innerRadius: for i in range(2, n): self.addTri(0, i-1, i) def processGeometryRectangle2D(self, node): (x, y) = readFloatArray(node, "size", (2, 2)) self.reserveFaceAndVertexCount(2, 4) self.addVertex(-x/2, -y/2, 0) self.addVertex(x/2, -y/2, 0) self.addVertex(x/2, y/2, 0) self.addVertex(-x/2, y/2, 0) self.addQuad(0, 1, 2, 3) def processGeometryTriangleSet2D(self, node): verts = readFloatArray(node, "vertices", ()) num_faces = len(verts) // 6 verts = [(verts[i], verts[i+1], 0) for i in range(0, 6 * num_faces, 2)] self.reserveFaceAndVertexCount(num_faces, num_faces * 3) for vert in verts: self.addVertex(*vert) # The front face is on the +Z side, so CCW is a variable for i in range(0, num_faces*3, 3): a = Vector(*verts[i+2]) - Vector(*verts[i]) b = Vector(*verts[i+1]) - Vector(*verts[i]) self.addTriFlip(i, i+1, i+2, a.x*b.y > a.y*b.x) # General purpose polygon mesh def processGeometryIndexedFaceSet(self, node): faces = readIndex(node, "coordIndex") ccw = self.startCoordMesh(node, sum([len(face) - 2 for face in faces])) for face in faces: if len(face) == 3: self.addTriFlip(face[0], face[1], face[2], ccw) elif len(face) > 3: self.addFace(face, ccw) geometry_importers = { "IndexedFaceSet": processGeometryIndexedFaceSet, "IndexedTriangleSet": processGeometryIndexedTriangleSet, "IndexedTriangleStripSet": processGeometryIndexedTriangleStripSet, "IndexedTriangleFanSet": processGeometryIndexedTriangleFanSet, "TriangleSet": processGeometryTriangleSet, "TriangleStripSet": processGeometryTriangleStripSet, "TriangleFanSet": processGeometryTriangleFanSet, "QuadSet": processGeometryQuadSet, "IndexedQuadSet": processGeometryIndexedQuadSet, "TriangleSet2D": processGeometryTriangleSet2D, "Rectangle2D": processGeometryRectangle2D, "Disk2D": processGeometryDisk2D, "ElevationGrid": processGeometryElevationGrid, "Extrusion": processGeometryExtrusion, "Sphere": processGeometrySphere, "Box": processGeometryBox, "Cylinder": processGeometryCylinder, "Cone": processGeometryCone } # Parses the Coordinate.@point field, fills the verts array. def readVertices(self, node): for c in node: if c.tag == "Coordinate": c = self.resolveDefUse(c) if not c is None: pt = c.attrib.get("point") if pt: # allow the list of float values in 'point' attribute to # be separated by commas or whitespace as per spec of # XML encoding of X3D # Ref ISO/IEC 19776-1:2015 : Section 5.1.2 co = [float(x) for vec in pt.split(',') for x in vec.split()] num_verts = len(co) // 3 self.verts = numpy.empty((4, num_verts), dtype=numpy.float32) self.verts[3,:] = numpy.ones((num_verts), dtype=numpy.float32) # Group by three for i in range(num_verts): self.verts[:3,i] = co[3*i:3*i+3] # Mesh builder helpers def reserveFaceAndVertexCount(self, num_faces, num_verts): # Unlike the Cura MeshBuilder, we use 4-vectors stored as columns for easier transform self.verts = numpy.zeros((4, num_verts), dtype=numpy.float32) self.verts[3,:] = numpy.ones((num_verts), dtype=numpy.float32) self.num_verts = 0 self.reserveFaceCount(num_faces) def reserveFaceCount(self, num_faces): self.faces = numpy.zeros((num_faces, 3), dtype=numpy.int32) self.num_faces = 0 def getVertexCount(self): return self.verts.shape[1] def addVertex(self, x, y, z): self.verts[0, self.num_verts] = x self.verts[1, self.num_verts] = y self.verts[2, self.num_verts] = z self.num_verts += 1 # Indices are 0-based for this shape, but they won't be zero-based in the merged mesh def addTri(self, a, b, c): self.faces[self.num_faces, 0] = self.index_base + a self.faces[self.num_faces, 1] = self.index_base + b self.faces[self.num_faces, 2] = self.index_base + c self.num_faces += 1 def addTriFlip(self, a, b, c, ccw): if ccw: self.addTri(a, b, c) else: self.addTri(b, a, c) # Needs to be convex, but not necessaily planar # Assumed ccw, cut along the ac diagonal def addQuad(self, a, b, c, d): self.addTri(a, b, c) self.addTri(c, d, a) def addQuadFlip(self, a, b, c, d, ccw): if ccw: self.addTri(a, b, c) self.addTri(c, d, a) else: self.addTri(a, c, b) self.addTri(c, a, d) # Arbitrary polygon triangulation. # Doesn't assume convexity and doesn't check the "convex" flag in the file. # Works by the "cutting of ears" algorithm: # - Find an outer vertex with the smallest angle and no vertices inside its adjacent triangle # - Remove the triangle at that vertex # - Repeat until done # Vertex coordinates are supposed to be already set def addFace(self, indices, ccw): # Resolve indices to coordinates for faster math face = [Vector(data=self.verts[0:3, i]) for i in indices] # Need a normal to the plane so that we can know which vertices form inner angles normal = findOuterNormal(face) if not normal: # Couldn't find an outer edge, non-planar polygon maybe? return # Find the vertex with the smallest inner angle and no points inside, cut off. Repeat until done n = len(face) vi = [i for i in range(n)] # We'll be using this to kick vertices from the face while n > 3: max_cos = EPSILON # We don't want to check anything on Pi angles i_min = 0 # max cos corresponds to min angle for i in range(n): inext = (i + 1) % n iprev = (i + n - 1) % n v = face[vi[i]] next = face[vi[inext]] - v prev = face[vi[iprev]] - v nextXprev = next.cross(prev) if nextXprev.dot(normal) > EPSILON: # If it's an inner angle cos = next.dot(prev) / (next.length() * prev.length()) if cos > max_cos: # Check if there are vertices inside the triangle no_points_inside = True for j in range(n): if j != i and j != iprev and j != inext: vx = face[vi[j]] - v if pointInsideTriangle(vx, next, prev, nextXprev): no_points_inside = False break if no_points_inside: max_cos = cos i_min = i self.addTriFlip(indices[vi[(i_min + n - 1) % n]], indices[vi[i_min]], indices[vi[(i_min + 1) % n]], ccw) vi.pop(i_min) n -= 1 self.addTriFlip(indices[vi[0]], indices[vi[1]], indices[vi[2]], ccw) # ------------------------------------------------------------ # X3D field parsers # ------------------------------------------------------------ def readFloatArray(node, attr, default): s = node.attrib.get(attr) if not s: return default return [float(x) for x in s.split()] def readIntArray(node, attr, default): s = node.attrib.get(attr) if not s: return default return [int(x, 0) for x in s.split()] def readFloat(node, attr, default): s = node.attrib.get(attr) if not s: return default return float(s) def readInt(node, attr, default): s = node.attrib.get(attr) if not s: return default return int(s, 0) def readBoolean(node, attr, default): s = node.attrib.get(attr) if not s: return default return s.lower() == "true" def readVector(node, attr, default): v = readFloatArray(node, attr, default) return Vector(v[0], v[1], v[2]) def readRotation(node, attr, default): v = readFloatArray(node, attr, default) return (v[3], Vector(v[0], v[1], v[2])) # Returns the -1-separated runs def readIndex(node, attr): v = readIntArray(node, attr, []) chunks = [] chunk = [] for i in range(len(v)): if v[i] == -1: if chunk: chunks.append(chunk) chunk = [] else: chunk.append(v[i]) if chunk: chunks.append(chunk) return chunks # Given a face as a sequence of vectors, returns a normal to the polygon place that forms a right triple # with a vector along the polygon sequence and a vector backwards def findOuterNormal(face): n = len(face) for i in range(n): for j in range(i+1, n): edge = face[j] - face[i] if edge.length() > EPSILON: edge = edge.normalized() prev_rejection = Vector() is_outer = True for k in range(n): if k != i and k != j: pt = face[k] - face[i] pte = pt.dot(edge) rejection = pt - edge*pte if rejection.dot(prev_rejection) < -EPSILON: # points on both sides of the edge - not an outer one is_outer = False break elif rejection.length() > prev_rejection.length(): # Pick a greater rejection for numeric stability prev_rejection = rejection if is_outer: # Found an outer edge, prev_rejection is the rejection inside the face. Generate a normal. return edge.cross(prev_rejection) return False # Given two *collinear* vectors a and b, returns the coefficient that takes b to a. # No error handling. # For stability, taking the ration between the biggest coordinates would be better... def ratio(a, b): if b.x > EPSILON or b.x < -EPSILON: return a.x / b.x elif b.y > EPSILON or b.y < -EPSILON: return a.y / b.y else: return a.z / b.z def pointInsideTriangle(vx, next, prev, nextXprev): vxXprev = vx.cross(prev) r = ratio(vxXprev, nextXprev) if r < 0: return False vxXnext = vx.cross(next) s = -ratio(vxXnext, nextXprev) return s > 0 and (s + r) < 1