mirror of
https://github.com/yeicor-3d/yet-another-cad-viewer.git
synced 2025-12-20 22:47:04 +01:00
114 lines
3.5 KiB
Python
114 lines
3.5 KiB
Python
import hashlib
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import io
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import re
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from OCP.BRep import BRep_Tool
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from OCP.BRepAdaptor import BRepAdaptor_Curve
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from OCP.GCPnts import GCPnts_TangentialDeflection
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from OCP.TopExp import TopExp
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from OCP.TopLoc import TopLoc_Location
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from OCP.TopTools import TopTools_IndexedMapOfShape
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from OCP.TopoDS import TopoDS_Face, TopoDS_Edge, TopoDS_Shape, TopoDS_Vertex
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from build123d import Shape, Vertex
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from pygltflib import GLTF2
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import mylogger
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from gltf import GLTFMgr
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# TODO: Migrate to ocp-tessellate to reuse the tessellation logic
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def tessellate(
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ocp_shape: TopoDS_Shape,
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tolerance: float = 0.1,
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angular_tolerance: float = 0.1,
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faces: bool = True,
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edges: bool = True,
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vertices: bool = False,
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) -> GLTF2:
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"""Tessellate a whole shape into a list of triangle vertices and a list of triangle indices."""
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mgr = GLTFMgr()
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shape = Shape(ocp_shape)
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# Perform tessellation tasks
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if faces:
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for face in shape.faces():
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_tessellate_face(mgr, face.wrapped, tolerance, angular_tolerance)
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if edges:
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for edge in shape.edges():
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_tessellate_edge(mgr, edge.wrapped, angular_tolerance, angular_tolerance)
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if vertices:
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for vertex in shape.vertices():
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_tessellate_vertex(mgr, vertex.wrapped)
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return mgr.gltf
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def _tessellate_face(
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mgr: GLTFMgr,
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ocp_face: TopoDS_Face,
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tolerance: float = 1e-3,
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angular_tolerance: float = 0.1
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):
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face = Shape(ocp_face)
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face.mesh(tolerance, angular_tolerance)
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poly = BRep_Tool.Triangulation_s(face.wrapped, TopLoc_Location())
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if poly is None:
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mylogger.logger.warn("No triangulation found for face")
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return GLTF2()
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tri_mesh = face.tessellate(tolerance, angular_tolerance)
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# Get UV of each face from the parameters
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uv = [
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(v.X(), v.Y())
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for v in (poly.UVNode(i) for i in range(1, poly.NbNodes() + 1))
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]
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vertices = [(v.X, v.Y, v.Z) for v in tri_mesh[0]]
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indices = tri_mesh[1]
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mgr.add_face(vertices, indices, uv)
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def _tessellate_edge(
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mgr: GLTFMgr,
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ocp_edge: TopoDS_Edge,
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angular_deflection: float = 0.1,
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curvature_deflection: float = 0.1,
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):
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curve = BRepAdaptor_Curve(ocp_edge)
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discretizer = GCPnts_TangentialDeflection(curve, angular_deflection, curvature_deflection)
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assert discretizer.NbPoints() > 1, "Edge is too small??"
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# add vertices
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vertices = [
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(v.X(), v.Y(), v.Z())
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for v in (
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discretizer.Value(i) # .Transformed(transformation)
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for i in range(1, discretizer.NbPoints() + 1)
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)
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]
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mgr.add_edge(vertices)
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def _tessellate_vertex(mgr: GLTFMgr, ocp_vertex: TopoDS_Vertex):
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c = Vertex(ocp_vertex).center()
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mgr.add_vertex((c.X, c.Y, c.Z))
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def _hashcode(obj: TopoDS_Shape) -> str:
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"""Utility to compute the hash code of a shape recursively without the need to tessellate it"""
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# NOTE: obj.HashCode(MAX_HASH_CODE) is not stable across different runs of the same program
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# This is best-effort and not guaranteed to be unique
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map_of_shapes = TopTools_IndexedMapOfShape()
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TopExp.MapShapes_s(obj, map_of_shapes)
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hasher = hashlib.md5(usedforsecurity=False)
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for i in range(1, map_of_shapes.Extent() + 1):
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sub_shape = map_of_shapes.FindKey(i)
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sub_data = io.BytesIO()
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TopoDS_Shape.DumpJson(sub_shape, sub_data)
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val = sub_data.getvalue()
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val = re.sub(b'"this": "[^"]*"', b'', val) # Remove memory address
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hasher.update(val)
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return hasher.hexdigest()
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