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yet-another-cad-viewer/yacv_server/tessellate.py
Yeicor 656daf1bf3 work
2024-02-18 23:20:24 +01:00

121 lines
3.7 KiB
Python

import hashlib
import io
import re
import numpy as np
from OCP.BRepAdaptor import BRepAdaptor_Curve
from OCP.GCPnts import GCPnts_TangentialDeflection
from OCP.TopExp import TopExp
from OCP.TopTools import TopTools_IndexedMapOfShape
from OCP.TopoDS import TopoDS_Face, TopoDS_Edge, TopoDS_Shape, TopoDS_Vertex
from build123d import Shape, Vertex
from pygltflib import GLTF2
from gltf import GLTFMgr
# TODO: Migrate to ocp-tessellate to reuse the tessellation logic
def tessellate(
ocp_shape: TopoDS_Shape,
tolerance: float = 1e-3,
angular_tolerance: float = 0.1,
faces: bool = True,
edges: bool = True,
vertices: bool = True,
) -> GLTF2:
"""Tessellate a whole shape into a list of triangle vertices and a list of triangle indices."""
mgr = GLTFMgr()
shape = Shape(ocp_shape)
# Triangulate all faces at the same time
# shape.mesh(tolerance, angular_tolerance)
_tessellate_face(mgr, shape.wrapped)
# Perform tessellation tasks
# if faces:
# for face in shape.faces():
# _tessellate_face(mgr, face.wrapped)
# if edges:
# for edge in shape.edges():
# _tessellate_edge(mgr, edge.wrapped, angular_tolerance, angular_tolerance)
# if vertices:
# for vertex in shape.vertices():
# _tessellate_vertex(mgr, vertex.wrapped)
return mgr.gltf
def _tessellate_face(
mgr: GLTFMgr,
ocp_face: TopoDS_Face,
tolerance: float = 1e-3,
angular_tolerance: float = 0.1
):
face = Shape(ocp_face)
# loc = TopLoc_Location()
# poly = BRep_Tool.Triangulation_s(face.wrapped, loc)
# if poly is None:
# mylogger.logger.warn("No triangulation found for face")
# return GLTF2()
tri_mesh = face.tessellate(tolerance, angular_tolerance)
# Get UV of each face from the parameters
# uv = [
# [v.X(), v.Y()]
# for v in (poly.UVNode(i) for i in range(1, poly.NbNodes() + 1))
# ]
uv = []
vertices = np.array(list(map(lambda v: [v.X, v.Y, v.Z], tri_mesh[0])))
indices = np.array(tri_mesh[1])
tex_coord = np.array(uv)
mgr.add_face(vertices, indices, tex_coord)
def _tessellate_edge(
mgr: GLTFMgr,
ocp_edge: TopoDS_Edge,
angular_deflection: float = 0.1,
curvature_deflection: float = 0.1,
):
curve = BRepAdaptor_Curve(ocp_edge)
discretizer = GCPnts_TangentialDeflection(curve, angular_deflection, curvature_deflection)
assert discretizer.NbPoints() > 1, "Edge is too small??"
# TODO: get and apply transformation??
# add vertices
vertices: list[list[float]] = [
[v.X(), v.Y(), v.Z()]
for v in (
discretizer.Value(i) # .Transformed(transformation)
for i in range(1, discretizer.NbPoints() + 1)
)
]
mgr.add_edge(np.array(vertices))
def _tessellate_vertex(mgr: GLTFMgr, ocp_vertex: TopoDS_Vertex):
c = Vertex(ocp_vertex).center()
mgr.add_vertex(c)
def _hashcode(obj: TopoDS_Shape) -> str:
"""Utility to compute the hash code of a shape recursively without the need to tessellate it"""
# NOTE: obj.HashCode(MAX_HASH_CODE) is not stable across different runs of the same program
# This is best-effort and not guaranteed to be unique
data = io.BytesIO()
map_of_shapes = TopTools_IndexedMapOfShape()
TopExp.MapShapes_s(obj, map_of_shapes)
for i in range(1, map_of_shapes.Extent() + 1):
sub_shape = map_of_shapes.FindKey(i)
sub_data = io.BytesIO()
TopoDS_Shape.DumpJson(sub_shape, sub_data)
val = sub_data.getvalue()
val = re.sub(b'"this": "[^"]*"', b'', val) # Remove memory address
data.write(val)
to_hash = data.getvalue()
return hashlib.md5(to_hash, usedforsecurity=False).hexdigest()