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Refactor MeshHelper #335

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c03b9e2
chore(MeshHelper): inline deflating
isHarryh Jul 20, 2025
83fd2ca
refactor(MeshHelper): optimize array conversion
isHarryh Jul 20, 2025
5419793
refactor(MeshHelper): optimize `get_triangles`
isHarryh Jul 20, 2025
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104 changes: 49 additions & 55 deletions UnityPy/helpers/MeshHelper.py
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@

import math
import struct
from typing import TYPE_CHECKING, List, Optional, Sequence, Tuple, TypeVar, Union, cast
from typing import TYPE_CHECKING, List, Optional, Tuple, Union, cast

from ..classes.generated import (
ChannelInfo,
Expand Down Expand Up @@ -34,12 +34,6 @@
Tuple3f = Tuple[float, float, float]
Tuple4f = Tuple[float, float, float, float]

T = TypeVar("T")


def flat_list_to_tuples(data: Sequence[T], item_size: int) -> List[tuple[T, ...]]:
return [tuple(data[i : i + item_size]) for i in range(0, len(data), item_size)]


def vector_list_to_tuples(
data: Union[List[Vector2f], List[Vector3f], List[Vector4f]],
Expand All @@ -58,14 +52,12 @@ def vector_list_to_tuples(
raise ValueError("Unknown vector type")


def zeros(shape: Union[Tuple[int], Tuple[int, int]]) -> Union[List, List[List]]:
if len(shape) == 1:
return [0] * shape[0]
elif len(shape) == 2:
m, n = shape
return [[0] * n for _ in range(m)]
else:
raise ValueError("Invalid shape")
def lists_to_tuples(data: List[list]) -> List[tuple]:
return [tuple(v) for v in data]


def zeros(m: int, n: int) -> List[list]:
return [[0] * n for _ in range(m)]


def normalize(*vector: float) -> Tuple[float, ...]:
Expand Down Expand Up @@ -234,9 +226,9 @@ def copy_from_mesh(self):

if self.m_BoneWeights is None and mesh.m_Skin:
# BoneInfluence == BoneWeight in terms of usage in UnityPy due to int simplification
self.m_BoneWeights = zeros((len(mesh.m_Skin), 4))
self.m_BoneIndices = zeros((len(mesh.m_Skin), 4))
for skin, indices, weights in zip(mesh.m_Skin, self.m_BoneIndices, self.m_BoneWeights):
boneWeights = zeros(len(mesh.m_Skin), 4)
boneIndices = zeros(len(mesh.m_Skin), 4)
for skin, indices, weights in zip(mesh.m_Skin, boneIndices, boneWeights):
indices[:] = [
skin.boneIndex_0_,
skin.boneIndex_1_,
Expand All @@ -249,6 +241,8 @@ def copy_from_mesh(self):
skin.weight_2_,
skin.weight_3_,
]
self.m_BoneWeights = lists_to_tuples(boneWeights)
self.m_BoneIndices = lists_to_tuples(boneIndices)

def copy_from_spriterenderdata(self):
rd = self.src
Expand Down Expand Up @@ -403,7 +397,10 @@ def read_vertex_data(self, m_Channels: list[ChannelInfo], m_Streams: list[Stream

count = len(componentBytes) // component_byte_size
component_data = struct.unpack(f">{count}{component_dtype}", componentBytes)
component_data = flat_list_to_tuples(component_data, channel_dimension)
component_data = [
tuple(component_data[i : i + channel_dimension])
for i in range(0, len(component_data), channel_dimension)
]

self.assign_channel_vertex_data(chn, component_data)

Expand Down Expand Up @@ -483,10 +480,11 @@ def get_channel_component_size(self, m_Channel: ChannelInfo):
def decompress_compressed_mesh(self):
# TODO: m_Triangles????

# Vertex
version = self.version
assert isinstance(self.src, Mesh)
m_CompressedMesh = self.src.m_CompressedMesh

# Vertex
self.m_VertexCount = m_VertexCount = m_CompressedMesh.m_Vertices.m_NumItems // 3

if m_CompressedMesh.m_Vertices.m_NumItems > 0:
Expand Down Expand Up @@ -543,8 +541,8 @@ def decompress_compressed_mesh(self):
normalData = unpack_floats(m_CompressedMesh.m_Normals, shape=(2,))
signs = unpack_ints(m_CompressedMesh.m_NormalSigns)

self.m_Normals = zeros((self.m_VertexCount, 3))
for srcNrm, sign, dstNrm in zip(normalData, signs, self.m_Normals):
normals = zeros(self.m_VertexCount, 3)
for srcNrm, sign, dstNrm in zip(normalData, signs, normals):
x, y = srcNrm
zsqr = 1 - x * x - y * y
if zsqr >= 0:
Expand All @@ -555,13 +553,15 @@ def decompress_compressed_mesh(self):
dstNrm[:] = normalize(x, y, z)
if sign == 0:
dstNrm[2] *= -1
self.m_Normals = lists_to_tuples(normals)

# Tangent
if m_CompressedMesh.m_Tangents.m_NumItems > 0:
tangentData = unpack_floats(m_CompressedMesh.m_Tangents, shape=(2,))
signs = unpack_ints(m_CompressedMesh.m_TangentSigns, shape=(2,))
self.m_Tangents = zeros((self.m_VertexCount, 4))
for srcTan, (sign_z, sign_w), dstTan in zip(tangentData, signs, self.m_Tangents):

tangents = zeros(self.m_VertexCount, 4)
for srcTan, (sign_z, sign_w), dstTan in zip(tangentData, signs, tangents):
x, y = srcTan
zsqr = 1 - x * x - y * y
z = 0
Expand All @@ -574,6 +574,7 @@ def decompress_compressed_mesh(self):
z = -z
w = 1.0 if sign_w > 0 else -1.0
dstTan[:] = x, y, z, w
self.m_Tangents = lists_to_tuples(tangents)

# FloatColor
if version[0] >= 5: # 5.0 and up
Expand All @@ -590,14 +591,14 @@ def decompress_compressed_mesh(self):
j = 0
sum = 0

self.m_BoneWeights = zeros((self.m_VertexCount, 4))
self.m_BoneIndices = zeros((self.m_VertexCount, 4))
boneWeights = zeros(self.m_VertexCount, 4)
boneIndices = zeros(self.m_VertexCount, 4)

boneIndicesIterator = iter(boneIndicesData)
for weight, boneIndex in zip(weightsData, boneIndicesIterator):
# read bone index and weight
self.m_BoneWeights[vertexIndex][j] = weight
self.m_BoneIndices[vertexIndex][j] = boneIndex
boneWeights[vertexIndex][j] = weight
boneIndices[vertexIndex][j] = boneIndex

j += 1
sum += weight
Expand All @@ -613,13 +614,16 @@ def decompress_compressed_mesh(self):
# we read three weights, but they don't add up to one. calculate the fourth one, and read
# missing bone index. continue with next vertex.
elif j == 3: #
self.m_BoneWeights[vertexIndex][j] = 1 - sum
self.m_BoneIndices[vertexIndex][j] = next(boneIndicesIterator)
boneWeights[vertexIndex][j] = 1 - sum
boneIndices[vertexIndex][j] = next(boneIndicesIterator)

vertexIndex += 1
j = 0
sum = 0

self.m_BoneWeights = lists_to_tuples(boneWeights)
self.m_BoneIndices = lists_to_tuples(boneIndices)

# IndexBuffer
if m_CompressedMesh.m_Triangles.m_NumItems > 0: #
self.m_IndexBuffer = unpack_ints(m_CompressedMesh.m_Triangles)
Expand All @@ -638,10 +642,10 @@ def decompress_compressed_mesh(self):

def get_triangles(self) -> List[List[Tuple[int, ...]]]:
assert self.m_IndexBuffer is not None
assert self.src.m_SubMeshes is not None

submeshes: List[List[Tuple[int, ...]]] = []

assert self.src and self.src.m_SubMeshes is not None, "No submesh data!"
for m_SubMesh in self.src.m_SubMeshes:
firstIndex = m_SubMesh.firstByte // 2
if not self.m_Use16BitIndices:
Expand All @@ -650,41 +654,31 @@ def get_triangles(self) -> List[List[Tuple[int, ...]]]:
indexCount = m_SubMesh.indexCount
topology = m_SubMesh.topology

triangles: List[Tuple[int, ...]]
triangles: List[Tuple[int, ...]] = []

if topology == MeshTopology.Triangles:
triangles = self.m_IndexBuffer[firstIndex : firstIndex + indexCount] # type: ignore
triangles = [triangles[i : i + 3] for i in range(0, len(triangles), 3)] # type: ignore
elif self.version[0] < 4 or topology == MeshTopology.TriangleStrip: # TriangleStrip
# todo: use as_strided, then fix winding, finally remove degenerates
triIndex = 0
triangles = [None] * (indexCount - 2) # type: ignore

for i in range(indexCount - 2):
a, b, c = self.m_IndexBuffer[firstIndex + i : firstIndex + i + 3]
for i in range(firstIndex, firstIndex + indexCount, 3):
triangles.append(tuple(self.m_IndexBuffer[i : i + 3]))

elif self.version[0] < 4 or topology == MeshTopology.TriangleStrip:
for i in range(firstIndex, firstIndex + indexCount - 2):
a, b, c = self.m_IndexBuffer[i : i + 3]
# skip degenerates
if a == b or a == c or b == c:
continue

# do the winding flip-flop of strips
if i & 1:
triangles[triIndex] = b, a, c
if (i - firstIndex) & 1:
triangles.append((b, a, c))
else:
triangles[triIndex] = a, b, c
triIndex += 1

triangles = triangles[:triIndex]
triangles.append((a, b, c))
m_SubMesh.indexCount = len(triangles) * 3

elif topology == MeshTopology.Quads:
# one quad is two triangles, so // 4 * 2 = // 2
# TODO: use as_strided
triangles = [None] * (indexCount // 2) # type: ignore
triIndex = 0
for i in range(firstIndex, firstIndex + indexCount, 4):
a, b, c, d = self.m_IndexBuffer[i : i + 4]
triangles[triIndex] = a, b, c
triangles[triIndex + 1] = a, c, d
triIndex += 2
triangles.append((a, b, c))
triangles.append((a, c, d))

else:
raise ValueError("Failed getting triangles. Submesh topology is lines or points.")

Expand Down
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