代码有未定义的get_vertices:import math
from collections import defaultdict
from pathlib import Path
def process_folder(input_dir, output_dir):
"""保持原有文件夹处理逻辑不变"""
Path(output_dir).mkdir(parents=True, exist_ok=True)
valid_extensions = {'.txt', '.obj', '.geo'}
for input_path in Path(input_dir).rglob('*'):
if input_path.is_dir() or input_path.suffix.lower() not in valid_extensions:
continue
relative_path = input_path.relative_to(input_dir)
output_path = Path(output_dir) / relative_path.with_name(f"{input_path.stem}_mesh.obj")
output_path.parent.mkdir(parents=True, exist_ok=True)
try:
process_single_file(input_path, output_path)
print(f"成功处理：{input_path} -> {output_path}")
except Exception as e:
print(f"处理失败：{input_path}\n错误详情：{str(e)}\n{'='*50}")
def process_single_file(input_path, output_path):
"""保持原有单文件处理逻辑不变"""
with open(input_path, 'r') as f:
raw_lines = [line.strip() for line in f if line.strip()]
vertices, lines = parse_input_data(raw_lines)
obj_lines = enhanced_convert_lines_to_mesh(vertices, lines)
with open(output_path, 'w') as f:
f.write("\n".join(obj_lines))
def parse_input_data(raw_lines):
"""保持原有数据解析逻辑不变"""
vertices = []
lines = []
for line in raw_lines:
if line.startswith('#') or not line.split():
continue
parts = line.split()
try:
if parts[0].lower() == 'v':
vertices.append(' '.join(parts[1:4]))
elif parts[0].lower() == 'l':
start = int(parts[1]) - 1
end = int(parts[2]) - 1
lines.append((start, end))
except (IndexError, ValueError) as e:
raise ValueError(f"解析错误：{line}") from e
return vertices, lines
def enhanced_convert_lines_to_mesh(vertex_data, line_data):
"""增强型网格生成算法"""
# 构建邻接表并缓存坐标
adj, coords = build_adjacency_with_coords(line_data, vertex_data)
# 第一步：查找严格闭合的平面多边形
planar_faces = find_planar_faces(adj, coords)
# 第二步：处理非闭合结构
edge_faces = process_open_structures(adj, coords)
# 合并结果并去重
all_faces = deduplicate_faces(planar_faces + edge_faces)
return generate_obj_content(vertex_data, all_faces)
def build_adjacency_with_coords(line_data, vertex_data):
"""构建邻接表并缓存坐标"""
adj = defaultdict(set)
coord_cache = {}
for idx in range(len(vertex_data)):
parts = vertex_data[idx].split()
coord_cache[idx] = tuple(map(float, parts))
for s, e in line_data:
adj[s].add(e)
adj[e].add(s)
return adj, coord_cache
def find_planar_faces(adj, coord_cache, max_length=6):
"""查找平面多边形"""
def dfs(current, path, edges):
cycles = []
if len(path) > 2 and current == path[0]:
cycle = path[:-1] # 去除重复起点
if validate_planar_cycle(cycle, coord_cache):
return [cycle]
return []
if len(path) >= max_length:
return []
for neighbor in adj[current]:
edge = tuple(sorted((current, neighbor)))
if edge not in edges:
new_edges = edges.copy()
new_edges.add(edge)
cycles += dfs(neighbor, path + [neighbor], new_edges)
return cycles
seen = set()
planar_faces = []
for start in adj:
for cycle in dfs(start, [start], set()):
normalized = normalize_cycle(cycle)
if normalized not in seen:
seen.add(normalized)
planar_faces.extend(triangulate_planar_face(normalized, coord_cache))
return planar_faces
def validate_planar_cycle(cycle, coord_cache, tolerance=1e-3):
"""验证多边形平面性（放宽容差）"""
if len(cycle) < 3:
return False
# 计算平均法线
normals = []
for i in range(len(cycle)):
a = coord_cache[cycle[i-2]]
b = coord_cache[cycle[i-1]]
c = coord_cache[cycle[i]]
normals.append(calculate_normal(a, b, c))
# 检查法线一致性
ref_normal = normals[0]
for n in normals[1:]:
if angle_between(ref_normal, n) > math.radians(5): # 允许5度偏差
return False
return True
def triangulate_planar_face(cycle, coord_cache):
"""平面多边形三角剖分"""
try:
# 将三维坐标投影到二维平面
points_3d = [coord_cache[v] for v in cycle]
normal = calculate_normal(*points_3d[:3])
basis = create_projection_basis(normal)
points_2d = [project_point(p, basis) for p in points_3d]
# 执行二维耳切法
triangles = ear_clipping_2d(points_2d)
return [(cycle[i], cycle[j], cycle[k]) for i, j, k in triangles]
except:
return []
def process_open_structures(adj, coord_cache):
"""处理开放式结构（线段连接）"""
faces = []
visited = set()
# 查找所有三角形结构
for a in adj:
for b in adj[a]:
if b in visited:
continue
for c in adj[b]:
if c in adj[a] and c != a and c != b:
# 检查是否形成有效三角形
if validate_triangle(a, b, c, coord_cache):
faces.append((a, b, c))
visited.update({a, b, c})
return faces
def validate_triangle(a, b, c, coord_cache):
"""验证三角形有效性"""
try:
p1 = coord_cache[a]
p2 = coord_cache[b]
p3 = coord_cache[c]
# 检查面积
area = 0.5 * math.sqrt(sum(x**2 for x in calculate_normal(p1, p2, p3)))
return area > 1e-6
except:
return False
# ---------- 几何计算辅助函数 ----------
def calculate_normal(a, b, c):
"""计算法线向量"""
v1 = [b[i]-a[i] for i in range(3)]
v2 = [c[i]-a[i] for i in range(3)]
return cross_product(v1, v2)
def cross_product(v1, v2):
return [
v1[1]*v2[2] - v1[2]*v2[1],
v1[2]*v2[0] - v1[0]*v2[2],
v1[0]*v2[1] - v1[1]*v2[0]
]
def angle_between(v1, v2):
"""计算两向量夹角"""
dot = sum(x*y for x, y in zip(v1, v2))
mag1 = math.sqrt(sum(x**2 for x in v1))
mag2 = math.sqrt(sum(y**2 for y in v2))
return math.acos(dot/(mag1*mag2 + 1e-9))
def create_projection_basis(normal):
"""创建投影坐标系"""
axis_x = [1, 0, 0] if abs(normal[1]) > 0.5 else [0, 1, 0]
tangent = cross_product(normal, axis_x)
binormal = cross_product(normal, tangent)
return (tangent, binormal)
def project_point(p, basis):
"""三维坐标投影到二维平面"""
return (
p[0]*basis[0][0] + p[1]*basis[0][1] + p[2]*basis[0][2],
p[0]*basis[1][0] + p[1]*basis[1][1] + p[2]*basis[1][2]
)
def ear_clipping_2d(points):
"""二维耳切法实现"""
indices = list(range(len(points)))
triangles = []
while len(indices) > 3:
ear_found = False
for i in range(len(indices)):
a, b, c = get_vertices(indices, i)
if is_ear(a, b, c, points, indices):
triangles.append((a, b, c))
del indices[i]
ear_found = True
break
if not ear_found:
break
if len(indices) == 3:
triangles.append(tuple(indices))
return triangles
def is_ear(a, b, c, points, indices):
"""检查是否为耳朵"""
if not is_convex(points[a], points[b], points[c]):
return False
return not any(point_in_triangle(points[i], points[a], points[b], points[c])
for i in indices if i not in {a, b, c})
def point_in_triangle(p, a, b, c, tol=1e-6):
"""精确点包含检查"""
area = triangle_area(a, b, c)
return abs(area - (triangle_area(a, b, p) +
triangle_area(b, c, p) +
triangle_area(c, a, p))) < tol
def triangle_area(a, b, c):
"""计算三角形面积"""
return 0.5 * abs(
(b[0]-a[0])*(c[1]-a[1]) -
(c[0]-a[0])*(b[1]-a[1])
)
# ---------- 辅助函数 ----------
def normalize_cycle(cycle):
"""优化的环标准化"""
min_val = min(cycle)
rotations = [cycle[i:] + cycle[:i] for i, v in enumerate(cycle) if v == min_val]
reversed_rot = [list(reversed(r)) for r in rotations]
all_candidates = rotations + reversed_rot
return min(all_candidates)
def deduplicate_faces(faces):
"""面片去重"""
seen = set()
unique = []
for f in faces:
key = tuple(sorted(f))
if key not in seen and len(set(key)) == 3:
seen.add(key)
unique.append(f)
return unique
def generate_obj_content(vertex_data, faces):
"""生成OBJ文件内容"""
output = ["# Generated Mesh"]
output += [f"v {v}" for v in vertex_data]
output.append("\n# Faces")
output += [f"f {' '.join(str(v+1) for v in f)}" for f in faces]
return output
if __name__ == "__main__":
INPUT_DIR = "D:/idmdownload/Compressed/Tallinn/train/wireframe"
OUTPUT_DIR = "D:/idmdownload/Compressed/Tallinn/train/mesh"
if not Path(INPUT_DIR).exists():
raise FileNotFoundError(f"输入目录不存在：{INPUT_DIR}")
if INPUT_DIR == OUTPUT_DIR:
raise ValueError("输入输出目录不能相同")
try:
process_folder(INPUT_DIR, OUTPUT_DIR)
print(f"\n处理完成！输出文件数：{len(list(Path(OUTPUT_DIR).rglob('*.obj')))}")
except KeyboardInterrupt:
print("\n操作已中断")
最新发布
本文介绍了几种计算二维图形面积的方法，包括三角形和多边形的古代和现代算法。对于三角形，给出了直接公式和向量计算方式；对于多边形，则通过分解为多个三角形并求和的方式给出解决方案。
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