整理文件夹及架构，加入打印机页面，octo反代有问题

app/utils/stl_merger.py

@@ -0,0 +1,107 @@
+import struct
+import math
+import os
+
+def merge_stls(input_files, output_path):
+    try:
+        from stl import mesh
+        import numpy as np
+        
+        meshes = []
+        for path, matrix in input_files:
+            try:
+                # 重新换回轻量级的 numpy-stl 以防内存溢出 (OOM)
+                m = mesh.Mesh.from_file(path)
+                
+                mat = np.array(matrix, dtype=np.float64).reshape((4, 4)).T
+                
+                vectors = m.vectors.reshape(-1, 3)
+                hom_vectors = np.hstack((vectors, np.ones((len(vectors), 1), dtype=np.float32)))
+                transformed = (mat @ hom_vectors.T).T
+                m.vectors = transformed[:, :3].reshape(-1, 3, 3)
+                
+                # 检测缩放矩阵是否引发镜像翻转 (行列式为负数)
+                det = np.linalg.det(mat[:3, :3])
+                if det < 0:
+                    # 发生镜像反转，不仅法线会反向，三角形三个顶点的顺逆时针（Winding Order）也会错乱
+                    # 强行交换每个三角形的顶点2和顶点3以纠正渲染正反面
+                    m.vectors[:, [1, 2]] = m.vectors[:, [2, 1]]
+                
+                m.update_normals()
+                meshes.append(m)
+            except Exception as e:
+                print(f"Error processing path {path} with stl mesh: {e}")
+                
+        if not meshes:
+            return
+            
+        if len(meshes) == 1:
+            meshes[0].save(output_path)
+            return
+            
+        merged_data = np.concatenate([m.data for m in meshes])
+        merged_mesh = mesh.Mesh(merged_data)
+        merged_mesh.save(output_path)
+        return
+        
+    except Exception as e:
+        print(f"Mesh fast-merge failed: {e}. Falling back to struct parsing.")
+
+    # Extreme fallback just in case no stl libraries work
+    total_faces = 0
+    meshes_data = []
+
+    for path, matrix in input_files:
+        with open(path, 'rb') as f:
+            f.read(80)
+            faces = struct.unpack('<I', f.read(4))[0]
+            data = f.read(faces * 50)
+            
+            def apply_m(_x, _y, _z):
+                w = _x * matrix[3] + _y * matrix[7] + _z * matrix[11] + matrix[15]
+                nx = (_x * matrix[0] + _y * matrix[4] + _z * matrix[8] + matrix[12]) / w
+                ny = (_x * matrix[1] + _y * matrix[5] + _z * matrix[9] + matrix[13]) / w
+                nz = (_x * matrix[2] + _y * matrix[6] + _z * matrix[10] + matrix[14]) / w
+                return nx, ny, nz
+            
+            new_data = bytearray(faces * 50)
+            src_offset = 0
+            dst_offset = 0
+            for _ in range(faces):
+                n_x, n_y, n_z, v1x, v1y, v1z, v2x, v2y, v2z, v3x, v3y, v3z, attr = struct.unpack_from('<12fH', data, src_offset)
+                
+                nv1x, nv1y, nv1z = apply_m(v1x, v1y, v1z)
+                nv2x, nv2y, nv2z = apply_m(v2x, v2y, v2z)
+                nv3x, nv3y, nv3z = apply_m(v3x, v3y, v3z)
+                
+                # Recalculate normal properly using cross product to fix flipped/sheared surfaces
+                Ux = nv2x - nv1x
+                Uy = nv2y - nv1y
+                Uz = nv2z - nv1z
+                Vx = nv3x - nv1x
+                Vy = nv3y - nv1y
+                Vz = nv3z - nv1z
+                
+                nnx = Uy * Vz - Uz * Vy
+                nny = Uz * Vx - Ux * Vz
+                nnz = Ux * Vy - Uy * Vx
+                
+                l = math.sqrt(nnx**2 + nny**2 + nnz**2)
+                if l > 1e-8:
+                    nnx, nny, nnz = nnx/l, nny/l, nnz/l
+                else:
+                    nnx, nny, nnz = 0.0, 0.0, 0.0
+                
+                struct.pack_into('<12fH', new_data, dst_offset, nnx, nny, nnz, nv1x, nv1y, nv1z, nv2x, nv2y, nv2z, nv3x, nv3y, nv3z, attr)
+                src_offset += 50
+                dst_offset += 50
+                
+            meshes_data.append(new_data)
+            total_faces += faces
+            
+    with open(output_path, 'wb') as f:
+        f.write(b'\0' * 80)
+        f.write(struct.pack('<I', total_faces))
+        for d in meshes_data:
+            f.write(d)
+