Cristian Balas
121 lines
4.4 KiB
Python
121 lines
4.4 KiB
Python
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from mtl_file_collection import MtlFileCollection
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import os
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class ObjFile(object):
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def __init__(self, file_path) -> None:
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self.logged_unsupported = set()
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self.mtl_files = MtlFileCollection(os.path.dirname(file_path))
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self.crt_object = ''
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self.crt_mtl = ''
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self.vertices = []
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self.vertex_colors = []
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self.faces = []
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# Constructed in the post-process phase
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self.objects = {}
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with open(file_path, 'r') as f:
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while True:
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line = f.readline()
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if not line:
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break
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if not line.strip() or line.startswith('#'):
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continue
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parts = line.strip().split(' ')
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if parts[0] == 'v':
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self.on_v(parts[1:])
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elif parts[0] == 'l':
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self.on_l(parts[1:])
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elif parts[0] == 'f':
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self.on_f(parts[1:])
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elif parts[0] == 'mtllib':
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self.mtl_files.mtllib(' '.join(parts[1:]))
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elif parts[0] == 'usemtl':
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self.crt_mtl = ' '.join(parts[1:])
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elif parts[0] == 'o':
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self.crt_object = parts[1]
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else:
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if parts[0] not in self.logged_unsupported:
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print('Unsupported OBJ directive: ' + parts[0])
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self.logged_unsupported.add(parts[0])
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self.post_process()
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def flatten_vertices(self):
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return [coord for point in self.vertices for coord in point]
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def on_v(self, params):
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r, g, b = None, None, None
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w = 1.0
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if len(params) == 3:
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x, y, z = [float(param) for param in params]
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if len(params) == 4:
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x, y, z, w = [float(param) for param in params]
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if len(params) == 6:
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x, y, z, r, g, b = [float(param) for param in params]
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self.vertices.append((x, z, y))
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if r is None or g is None or b is None:
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self.vertex_colors.append(None)
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else:
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self.vertex_colors.append((r, g, b))
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def on_l(self, params):
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# TODO: handle lines
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pass
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def on_f(self, params):
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indices = []
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for param in params:
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# TODO: use texture coordinate index / use vertex normal index?
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v_index = int(param.split('/')[0])
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# If an index is positive then it refers to the offset in that vertex list, starting at 1.
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# If an index is negative then it relatively refers to the end of the vertex list, -1 referring to the last element.
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if v_index > 0:
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v_index -= 1
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indices.append(v_index)
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self.faces.append({
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'indices': indices,
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'object': self.crt_object,
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'mtl': self.crt_mtl
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})
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def post_process(self):
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# Step 1: group into object_id/material_id/[faces_with_global_indices]
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objects = {}
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for face in self.faces:
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if face['object'] not in objects:
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objects[face['object']] = {}
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obj = objects[face['object']]
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if face['mtl'] not in obj:
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obj[face['mtl']] = []
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obj[face['mtl']].append(face['indices'])
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# Step 2: construct final structure: object_id / [{material, local_vertices, vertex_colors, faces_with_local_indices}]
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for object in objects:
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self.objects[object] = []
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for mtl in objects[object].keys():
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material = self.mtl_files.get_material(mtl)
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vertices = []
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vertex_colors = []
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faces = []
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v_global2local_id = {}
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for face in objects[object][mtl]:
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for global_v in face:
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if global_v not in v_global2local_id:
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v_global2local_id[global_v] = len(vertices)
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vertices.append(self.vertices[global_v])
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vertex_colors.append(self.vertex_colors[global_v])
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faces.append([v_global2local_id[global_id] for global_id in face])
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self.objects[object].append({
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'material': material,
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'vertices': vertices,
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'vertex_colors': vertex_colors,
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'faces': faces
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})
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