rewrite

obj.py

@@ -0,0 +1,102 @@
+from dataclasses import dataclass
+
+@dataclass
+class Position:
+    x: float
+    y: float
+    z: float
+
+@dataclass
+class UV:
+    x: float
+    y: float
+
+@dataclass
+class Vertex:
+    pos: Position
+    uv: UV
+
+@dataclass
+class VertexID:
+    pos: int
+    uv: int
+
+class Obj:
+    """
+    parsed obj file
+
+    positions: list[Position]
+    uvs: list[UV]
+    faces: list[list[VertexID]]
+    """
+    def __init__(self, filename):
+        file = open(filename, "r", encoding="utf-8")
+        self.parse(file)
+        file.close()
+    def parse(self, file):
+        self.positions: list[Position] = []
+        self.uvs: list[UV] = []
+        self.faces: list[list[VertexID]] = []
+        for line in file:
+            #vertices
+            if line.startswith("v "):
+                cleaned = line[2:].split()
+                self.positions.append(Position(*(float(num) for num in cleaned)))
+            #uvs
+            elif line.startswith("vt "):
+                cleaned = line[3:].split()
+                self.uvs.append(UV(*(float(num) for num in cleaned)))
+            #faces
+            elif line.startswith("f "):
+                face = line[2:].split()
+                verts = []
+                for vert in face:
+                    ids = vert.split("/")
+                    pos = int(ids[0]) - 1
+                    uv = int(ids[1]) - 1
+                    verts.append(VertexID(pos, uv))
+                self.faces.append(verts)
+        return self
+
+class Objs():
+    """
+    collection of indexed obj data
+
+    positions: list[Position]
+    uvs: list[UV]
+    faces: list[list[VertexID]]
+
+    add(Obj) -> Objs
+    """
+    def __init__(self):
+        self.positions: list[Position] = []
+        self.uvs: list[UV] = []
+        self.vertices: list[VertexID] = []
+        self.mem = {"pos":{}, "uv":{}, "vert":{}}
+    def add(self, obj: Obj):
+        for face in obj.faces:
+            for vertid in face:
+                self.indexvert(obj, vertid)
+            if len(face) == 3:
+                self.indexvert(obj, face[1])
+        return self
+    def indexvert(self, obj: Obj, vertid: VertexID):
+        pos = obj.positions[vertid.pos]
+        uv = obj.uvs[vertid.uv]
+        posh = str(pos)
+        uvh = str(uv)
+        v = VertexID(0, 0)
+        try:
+            v.pos = self.mem['pos'][posh]
+        except:
+            v.pos = len(self.positions)
+            self.mem["pos"][posh] = len(self.positions)
+            self.positions.append(pos)
+        try:
+            v.uv = self.mem['uv'][uvh]
+        except:
+            v.uv = len(self.uvs)
+            self.mem["uv"][uvh] = len(self.uvs)
+            self.uvs.append(uv)
+
+        self.vertices.append(v)