1 files changed, 113 insertions, 0 deletions
diff --git a/mesh.py b/mesh.py
new file mode 100644
index 0000000..a4b9048
--- /dev/null
+++ b/mesh.py
@@ -0,0 +1,113 @@
+import numpy as np
+import string
+import struct
+
+class Mesh(object):
+    def __init__(self, vertices, triangles):
+        vertices = np.asarray(vertices, dtype=float)
+        triangles = np.asarray(triangles, dtype=int)
+
+        if len(vertices.shape) != 2 or vertices.shape[1] != 3:
+            raise ValueError('shape mismatch')
+
+        if len(triangles.shape) != 2 or triangles.shape[1] != 3:
+            raise ValueError('shape mismatch')
+
+        if (triangles < 0).any():
+            raise ValueError('indices in `triangles` must be positive.')
+
+        if (triangles >= len(vertices)).any():
+            raise ValueError('indices in `triangles` must be less than the '
+                             'length of the vertex array.')
+
+        self.vertices = vertices
+        self.triangles = triangles
+
+    def build(self):
+        return self.vertices[self.triangles]
+
+    def __add__(self, other):
+        vertices = np.concatenate((self.vertices, other.vertices))
+        triangles = np.concatenate((self.triangles, other.triangles+len(self.vertices)))
+
+        return Mesh(vertices, triangles)
+
+    def __len__(self):
+        return len(self.triangles)
+
+def mesh_from_stl(filename):
+    f = open(filename)
+    buf = f.read(200)
+    f.close()
+
+    for char in buf:
+        if char not in string.printable:
+            return mesh_from_binary_stl(filename)
+
+    return mesh_from_ascii_stl(filename)
+
+def mesh_from_ascii_stl(filename):
+    f = open(filename)
+
+    vertices = []
+    triangles = []
+    vertex_map = {}
+
+    while True:
+        line = f.readline()
+
+        if line == '':
+            break
+
+        if not line.strip().startswith('vertex'):
+            continue
+
+        triangle = [None]*3
+        for i in range(3):
+            vertex = tuple([float(s) for s in line.strip().split()[1:]])
+
+            if vertex not in vertex_map:
+                vertices.append(vertex)
+                vertex_map[vertex] = len(vertices) - 1
+
+            triangle[i] = vertex_map[vertex]
+
+            if i < 3:
+                line = f.readline()
+
+        triangles.append(triangle)
+
+    f.close()
+
+    return Mesh(np.array(vertices), np.array(triangles, dtype=np.uint32))
+
+def mesh_from_binary_stl(filename):
+    f = open(filename)
+
+    vertices = []
+    triangles = []
+    vertex_map = {}
+
+    f.read(80)
+    ntriangles = struct.unpack('<I', f.read(4))[0]
+
+    for i in range(ntriangles):
+        f.read(12)
+
+        triangle = [None]*3
+        for j in range(3):
+            vertex = tuple(struct.unpack('<fff', f.read(12)))
+
+            if vertex not in vertex_map:
+                vertices.append(vertex)
+                vertex_map[vertex] = len(vertices) - 1
+
+            triangle[j] = vertex_map[vertex]
+
+        triangles.append(triangle)
+
+        f.read(2)
+
+    f.close()
+
+    return Mesh(np.array(vertices), np.array(triangles, dtype=np.uint32))