Fix stl parser bug

zigsdof/src/stl.zig

@@ -81,11 +81,12 @@ pub const Mesh = struct {
                     indices[i] = new_idx;
                 }
             }
+            // skip attribute bytes
+            offset += 2;
             try triangle_vertices.append(allocator, indices);
             try triangle_normals.append(allocator, normal);
         }
 
-        std.debug.print("{}", .{vertices});
         return .{
             .triangle_vertices = triangle_vertices,
             .triangle_normals = triangle_normals,
@@ -150,4 +151,16 @@ test "Test binary stl is parsed correctly" {
         vec3.Vec3F64.init(1, 1, 1),
         1e-12,
     ));
+
+    try std.testing.expect(vec3.vec3ApproxEq(
+        mesh.triangle_normals.items[0],
+        vec3.Vec3F64.init(1, 0, 0),
+        1e-12,
+    ));
+
+    try std.testing.expect(vec3.vec3ApproxEq(
+        mesh.triangle_normals.items[1],
+        vec3.Vec3F64.init(0, -0.7071067690849304, 0.7071067690849304),
+        1e-12,
+    ));
 }