HDK
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends Macros Groups Pages
collectionCache.h
Go to the documentation of this file.
1 //
2 // Copyright 2018 Pixar
3 //
4 // Licensed under the Apache License, Version 2.0 (the "Apache License")
5 // with the following modification; you may not use this file except in
6 // compliance with the Apache License and the following modification to it:
7 // Section 6. Trademarks. is deleted and replaced with:
8 //
9 // 6. Trademarks. This License does not grant permission to use the trade
10 // names, trademarks, service marks, or product names of the Licensor
11 // and its affiliates, except as required to comply with Section 4(c) of
12 // the License and to reproduce the content of the NOTICE file.
13 //
14 // You may obtain a copy of the Apache License at
15 //
16 // http://www.apache.org/licenses/LICENSE-2.0
17 //
18 // Unless required by applicable law or agreed to in writing, software
19 // distributed under the Apache License with the above modification is
20 // distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
21 // KIND, either express or implied. See the Apache License for the specific
22 // language governing permissions and limitations under the Apache License.
23 //
24 #ifndef PXR_USD_IMAGING_USD_IMAGING_COLLECTION_CACHE_H
25 #define PXR_USD_IMAGING_USD_IMAGING_COLLECTION_CACHE_H
26 
27 /// \file usdImaging/collectionCache.h
28 
29 #include "pxr/pxr.h"
32 
33 #include <hboost/noncopyable.hpp>
34 #include <tbb/concurrent_unordered_map.h>
35 #include <tbb/concurrent_queue.h>
36 #include <unordered_map>
37 
39 
40 /// \class UsdImaging_CollectionCache
41 ///
42 /// UsdImaging_CollectionCache provides a cache of Usd collections
43 /// discovered in the scene. It associates the collection paths
44 /// (UsdCollectionAPI::GetCollectionPath) with the computed
45 /// membership query (UsdCollectionAPI::ComputeMembershipQuery).
46 ///
47 /// For efficiency, it groups collections into equivalence
48 /// classes based on the computed query. Collections that yield
49 /// equivalent queries are merged. Each unique query is assigned
50 /// an identifier token.
51 ///
52 /// This cache is used to track the collections used for linking
53 /// UsdLux lights/shadows/filters to geometry.
54 ///
55 /// As an optimization, the query that includes everything is
56 /// treated as a special case and given the empty id, TfToken().
57 ///
58 class UsdImaging_CollectionCache : hboost::noncopyable {
59 public:
60  /// Query is the MembershipQuery computed from a collection's state.
62 
63  /// Computes the membership query from the current state of the
64  /// given collection, and establishes a cache entry. If a
65  /// prior entry existed for the collection at this path,
66  /// it is removed first.
67  TfToken UpdateCollection(UsdCollectionAPI const& collection);
68 
69  /// Remove any cached entry for the given collection.
70  /// Does nothing if no cache entry exists.
71  void RemoveCollection(UsdCollectionAPI const& collection);
72 
73  /// Return the cached entry for the given collection.
74  TfToken
75  GetIdForCollection(UsdCollectionAPI const& collection);
76 
77  /// Return a list of identifiers of all collections that contain
78  // the given path.
81 
82 private:
83  // The cache boils down to tracking the correspondence of
84  // collection paths, their computed queries, and the id
85  // assigned to each unique query:
86  //
87  // CollectionPath <=> MembershipQuery <=> AssignedId
88  //
89  // In this scheme, the assigned id provides a compact but
90  // potentially human-meaningful reference to the query,
91  // which we can pass to the renderer.
92  //
93  std::unordered_map<Query, TfToken, Query::Hash> _idForQuery;
94  std::unordered_map<TfToken, Query, TfToken::HashFunctor> _queryForId;
95  std::unordered_map<SdfPath, TfToken, SdfPath::Hash> _idForPath;
96  std::unordered_map<Query, SdfPathSet, Query::Hash> _pathsForQuery;
97 
98  std::mutex _mutex;
99 };
100 
101 
103 
104 #endif // PXR_USD_IMAGING_USD_IMAGING_COLLECTION_CACHE_H
Represents a flattened view of a collection. For more information about collections, please see UsdCollectionAPI as a way to encode and retrieve a collection from scene description. A UsdCollectionMembershipQuery object can be used to answer queries about membership of paths in the collection efficiently.
Definition: token.h:87
void RemoveCollection(UsdCollectionAPI const &collection)
VtArray< TfToken > ComputeCollectionsContainingPath(SdfPath const &path) const
Return a list of identifiers of all collections that contain.
Definition: path.h:288
GLsizei const GLchar *const * path
Definition: glew.h:6461
TfToken GetIdForCollection(UsdCollectionAPI const &collection)
Return the cached entry for the given collection.
PXR_NAMESPACE_CLOSE_SCOPE PXR_NAMESPACE_OPEN_SCOPE
Definition: path.h:1346
UsdCollectionAPI::MembershipQuery Query
Query is the MembershipQuery computed from a collection's state.
#define PXR_NAMESPACE_CLOSE_SCOPE
Definition: pxr.h:91
TfToken UpdateCollection(UsdCollectionAPI const &collection)