xformCache.h

//
// Copyright 2016 Pixar
//
// Licensed under the Apache License, Version 2.0 (the "Apache License")
// with the following modification; you may not use this file except in
// compliance with the Apache License and the following modification to it:
// Section 6. Trademarks. is deleted and replaced with:
//
// 6. Trademarks. This License does not grant permission to use the trade
//    names, trademarks, service marks, or product names of the Licensor
//    and its affiliates, except as required to comply with Section 4(c) of
//    the License and to reproduce the content of the NOTICE file.
//
// You may obtain a copy of the Apache License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the Apache License with the above modification is
// distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the Apache License for the specific
// language governing permissions and limitations under the Apache License.
//
#ifndef PXR_USD_USD_GEOM_XFORM_CACHE_H
#define PXR_USD_USD_GEOM_XFORM_CACHE_H

#include "pxr/pxr.h"
#include "pxr/usd/usdGeom/api.h"
#include "pxr/usd/usd/attributeQuery.h"
#include "pxr/usd/usd/prim.h"

#include "pxr/usd/usdGeom/xformable.h"

#include "pxr/base/gf/matrix4d.h"
#include "pxr/base/tf/hash.h"
#include "pxr/base/tf/hashmap.h"
#include "pxr/base/tf/token.h"

PXR_NAMESPACE_OPEN_SCOPE


class UsdGeomXformCache
{
public:
    USDGEOM_API
    explicit UsdGeomXformCache(const UsdTimeCode time);

    USDGEOM_API
    UsdGeomXformCache();

    USDGEOM_API
    GfMatrix4d GetLocalToWorldTransform(const UsdPrim& prim);

    USDGEOM_API
    GfMatrix4d GetParentToWorldTransform(const UsdPrim& prim);

    USDGEOM_API
    GfMatrix4d GetLocalTransformation(const UsdPrim &prim,
                                      bool *resetsXformStack);

    USDGEOM_API
    GfMatrix4d ComputeRelativeTransform(const UsdPrim &prim,
                                        const UsdPrim &ancestor,
                                        bool *resetXformStack);

    USDGEOM_API
    bool IsAttributeIncludedInLocalTransform(const UsdPrim &prim, 
                                             const TfToken &attrName);

    USDGEOM_API
    bool TransformMightBeTimeVarying(const UsdPrim &prim);

    USDGEOM_API
    bool GetResetXformStack(const UsdPrim &prim);

    USDGEOM_API
    void Clear();

    USDGEOM_API
    void SetTime(UsdTimeCode time);

    UsdTimeCode GetTime() { return _time; }

    USDGEOM_API
    void Swap(UsdGeomXformCache& other);

private:

    // Traverses backwards the hierarchy starting from prim
    // all the way to the root and computes the ctm
    GfMatrix4d const* _GetCtm(const UsdPrim& prim);

    // Map of cached values.
    struct _Entry {
        _Entry() = default;
        _Entry(const UsdGeomXformable::XformQuery & query_,
               const GfMatrix4d& ctm_,
               bool ctmIsValid_)
            : query(query_)
            , ctm(ctm_)
            , ctmIsValid(ctmIsValid_)
        { }

        UsdGeomXformable::XformQuery query;
        GfMatrix4d ctm;
        bool ctmIsValid;
    };

    // Helper function to get or create a new entry for a prim in the ctm cache.
    _Entry * _GetCacheEntryForPrim(const UsdPrim &prim);

    typedef TfHashMap<UsdPrim, _Entry, TfHash> _PrimHashMap;
    _PrimHashMap _ctmCache;
    
    // The time at which this stack is querying and caching attribute values.
    UsdTimeCode _time;
};

#define USDGEOM_XFORM_CACHE_API_VERSION 1


PXR_NAMESPACE_CLOSE_SCOPE

#endif // PXR_USD_USD_GEOM_XFORM_CACHE_H