knot.h

//
// Copyright 2024 Pixar
//
// Licensed under the terms set forth in the LICENSE.txt file available at
// https://openusd.org/license.
//
 
#ifndef PXR_BASE_TS_KNOT_H
#define PXR_BASE_TS_KNOT_H
 
#include "pxr/pxr.h"
#include "pxr/base/ts/api.h"
#include "pxr/base/ts/knotData.h"
#include "pxr/base/ts/types.h"
#include "pxr/base/ts/typeHelpers.h"
#include "pxr/base/vt/dictionary.h"
#include "pxr/base/vt/value.h"
#include "pxr/base/gf/half.h"
#include "pxr/base/gf/timeCode.h"
#include "pxr/base/tf/diagnostic.h"
#include "pxr/base/tf/preprocessorUtilsLite.h"
#include "pxr/base/tf/type.h"
 
#include <iosfwd>
#include <memory>
#include <optional>
#include <string>
#include <type_traits>
 
PXR_NAMESPACE_OPEN_SCOPE
 
 
class TsKnot
{
public:
 
    TS_API
    TsKnot();
 
    TS_API
    TsKnot(
        TfType valueType);
 
    TS_API
    TsKnot(
        TfType valueType,
        TsCurveType curveType);
 
    TS_API
    TsKnot(const TsKnot &other);
 
    TS_API
    TsKnot(TsKnot &&other);
 
    TS_API
    ~TsKnot();
 
    TS_API
    TsKnot& operator=(const TsKnot &other);
 
    TS_API
    TsKnot& operator=(TsKnot &&other);
 
    TS_API
    bool operator==(const TsKnot &other) const;
 
    TS_API
    bool operator!=(const TsKnot &other) const;
 
 
    TS_API
    bool SetTime(
        TsTime time);
 
    TS_API
    TsTime GetTime() const;
 
 
    TS_API
    bool SetNextInterpolation(TsInterpMode mode);
 
    TS_API
    TsInterpMode GetNextInterpolation() const;
 
 
    TS_API
    TfType GetValueType() const;
 
    template <typename T>
    bool IsHolding() const;
 
    TS_API
    bool SetValue(
        VtValue value);
 
    template <typename T>
    bool SetValue(
        const T value);
 
    TS_API
    bool GetValue(
        VtValue *valueOut) const;
 
    template <typename T>
    bool GetValue(
        T *valueOut) const;
 
 
    TS_API
    bool IsDualValued() const;
 
    TS_API
    bool SetPreValue(
        VtValue value);
 
    template <typename T>
    bool SetPreValue(
        const T value);
 
    TS_API
    bool GetPreValue(
        VtValue *valueOut) const;
 
    template <typename T>
    bool GetPreValue(
        T *valueOut) const;
 
    TS_API
    bool ClearPreValue();
 
 
    TS_API
    bool SetCurveType(TsCurveType curveType);
 
    TS_API
    TsCurveType GetCurveType() const;
 
 
    TS_API
    bool SetPreTanWidth(TsTime width);
 
    TS_API
    TsTime GetPreTanWidth() const;
 
    TS_API
    bool SetPreTanSlope(VtValue slope);
 
    template <typename T>
    bool SetPreTanSlope(T slope);
 
    TS_API
    bool GetPreTanSlope(VtValue *slopeOut) const;
 
    template <typename T>
    bool GetPreTanSlope(T *slopeOut) const;
 
    TS_API
    bool SetPreTanAlgorithm(TsTangentAlgorithm algorithm);
 
    TS_API
    TsTangentAlgorithm GetPreTanAlgorithm() const;
 
 
    TS_API
    bool SetPostTanWidth(TsTime width);
 
    TS_API
    TsTime GetPostTanWidth() const;
 
    TS_API
    bool SetPostTanSlope(VtValue slope);
 
    template <typename T>
    bool SetPostTanSlope(T slope);
 
    TS_API
    bool GetPostTanSlope(VtValue *slopeOut) const;
 
    template <typename T>
    bool GetPostTanSlope(T *slopeOut) const;
 
    TS_API
    bool SetPostTanAlgorithm(TsTangentAlgorithm algorithm);
 
    TS_API
    TsTangentAlgorithm GetPostTanAlgorithm() const;
 
 
    TS_API
    bool UpdateTangents(const std::optional<TsKnot> prevKnot,
                        const std::optional<TsKnot> nextKnot,
                        TsCurveType curveType = TsCurveTypeBezier);
 
 
    TS_API
    bool SetCustomData(
        VtDictionary customData);
 
    TS_API
    VtDictionary GetCustomData() const;
 
    TS_API
    bool SetCustomDataByKey(
        const std::string &keyPath,
        VtValue value);
 
    TS_API
    VtValue GetCustomDataByKey(
        const std::string &keyPath) const;
 
 
    TS_API
    bool IsC0Continuous() const;
 
    TS_API
    bool IsG1Continuous() const;
 
    TS_API
    bool IsC1Continuous() const;
 
 
protected:
    friend class TsSpline;
    friend class TsKnotMap;
    friend class TsRegressionPreventer;
 
    // Constructor for copying knot data from SplineData.  The data has been
    // copied for us, and we take ownership of it.
    TsKnot(
        Ts_KnotData *data,
        TfType valueType,
        VtDictionary &&customData);
 
    // Accessors for low-level knot data.
    Ts_KnotData* _GetData() { return _data; }
    const Ts_KnotData* _GetData() const { return _data; }
 
private:
    template <typename T>
    bool _CheckInParam(T value) const;
 
    template <typename T>
    bool _CheckOutParam(T *valueOut) const;
 
    bool _CheckSetWidth(TsTime width) const;
    bool _CheckInParamVt(VtValue value) const;
    bool _CheckOutParamVt(VtValue* value) const;
 
    // Helpers to transform external VtValues holding time codes to and from
    // internally stored VtValues holding doubles. If TsKnot::GetValueType
    // isn't a time code, these functions return the stored value as-is.
    VtValue _ToStorage(const VtValue& value) const;
    VtValue _FromStorage(const VtValue& value) const;
 
    template <typename T>
    Ts_TypedKnotData<Ts_StorageType<T>>* _TypedData() const;
 
    template <typename T>
    const Ts_TypedKnotData<Ts_StorageType<T>>* _ConstTypedData() const;
 
private:
    // Main knot fields.  Never null.  The data is on the heap, and we own it
    // exclusively, but we don't use unique_ptr because we need to deallocate in
    // a type-aware way; see the destructor.
    Ts_KnotData* _data;
 
    // Proxy object, for typed data access.  Never null.
    //
    // XXX: it would be possible to eliminate this member by encoding value type
    // in a bitfield in Ts_KnotData; there are only three possible value types,
    // and there are plenty of unused bits in the Ts_KnotData padding.  Then we
    // could create proxy objects on the fly, or make them singletons.
    //
    std::unique_ptr<Ts_KnotDataProxy> _proxy;
 
    // Custom data.  Optional; may be empty.
    VtDictionary _customData;
};
 
TS_API
std::ostream& operator<<(std::ostream& out, const TsKnot &knot);
 
 
template <typename T,
          typename = std::enable_if_t<Ts_IsSupportedValueType<T>::value>>
class TsTypedKnot : public TsKnot
{
public:
    TsTypedKnot() : TsKnot(Ts_GetType<T>()) {}
};
 
using TsDoubleKnot = TsTypedKnot<double>;
 
using TsFloatKnot = TsTypedKnot<float>;
 
using TsHalfKnot = TsTypedKnot<GfHalf>;
 
using TsTimeCodeKnot = TsTypedKnot<GfTimeCode>;
 
// Make sure we have coverage for all allowed types.
#define _MAKE_CLAUSE(unused, tuple)                                          \
    static_assert(std::is_same_v<TF_PP_CAT(TF_PP_CAT(Ts,                     \
                    TS_SPLINE_VALUE_TYPE_NAME(tuple)), Knot),                \
                  TsTypedKnot<TS_SPLINE_VALUE_CPP_TYPE(tuple)>>,             \
                  "Incorrect type alias for TsKnot type: " #tuple);
TF_PP_SEQ_FOR_EACH(_MAKE_CLAUSE, ~, TS_SPLINE_SUPPORTED_VALUE_TYPES)
#undef _MAKE_CLAUSE
 
 
 
// TEMPLATE HELPERS
 
template <typename T>
bool TsKnot::_CheckInParam(const T value) const
{
    if constexpr (!Ts_IsSupportedValueType<T>::value)
    {
        static_assert(Ts_IsSupportedValueType<T>::value,
            "Cannot pass unsupported type as T-typed knot parameter");
        return false;
    }
    else
    {
        if (GetValueType() != Ts_GetType<T>())
        {
            TF_CODING_ERROR(
                "Cannot set '%s' value into knot of type '%s'",
                Ts_GetType<T>().GetTypeName().c_str(),
                GetValueType().GetTypeName().c_str());
            return false;
        }
 
        if (!Ts_IsFinite(value))
        {
            TF_CODING_ERROR("Set values must be finite.");
            return false;
        }
 
        return true;
    }
}
 
template <typename T>
bool TsKnot::_CheckOutParam(T *valueOut) const
{
    if constexpr (!Ts_IsSupportedValueType<T>::value)
    {
        static_assert(Ts_IsSupportedValueType<T>::value,
            "Cannot pass non-floating-point type as T-typed knot parameter");
        return false;
    }
    else
    {
        if (!valueOut)
        {
            TF_CODING_ERROR("Null pointer");
            return false;
        }
 
        if (GetValueType() != Ts_GetType<T>())
        {
            TF_CODING_ERROR(
                "Cannot read from knot of type '%s' into '%s'",
                GetValueType().GetTypeName().c_str(),
                Ts_GetType<T>().GetTypeName().c_str());
            return false;
        }
 
        return true;
    }
}
 
template <typename T>
Ts_TypedKnotData<Ts_StorageType<T>>*
TsKnot::_TypedData() const
{
    return static_cast<Ts_TypedKnotData<Ts_StorageType<T>>*>(_data);
}
 
template <typename T>
const Ts_TypedKnotData<Ts_StorageType<T>>*
TsKnot::_ConstTypedData() const
{
    return static_cast<const Ts_TypedKnotData<Ts_StorageType<T>>*>(_data);
}
 
// TEMPLATE IMPLEMENTATIONS
 
template <typename T>
bool TsKnot::IsHolding() const
{
    return GetValueType() == Ts_GetType<T>();
}
 
template <typename T>
bool TsKnot::SetValue(const T value)
{
    if (!_CheckInParam(value))
    {
        return false;
    }
 
    _TypedData<T>()->value = Ts_StorageType<T>(value);
    return true;
}
 
template <typename T>
bool TsKnot::GetValue(T *valueOut) const
{
    if (!_CheckOutParam(valueOut))
    {
        return false;
    }
 
    *valueOut = _ConstTypedData<T>()->value;
    return true;
}
 
template <typename T>
bool TsKnot::SetPreValue(const T value)
{
    if (!_CheckInParam(value))
    {
        return false;
    }
 
    _data->dualValued = true;
    _TypedData<T>()->preValue = Ts_StorageType<T>(value);
    return true;
}
 
template <typename T>
bool TsKnot::GetPreValue(T* const valueOut) const
{
    if (!_CheckOutParam(valueOut))
    {
        return false;
    }
 
    if (_data->dualValued)
    {
        *valueOut = _ConstTypedData<T>()->preValue;
    }
    else
    {
        *valueOut = _ConstTypedData<T>()->value;
    }
 
    return true;
}
 
// Pre-Tangent
 
template <typename T>
bool TsKnot::SetPreTanSlope(const T slope)
{
    if (!_CheckInParam(slope))
    {
        return false;
    }
 
    _TypedData<T>()->preTanSlope = Ts_StorageType<T>(slope);
    return true;
}
 
template <typename T>
bool TsKnot::GetPreTanSlope(T* const slopeOut) const
{
    if (!_CheckOutParam(slopeOut))
    {
        return false;
    }
 
    *slopeOut = _ConstTypedData<T>()->GetPreTanSlope();
    return true;
}
 
// Post-Tangent
 
template <typename T>
bool TsKnot::SetPostTanSlope(const T slope)
{
    if (!_CheckInParam(slope))
    {
        return false;
    }
 
    _TypedData<T>()->postTanSlope = Ts_StorageType<T>(slope);
    return true;
}
 
template <typename T>
bool TsKnot::GetPostTanSlope(T* const slopeOut) const
{
    if (!_CheckOutParam(slopeOut))
    {
        return false;
    }
 
    *slopeOut = _ConstTypedData<T>()->GetPostTanSlope();
    return true;
}
 
 
PXR_NAMESPACE_CLOSE_SCOPE
 
#endif