Constants:

GE_PATH_*_CHANNEL;

#define GE_PATH_ROTATION_CHANNEL    1
#define GE_PATH_TRANSLATION_CHANNEL 2
#define GE_PATH_ALL_CHANNELS (GE_PATH_ROTATION_CHANNEL | GE_PATH_TRANSLATION_CHANNEL)

gePath_Interpolator;

typedef enum{
    GE_PATH_INTERPOLATE_LINEAR  = 0, // linear blend for translation or rotation channel
    GE_PATH_INTERPOLATE_HERMITE,  // hermite cubic spline for translation channel
    GE_PATH_INTERPOLATE_SLERP,   // spherical-linear blend for rotation channel
    GE_PATH_INTERPOLATE_SQUAD,   // higher order blend for rotation channel 'G1' continuity
    //GE_PATH_INTEROPLATE_TRIPOD,   // not supported yet.
    GE_PATH_INTERPOLATE_HERMITE_ZERO_DERIV = 7 // hermite cubic with zero derivative at keyframes ('easing' curve)
}gePath_Interpolator;

Functions:

GENESISAPI gePath *GENESISCC gePath_Create(gePath_Interpolator TranslationInterpolation, gePath_Interpolator RotationInterpolation, geBoolean Looped);

This function creates a new gePath with the specified gePath_Interpolators for TranslationInterpolation and RotationInterpolation.  If Looped is GE_TRUE then the path is a looped path in which case the first and last points of the path should be identical.

Returns: the newly created gePath.

Notes:
    from PATH.H: creates new gePath. A looping path should have the same first & last point.  The path generator will choose arbitrarily between these points for a sample exactly at the end of the loop.

GENESISAPI gePath *GENESISCC gePath_CreateCopy(const gePath *P);

This function creates a new gePath as a copy of the specified gePath.

Returns: the newly created gePath.

GENESISAPI gePath* GENESISCC gePath_CreateFromFile(geVFile *F);

This function creates a new gePath from the specifed geVFile which may be either a binary or ascii path file.

Returns: the newly created gePath.

Notes:
    from PATH.H: loads a file  (binary or ascii)

GENESISAPI void GENESISCC gePath_CreateRef(gePath *P);

This function increases the reference count for the specifed gePath object by one.

Returns: nothing.

GENESISAPI void GENESISCC gePath_Destroy(gePath **PP);

This function decreases the reference count for the specified gePath by one.  If the reference count reaches zero then all resources for the gePath are released.

Return: nothing.

Notes:
    from PATH.H: destroys path *PP

GENESISAPI geBoolean GENESISCC gePath_DeleteKeyframe(gePath *P, int Index, int ChannelMask);

This function deletes the channels specifed by the ChannelMask from the Index indexed keyframe of gePath P.

Returns: GE_TRUE on success, GE_FALSE otherwise.

Notes:
    from PATH.H: deletes the nth keyframe

GENESISAPI void GENESISCC gePath_GetKeyframe(const gePath *P, int Index, int Channel, geFloat *Time, geXForm3d *Matrix);

This function returns a transformation matrix in Matrix for specified index Index and channel mask Channel of the gePath P.  The time for the specified index is also return in Time.

Returns: nothing.

Notes:
    from PATH.H: retrieves keyframe[index], and it's time

GENESISAPI int GENESISCC gePath_GetKeyframeCount(const gePath *P, int Channel);

This function returns the number of keyframes of type Channel defined in gePath P.

Returns: the result.

Notes:
    from PATH.H: retrieves count of keyframes for a specific channel

GENESISAPI int GENESISCC gePath_GetKeyframeIndex(const gePath *P, int Channel, geFloat Time);

This function returns the index for the keyframe of type Channel at time Time of gePath P.  If no keyframe exists for the specifed time and channel, -1 is returned.  Note that Channel must be either GE_PATH_ROTATION_CHANNEL or GE_PATH_TRANSLATION_CHANNEL.

Returns: the index, or -1 if specifed keyframe does not exist.

Notes:
    from PATH.H: retrieves the index of the keyframe at a specific time for a specific channel.

GENESISAPI geBoolean GENESISCC gePath_GetTimeExtents(const gePath *P, geFloat *StartTime, geFloat *EndTime);

This function gets the start and end times for the given gePath P.

Returns: GE_TRUE if keys are defined in P, GE_FALSE and no times if there are no keys defined in the path.

Notes:
    from PATH.H: gets the time for the first and last keys in the path (ignoring looping). if there are no keys, return GE_FALSE and times are not set. returns GE_TRUE if there are keys.

Questions:
    I said start and end time above, PATH.H says time of first and last frame; are these equivalent?  In other words, is there easing before the first frame or after the last frame or does the path simply end?

GENESISAPI geBoolean GENESISCC gePath_InsertKeyframe(gePath *P, int ChannelMask, geFloat Time, const geXForm3d *Matrix);

This function creates a new keyframe in path P at time T for the channel(s) specified Time as defined by the transform Matrix.

Returns: GE_TRUE on success, GE_FALSE otherwise.

Notes:
    from PATH.H: inserts a keyframe at a specific time.

GENESISAPI geBoolean GENESISCC gePath_ModifyKeyframe(gePath *P, int Index, int ChannelMask, const geXForm3d *Matrix);

This function updates the keyframe in path P at index Index for the specified channel(s) as defined by the transform Matrix.

Returns: GE_TRUE on success, GE_FALSE otherwise.

GENESISAPI geBoolean GENESISCC gePath_OffsetTimes(gePath *P, int StartingIndex, int ChannelMask, geFloat TimeOffset);

This function adjusts the time of all keyframes in path P of type ChannelMask starting with StartingIndex to the last frame by TimeOffset.

Returns: GE_TRUE on success, GE_FALSE otherwise.

Notes:
    from PATH.H: slides all samples in path starting with StartingIndex down by TimeOffset

Questions:
    Can TimeOffset be negative (in which case it would move the time up)?  What affect would it have to move a keyframes time so that it occurs earlier than the previous indexed frame?  Are keyframes assigned assumed to be sorted by time?

GENESISAPI void GENESISCC gePath_Sample(const gePath *P, geFloat Time, geXForm3d *Matrix);

This function returns the transformation Matrix for the path P at time Time.

Returns: nothing.

Notes:
    from PATH.H: returns a transform matrix sampled at 'Time'. p is not const because information is cached in p for next sample

void GENESISCC gePath_SampleChannels(const gePath *P, geFloat Time, geQuaternion *Rotation, geVec3d *Translation);

This function returns the Rotation and Translation for the path P at time Time.

Returns: nothing.

Notes:
    from PATH.H: returns a rotation and a translation for the path at 'Time' p is not const because information is cached in p for next sample

GENESISAPI geBoolean GENESISCC gePath_WriteToBinaryFile(const gePath *P, geVFile *F);

This function writes gePath P out to geVFile F in binary format.

Returns: GE_TRUE on success, GE_FALSE otherwise.

Notes:
    from PATH.H: dumps a minimal binary image for fastest reading

GENESISAPI geBoolean GENESISCC gePath_WriteToFile(const gePath *P, geVFile *F);

This function writes gePath P out to geVFile in ascii format.

Returns: GE_TRUE on success, GE_FALSE otherwise.

Notes:
    from PATH.H: dumps formatted ascii to the file.