ef2gamesource/dlls/game/CameraPath.cpp
Walter Julius Hennecke 5bbf27cabd Initial code commit ...
2012-12-30 17:37:54 +01:00

801 lines
27 KiB
C++

//-----------------------------------------------------------------------------
// CameraPath.cpp
//
// Author: Squirrel Eiserloh
//
// Copyright (C) 2002 by Ritual Entertainment, Inc.
// All rights reserved.
//
// This source is may not be distributed and/or modified without
// expressly written permission by Ritual Entertainment, Inc.
//
// DESCRIPTION:
// Implementation file for the following camera-related classes:
//
// CameraPath Describes a single camera path through time -
// including camera orientation, position,
// and field-of-view - using either many simple
// reference keyframes or a few bspline nodes.
// Also owns the coordinate system through which
// all positions and orientations are transformed
// (for scripts with relative playback locales).
//
// CameraKeyFramePath The innards of a CameraPath object implemented
// using keyframes (as opposed to bspline nodes).
// Does not know about relative locales.
//
// CameraKeyFrame A single key frame item in a CameraKeyFramePath.
// Stores a time index / frame number, the camera'a
// position (as a Vector), orientation (as a
// Quaternion), and field-of-fiew (as a Scalar).
//
#include "_pch_cpp.h"
#include "CameraPath.h"
/////////////////////////////////////////////////////////////////////////////////////////////////////////////
//
// CameraKeyFrame
//
/////////////////////////////////////////////////////////////////////////////////////////////////////////////
CLASS_DECLARATION( Class, CameraKeyFrame, NULL )
{
{ NULL, NULL }
};
//-----------------------------------------------------------------------------------------------
// Name: CameraKeyFrame
// Class: CameraKeyFrame
//
// Description: Default Constructor
//
// Parameters: None
//
// Returns: N/a
//
//-----------------------------------------------------------------------------------------------
CameraKeyFrame::CameraKeyFrame()
:
_position( Vector( 0.0f, 0.0f, 0.0f ) ),
_orientation( Quaternion( 0.0f, 0.0f, 0.0f, 1.0f ) ),
_fovDegrees( 90.0f ),
_seconds( 0.0f )
{
}
//-----------------------------------------------------------------------------------------------
// Name: CameraKeyFrame
// Class: CameraKeyFrame
//
// Description: Constructor( Vector, Quaternion, float )
//
// Parameters: position XYZ coordinates of camera
// orientation camera orientation as a quaternion
// fovDegrees horizontal fov of camera, in degrees
//
// Returns: n/a
//
//-----------------------------------------------------------------------------------------------
CameraKeyFrame::CameraKeyFrame( const Vector& position, const Quaternion& orientation, const float fovDegrees, const float seconds )
:
_position( position ),
_orientation( orientation ),
_fovDegrees( fovDegrees ),
_seconds( seconds )
{
}
//-----------------------------------------------------------------------------------------------
// Name: ParseFrameInfo
// Class: CameraKeyFrame
//
// Description: Starting with the keyword "Frame", parses one single frame entry from a .KFC
// buffer (using a Script object) in its entirety.
//
// Parameters: int frameNumber, Script& cameraPathFile
//
// Returns: bool - true upon success
//
//-----------------------------------------------------------------------------------------------
bool CameraKeyFrame::ParseFrameInfo( int frameNumber, Script& cameraPathFile, float& totalPathTime )
{
const char* token;
/// Read in the Frame number
token = cameraPathFile.GetToken( true );
if( !stricmp( token, "Frame" ) )
{
/// Make sure the frame number is the same as <frameNumber>, as expected
int actualFrame = cameraPathFile.GetInteger( false );
if( actualFrame != frameNumber )
{
cameraPathFile.error( "CameraKeyFrame::ParseFrameInfo", "Incorrect Frame number (found %d, expecting %d)\n", frameNumber, actualFrame );
return( false );
}
}
else // bad identifier
{
gi.Printf( "Unexpected token %s in camera path file (expecting \"Frame\").\n", token );
cameraPathFile.error( "CameraKeyFrame::ParseFrameInfo", "Unexpected token %s in camera path file (expecting \"Frame\").\n", token );
return( false );
}
return( ParseFrameInfoBlock( cameraPathFile, totalPathTime ) );
}
//-----------------------------------------------------------------------------------------------
// Name: ParseFrameInfoBlock
// Class: CameraKeyFrame
//
// Description: Parse in a single camera key frame from a .KFC file, from '{' to '}'
//
// Parameters: Script& cameraPathFile - parse object for .KFC file
//
// Returns: bool - true upon success
//
//-----------------------------------------------------------------------------------------------
bool CameraKeyFrame::ParseFrameInfoBlock( Script& cameraPathFile, float& totalPathTime )
{
const char* token;
float frameTimeInSeconds = DEFAULT_KEY_FRAME_LENGTH_SECONDS;
/// Read the opening bracket
token = cameraPathFile.GetToken( true );
if( *token != '{' )
{
cameraPathFile.error( "CameraKeyFrame::ParseFrameInfoBlock", "Expected '{', found \"%s\"\n", token );
return( false );
}
/// Read each entry in the Path info block
token = cameraPathFile.GetToken( true );
while( *token != '}' )
{
if( !stricmp( token, "fov" ) )
{
/// Read in the horizontal field of view (fov) for this camera key frame
_fovDegrees = cameraPathFile.GetFloat( false );
}
else if( !stricmp( token, "position" ) )
{
/// Read in the position vector for this camera key frame
_position = cameraPathFile.GetVector( false );
}
else if( !stricmp( token, "quaternion" ) )
{
/// Read in the orientation of the camera as a quaternion
float x = cameraPathFile.GetFloat( false );
float y = cameraPathFile.GetFloat( false );
float z = cameraPathFile.GetFloat( false );
float w = cameraPathFile.GetFloat( false );
_orientation.SetFromXYZW( x, y, z, w );
}
else // unknown token
{
gi.Printf( "Unexpected token %s in camera path file.\n", token );
cameraPathFile.error( "CameraKeyFrame::ParseFrameInfoBlock", "Unexpected token %s in camera path file.\n", token );
return( false );
}
token = cameraPathFile.GetToken( true );
}
_seconds = totalPathTime;
totalPathTime += frameTimeInSeconds;
return( true );
}
//-----------------------------------------------------------------------------------------------
// Name: Interpolate
// Class: CameraKeyFrame
//
// Description: Sets the position, orientation, and fov values in the current CameraKeyFrame
// object (this) to be a weighted average of two other key frames: <before> and
// <after>, where <fraction> represents the weighting of the <after> frame (and
// 1 - fraction is the weighting of the <before> frame).
//
// Parameters: const CameraKeyFrame& before - key frame being approached as fraction -> 0
// const CameraKeyFrame& after - key frame being approached as fraction -> 1
// const float fraction - in the range [0,1]; the fraction of <after> to be used
//
// Returns: const CameraKeyFrame&
//
//-----------------------------------------------------------------------------------------------
const CameraKeyFrame& CameraKeyFrame::Interpolate( const CameraKeyFrame& before, const CameraKeyFrame& after, const float fraction, const bool normalizeQuaternion )
{
/// Set up some convenience references
const Vector& pos1 = before.GetPosition();
const Vector& pos2 = after.GetPosition();
const Quaternion& quat1 = before.GetOrientation();
const Quaternion& quat2 = after.GetOrientation();
float fov1 = before.GetFOV();
float fov2 = after.GetFOV();
/// Calculate interpolated position, orientation, and fov values for this new frame
_position = pos1 + ( pos2 - pos1 ) * fraction; // linear componentwise interpolation
_orientation = CalcSlerp( quat1, quat2, (double) fraction ); // (hyper)spherical linear interpolation
_fovDegrees = fov1 + (fraction * (fov2 - fov1) ); // linear float interpolation
/// Check if the caller has requested the quaternion to be renormalized after interpolation (a good idea, but costly)
if( normalizeQuaternion )
_orientation.Normalize();
return( *this );
}
//-----------------------------------------------------------------------------------------------
// Name: GetEulerAngles
// Class: CameraKeyFrame
//
// Description: Returns the orientation of the key frame in Euler angles (pitch, yaw, roll).
// Note that orientations are internally stored as quaternions, and this function
// is mainly provided as a interface useful to the surrounding Euler-centric
// Quake / Fakk / Tiki code.
//
// Parameters:
//
// Returns: const Vector
//
//-----------------------------------------------------------------------------------------------
const Vector CameraKeyFrame::GetEulerAngles( void ) const
{
Vector eulerAngles;
_orientation.GetToEuler( eulerAngles );
return eulerAngles;
}
//-----------------------------------------------------------------------------------------------
// Name: TransformToPlaybackOffsets
// Class: CameraKeyFrame
//
// Description: Transforms a CameraKeyFrame object by (1) rotating it <yawOffsetDegrees> degrees
// (including orientations and positions) and then (2) translating it by
// <originOffset> world-units.
//
// Parameters: const float yawOffset - the amount of (yaw) rotation to apply
// const Vector& originOffset - the amount of translation to apply
//
// Returns: const CameraKeyFrame& - returns *this, now transformed
//
// NOTE: Because q_math.c is a C file and was written long ago, we use vec3_t and euler
// angles instead of Vector and Quaternion.
//-----------------------------------------------------------------------------------------------
const CameraKeyFrame& CameraKeyFrame::TransformToPlaybackOffsets( const float yawOffsetDegrees, const Vector& originOffset )
{
/// Rotate <_position> about the Z axis by <yawOffsetDegrees>
vec3_t zNormal = { 0.0f, 0.0f, 1.0f };
vec3_t point;
vec3_t rotated;
_position.copyTo( point ); // Don't blame me for this. Our math library was written in C.
RotatePointAroundVector( rotated, zNormal, point, yawOffsetDegrees );
_position = rotated;
/// Rotate <_orientation> in a like manner
Vector eulerOrientation;
_orientation.GetToEuler( eulerOrientation );
eulerOrientation.y += yawOffsetDegrees;
_orientation.SetFromEuler( eulerOrientation );
_orientation.Normalize();
/// Translate <_position> by <originOffset>
_position += originOffset; // see how easy things can be in C++?
return *this;
}
/////////////////////////////////////////////////////////////////////////////////////////////////////////////
//
// CameraKeyFramePath
//
/////////////////////////////////////////////////////////////////////////////////////////////////////////////
CLASS_DECLARATION( Class, CameraKeyFramePath, NULL )
{
{ NULL, NULL }
};
//-----------------------------------------------------------------------------------------------
// Name: CameraKeyFramePath
// Class: CameraKeyFramePath
//
// Description: Default Constructor
//
// Parameters: None
//
// Returns: n/a
//
//-----------------------------------------------------------------------------------------------
CameraKeyFramePath::CameraKeyFramePath()
:
_isLoaded( false ),
_numKeyFrames( 0 ),
_keyFrameArray( NULL ),
_totalSeconds( 0.0f )
{
}
//-----------------------------------------------------------------------------------------------
// Name: Unload
// Class: CameraKeyFramePath
//
// Description: Destroys the key-framed camera path data and
// marks the object as dirty (_isLoaded = false).
//
// Parameters: void
//
// Returns: void
//
//-----------------------------------------------------------------------------------------------
void CameraKeyFramePath::Unload( void )
{
if( IsLoaded() )
{
delete [] _keyFrameArray;
_keyFrameArray = NULL;
}
_totalSeconds = 0.0f;
_isLoaded = false;
}
//-----------------------------------------------------------------------------------------------
// Name: CreateFrames
// Class: CameraKeyFramePath
//
// Description: Allocates <numberOfFrames> CameraKeyFrame objects
// in a dynamic array. Previous data, if any, is
// deleted.
//
// Parameters: numberOfFrames - The number of key frames to be allocated.
//
// Returns: bool - true upon success
//
//-----------------------------------------------------------------------------------------------
bool CameraKeyFramePath::CreateFrames( const int numberOfFrames )
{
/// Unload the previous data (if any)
Unload();
/// Allocte <numberOFFrames> CameraKeyFrame objects
_keyFrameArray = new CameraKeyFrame[ numberOfFrames ];
if( !_keyFrameArray )
return( false );
/// Set internal dependents
_numKeyFrames = numberOfFrames;
return( true );
}
//-----------------------------------------------------------------------------------------------
// Name: ParsePathInfo
// Class: CameraKeyFramePath
//
// Description: Parses a "Path" entry and all subsequent "Frame" entries for that path.
// Parsing begins at the '{' following the "Path" keyword (already parsed).
//
// Parameters: Script& cameraPathFile - parsing object; keeps track of parse-offset, etc.
//
// Returns: bool - true upon success
//
//-----------------------------------------------------------------------------------------------
bool CameraKeyFramePath::ParsePathInfo( Script& cameraPathFile )
{
const char* token;
/// Read the opening bracket
token = cameraPathFile.GetToken( true );
if( *token != '{' )
{
cameraPathFile.error( "CameraKeyFramePath::ParsePathInfo", "Expected '{', found \"%s\"\n", token );
return( false );
}
/// Read each entry in the Path info block
token = cameraPathFile.GetToken( true );
while( *token != '}' )
{
if( !stricmp( token, "frameCount" ) )
{
/// Read in the number of frames in the path
_numKeyFrames = cameraPathFile.GetInteger( false );
assert( _numKeyFrames > 0 );
}
else // unknown token
{
gi.Printf( "Unexpected token %s in camera path file.\n", token );
cameraPathFile.error( "CameraKeyFramePath::ParsePathInfo", "Unexpected token %s in camera path file.\n", token );
return( false );
}
token = cameraPathFile.GetToken( true );
}
/// Allocate an array of CameraKeyFrame objects equal in number to what "frameCount" specified
CreateFrames( _numKeyFrames );
/// Loop through each key frame and let it parse itself
for( int i = 0; i < _numKeyFrames; i ++ )
{
/// Tell each frame to parse itself
CameraKeyFrame& keyFrame = _keyFrameArray[ i ];
bool success = keyFrame.ParseFrameInfo( i, cameraPathFile, _totalSeconds );
if( !success )
return( false );
}
/// Inform the object that it has been successfully loaded and is ready for use
_isLoaded = true;
return( true );
}
//-----------------------------------------------------------------------------------------------
// Name: GetClosestFramesForTime
// Class: CameraKeyFramePath
//
// Description: Sets <before> and <after> pointers to the camera key frames closest in time
// to <seconds>. Both pointers are guaranteed to always be set, though they
// may be identical (especially in cases where <seconds> matches a frame exactly,
// or where <seconds> is out of the time bounds of the path).
//
// Parameters: CameraKeyFrame*& before - pointer (by reference) to be set to the closest
// frame at or before <seconds>
//
// CameraKeyFrame*& after - pointer (by reference) to be set to the closest
// frame at or after <seconds>
//
// const float seconds - the time offset, in seconds, from the beginning of the
// camera path, around which the search for closest frames is centered
//
// Returns: void
//
//-----------------------------------------------------------------------------------------------
void CameraKeyFramePath::GetClosestFramesForTime( CameraKeyFrame*& before, CameraKeyFrame*& after, const float seconds )
{
int i;
/// Find the frame closest to - but no greater than - <seconds>
before = &_keyFrameArray[ 0 ];
for( i = 0; i < _numKeyFrames; i ++ )
{
CameraKeyFrame& frame = _keyFrameArray[ i ];
if( frame.GetSeconds() > seconds )
break;
before = &frame;
}
/// Find the frame closest to - but no less than - <seconds>
after = &_keyFrameArray[ _numKeyFrames - 1 ];
for( i = _numKeyFrames - 1; i >= 0; i -- )
{
CameraKeyFrame& frame = _keyFrameArray[ i ];
if( frame.GetSeconds() < seconds )
break;
after = &frame;
}
}
//-----------------------------------------------------------------------------------------------
// Name: CreateInterpolatedFrameForTime
// Class: CameraKeyFramePath
//
// Description: Creates a new CameraKeyFrame object based on the best interpolated-approximation
// of the CameraKeyFramePath when evaluated at <seconds> time.
//
// Parameters: const float seconds - time at which to evaluate the camera path
//
// Returns: const CameraKeyFrame - a new key frame, created by interpolating (if necessary)
// between the key frames in the camera path closest to <seconds>.
//
//-----------------------------------------------------------------------------------------------
const CameraKeyFrame CameraKeyFramePath::CreateInterpolatedFrameForTime( const float seconds )
{
/// Check if <seconds> is out-of-bounds for this camera path
if( seconds < 0.0f )
{
/// Return a copy of the first key frame
return( _keyFrameArray[ 0 ] );
}
else if( seconds > _totalSeconds )
{
/// Return a copy of the last key frame
return( _keyFrameArray[ _numKeyFrames - 1 ] );
}
/// Get the two closest frames in time to <seconds>; one just before and one just after
CameraKeyFrame* closestFrameBefore = NULL;
CameraKeyFrame* closestFrameAfter = NULL;
GetClosestFramesForTime( closestFrameBefore, closestFrameAfter, seconds );
assert( closestFrameBefore );
assert( closestFrameAfter );
/// Check if both frames are identical; if so, simply return a copy of it / them
if( closestFrameBefore == closestFrameAfter )
return( *closestFrameBefore );
/// Generate an interpolated frame based on where <seconds> falls between those two frames
return( CreateInterpolatedFrame( *closestFrameBefore, *closestFrameAfter, seconds ) );
}
//-----------------------------------------------------------------------------------------------
// Name: CreateInterpolatedFrame
// Class: CameraKeyFramePath
//
// Description: Creates a new CameraKeyFrame object based on the best interpolated-approximation
// of the CameraKeyFramePath when evaluated at <seconds> time. NOTE: This method
// is called by CreateInterpolatedFrameForTime(), above, and does all the real
// interpolation work.
//
// Parameters: const CameraKeyFrame& before - closest frame shy of <seconds>
// const CameraKeyFrame& after - closest frame past <seconds>
// const float seconds - time index used to interpolate between <before> and <after>
//
// Returns: const CameraKeyFrame - new, interpolated key frame
//
//-----------------------------------------------------------------------------------------------
const CameraKeyFrame CameraKeyFramePath::CreateInterpolatedFrame( const CameraKeyFrame& before, const CameraKeyFrame& after, const float seconds )
{
/// Calculate the amount of time between the two reference frames
const float startTime = before.GetSeconds();
const float endTime = after.GetSeconds();
const float timeSpan = endTime - startTime;
assert( timeSpan >= 0.0f );
assert( seconds >= startTime );
assert( seconds <= endTime );
/// Calculation the interpolation fraction
float fraction;
if( timeSpan )
{
fraction = (seconds - startTime) / timeSpan;
}
else
{
fraction = 0.0f;
}
/// Create a new frame with interpolated values
CameraKeyFrame lerped;
lerped.Interpolate( before, after, fraction, true );
return( lerped );
}
//-----------------------------------------------------------------------------------------------
// Name: GetPathLengthInSeconds
// Class: CameraKeyFramePath
//
// Description: Returns the total length of the camera path, in seconds.
//
// Parameters: void
//
// Returns: float - the total length of the camera path, in seconds.
//
//-----------------------------------------------------------------------------------------------
float CameraKeyFramePath::GetPathLengthInSeconds( void )
{
return( _totalSeconds );
}
/////////////////////////////////////////////////////////////////////////////////////////////////////////////
//
// CameraPath
//
/////////////////////////////////////////////////////////////////////////////////////////////////////////////
CLASS_DECLARATION( Class, CameraPath, NULL )
{
{ NULL, NULL }
};
//-----------------------------------------------------------------------------------------------
// Name: CameraPath
// Class: CameraPath
//
// Description: Construct from .KFC file
//
// Parameters: fileName Name of the .KFC file to parse on construction of this object.
//
// Returns: n/a
//
//-----------------------------------------------------------------------------------------------
CameraPath::CameraPath( const str& fileName )
:
_fileName( str( "" ) ),
_isLoaded( false ),
_keyFramePath( NULL ),
_yawPlaybackOffsetDegrees( 0.0f ),
_originPlaybackOffset( Vector( 0.0f, 0.0f, 0.0f ) )
{
LoadKeyFramedCameraFile( fileName );
}
//-----------------------------------------------------------------------------------------------
// Name: LoadKeyFramedCameraFile
// Class: CameraPath
//
// Description: Loads a .KFC file and builds a dynamic array of camera key frames.
// Any previously loaded data in this object is destroyed.
//
// Parameters: fileName - Name of the .KFC file to load and parse.
//
// Returns: bool - true upon success
//
//-----------------------------------------------------------------------------------------------
bool CameraPath::LoadKeyFramedCameraFile( const str& fileName )
{
Script cameraPathFile;
const char* token;
bool success; // generic parsing return-value variable
str filePathName;
/// Unload the previous data (if any)
Unload();
/// Store the filename in the object for duplicate-load later on
_fileName = fileName;
/// Build the new file path name
filePathName = "cams/";
filePathName += fileName;
filePathName += ".kfc";
/// Load the file into a buffer (in the Script object)
cameraPathFile.LoadFile( filePathName.c_str() );
/// Parse each token in turn until no more remain
while( cameraPathFile.TokenAvailable( true ) )
{
/// Read the next token-word and take the appropriate action
token = cameraPathFile.GetToken( true );
if( !stricmp( token, "Path" ) )
{
/// Read in the path info and its subsequent key frame data
success = ParsePathInfo( cameraPathFile );
if( !success )
return( false );
}
else // unknown token
{
gi.Printf( "Unexpected token %s in camera path file %s.\n", token, _fileName.c_str() );
cameraPathFile.error( "CameraPath::LoadKeyFramedCameraFile", "Unexpected token %s in camera path file %s.\n", token, _fileName.c_str() );
return( false );
}
}
/// Inform the object that it has been successfully loaded and is ready for use
_isLoaded = true;
return( true );
}
//-----------------------------------------------------------------------------------------------
// Name: Unload
// Class: CameraPath
//
// Description: Destroys the camera path data and marks the object as dirty (_isLoaded = false).
//
// Parameters: void
//
// Returns: void
//
//-----------------------------------------------------------------------------------------------
void CameraPath::Unload( void )
{
if( IsLoaded() )
{
_isLoaded = false;
delete _keyFramePath;
_keyFramePath = NULL;
}
}
//-----------------------------------------------------------------------------------------------
// Name: ParsePathInfo
// Class: CameraPath
//
// Description: Parses the Path #, allocates a new path object, and passes parsing duties onto it.
//
// Parameters: Script& cameraPathFile - parsing object
//
// Returns: bool - true upon success
//
//-----------------------------------------------------------------------------------------------
bool CameraPath::ParsePathInfo( Script& cameraPathFile )
{
/// Read the path number
int pathNumber = cameraPathFile.GetInteger( false );
assert( pathNumber == 0 ); // FIXME: this is only temporary, until we allow more than one path per .kfc
/// Create a new key frame camera path and pass parsing duties on to it
_keyFramePath = new CameraKeyFramePath;
bool success = _keyFramePath->ParsePathInfo( cameraPathFile );
return( success );
}
//-----------------------------------------------------------------------------------------------
// Name: GetInterpolatedFrameForTime
// Class: CameraPath
//
// Description: Returns a newly created temporary object; the resulting camera key frame when
// the CameraPath is evaluated at <seconds>.
//
// Parameters: const float seconds - time index at which to evaluate the camera path
//
// Returns: const CameraKeyFrame - key frame created as a result of interpolation / evaluation
//
//-----------------------------------------------------------------------------------------------
const CameraKeyFrame CameraPath::GetInterpolatedFrameForTime( const float seconds )
{
CameraKeyFrame transformedKeyFrame( _keyFramePath->CreateInterpolatedFrameForTime( seconds ) );
transformedKeyFrame.TransformToPlaybackOffsets( _yawPlaybackOffsetDegrees, _originPlaybackOffset );
return( transformedKeyFrame );
}
//-----------------------------------------------------------------------------------------------
// Name: SetPlaybackOffsets
// Class: CameraPath
//
// Description: Tells a CameraPath object what offsets to use when reporting interpolations /
// evaluations. <yawOffset> is applied first to all positions and orientations;
// <originOffset> is applied last (to positions only).
//
// Parameters: const float yawOffsetDegrees - yaw rotation to apply to all positions & orientations
// const Vector& originOffset - offset translation applied to all positions, post-rotation
//
// Returns: void
//
//-----------------------------------------------------------------------------------------------
void CameraPath::SetPlaybackOffsets( const float yawOffsetDegrees, const Vector& originOffset )
{
_yawPlaybackOffsetDegrees = yawOffsetDegrees;
_originPlaybackOffset = originOffset;
}
//-----------------------------------------------------------------------------------------------
// Name: GetPathLengthInSeconds
// Class: CameraPath
//
// Description: Returns the total length of the camera path, in seconds.
//
// Parameters: void
//
// Returns: float - the total length of the camera path, in seconds
//
//-----------------------------------------------------------------------------------------------
float CameraPath::GetPathLengthInSeconds( void )
{
return( _keyFramePath->GetPathLengthInSeconds() );
}