//*****************************************************************************
//
//! Computes the angle between two quaternions
//!
//! \param pfQIn1 is a source quaternion in W,X,Y,Z form
//! \param pfQIn2 is a source quaternion in W,X,Y,Z form
//!
//! This function computes the angle between two quaternions.
//!
//! \return Returns the angle, in radians, between the two quaternions.
//
//*****************************************************************************
float
QuaternionAngle(float pfQIn1[4], float pfQIn2[4])
{
float pfQInv[4];
float pfQProd[4];
//
// Let Q1 and Q2 be two quaternions having components w,x,y,z. The angle
// between the orientations represented by Q1 and Q2 can be calculated
// with:
//
// angle = arccos( (Q2 * Q1').w ) * 2.0;
//
// where Q1' is the inverse of Q1
//
//
// Calculate the inverse of Q1
//
QuaternionInverse(pfQInv, pfQIn1);
//
// Find the product of Q2 x Q1`
//
QuaternionMult(pfQProd, pfQIn2, pfQInv);
//
// calculate the arccos of the w component of the previous product.
//
return(acosf(pfQProd[Q_W]) * 2.0);
}
void C_NPC_Hydra::StandardBlendingRules( Vector pos[], Quaternion q[], float currentTime, int boneMask )
{
VPROF( "C_NPC_Hydra::StandardBlendingRules" );
studiohdr_t *hdr = GetModelPtr();
if ( !hdr )
{
return;
}
int i;
// check for changing model memory requirements
bool bNewlyInited = false;
if (m_numHydraBones != hdr->numbones)
{
m_numHydraBones = hdr->numbones;
// build root animation
float poseparam[MAXSTUDIOPOSEPARAM];
for (i = 0; i < hdr->numposeparameters; i++)
{
poseparam[i] = 0;
}
CalcPose( hdr, NULL, pos, q, 0.0f, 0.0f, poseparam, BONE_USED_BY_ANYTHING );
// allocate arrays
if (m_boneLength)
{
delete[] m_boneLength;
}
m_boneLength = new float [m_numHydraBones];
if (m_vecPos)
{
delete[] m_vecPos;
}
m_vecPos = new Vector [m_numHydraBones];
if (m_iv_vecPos)
{
delete m_iv_vecPos;
}
m_iv_vecPos = new CInterpolatedVar< Vector >[m_numHydraBones];
for ( i = 0; i < m_numHydraBones; i++ )
{
m_iv_vecPos[ i ].Setup( &m_vecPos[ i ], LATCH_SIMULATION_VAR | EXCLUDE_AUTO_LATCH | EXCLUDE_AUTO_INTERPOLATE );
}
// calc models bone lengths
m_maxPossibleLength = 0;
for (i = 0; i < m_numHydraBones-1; i++)
{
m_boneLength[i] = (pos[i+1] - pos[i]).Length();
m_maxPossibleLength += m_boneLength[i];
}
m_boneLength[i] = 0.0f;
bNewlyInited = true;
}
// calc new bone setup if networked.
if (m_bNewChain)
{
CalcBoneChain( m_vecPos, m_vecChain );
for (i = 0; i < m_numHydraBones; i++)
{
// debugoverlay->AddLineOverlay( m_vecPos[i], m_vecPos[i<m_numHydraBones-1?i+1:m_numHydraBones-1], 0, 255, 0, false, 0.1 );
m_vecPos[i] = m_vecPos[i] - GetAbsOrigin();
m_iv_vecPos[i].NoteChanged( this, m_fLatchFlags, currentTime );
}
m_bNewChain = false;
}
// if just allocated, initialize bones
if (bNewlyInited)
{
for (i = 0; i < m_numHydraBones; i++)
{
m_iv_vecPos[i].Reset();
}
}
for (i = 0; i < m_numHydraBones; i++)
{
m_iv_vecPos[i].Interpolate( this, currentTime );
pos[ i ] = m_vecPos[ i ];
}
// calculate bone angles
CalcBoneAngles( pos, q );
// rotate the last bone of the hydra 90 degrees since it's oriented differently than the others
Quaternion qTmp;
AngleQuaternion( QAngle( 0, -90, 0) , qTmp );
QuaternionMult( q[m_numHydraBones - 1], qTmp, q[m_numHydraBones - 1] );
}
