/**
* @param vRayStart Start point of an infinite ray.
* @param vRayOffset Direction of the ray, parametric t multiplier.
* @param fT0 Filled in with time of first intersection (if present).
* @param fT1 Filled in with time of second intersection (if present).
* @return The number of intersections found.
*/
UINT32 CCircle::GetLineIntersectionTimes(CFVec2Arg vRayStart, CFVec2Arg vRayOffset, GDE::FLOAT32 &fT0, GDE::FLOAT32 &fT1) const
{
const CFVec2 vToRay = vRayStart - m_vCentre;
// TODO: reformulate without the square root?
const FLOAT32 fExtentsRecip = 1.0f/vRayOffset.Magnitude();
const FLOAT32 fRayDotToRay = vToRay.DotProduct( vRayOffset ) * fExtentsRecip;
const FLOAT32 fDiscr = fRayDotToRay*fRayDotToRay - (vToRay.SquareMagnitude()-m_fRadius*m_fRadius);
if ( fDiscr < 0.0f )
{
return 0; // no intersections.
}
if ( fDiscr == 0.0f )
{
fT0 = -fRayDotToRay * fExtentsRecip;
return 1; // one intersection, just touching
} else
{
const FLOAT32 fRoot = sqrtf( fDiscr );
fT0 = (-fRayDotToRay - fRoot) * fExtentsRecip;
fT1 = (-fRayDotToRay + fRoot) * fExtentsRecip;
return 2; // two intersections.
}
}
void CSquirrel::Update( FLOAT32 fTimeDelta )
{
if ( 0 == m_uNumLives )
{
return;
}
const static CFVec2 s_vMoveOffsets[] =
{
SFVec2( -1.0f, 0.0f ), //"Left",
SFVec2( 1.0f, 0.0f ), //"Right",
SFVec2( 0.0f, -1.0f ), //"Up",
SFVec2( 0.0f, 1.0f ), //"Down"
};
_COMPILE_ASSERT( _ARRAY_SIZE( s_vMoveOffsets ) == EMove_COUNT );
CFVec2 vMove = SFVec2( 0.0f, 0.0f );
for ( UINT32 i=0; i< EMove_COUNT; i++ )
{
if ( m_Movements[i].m_bValue )
{
vMove += s_vMoveOffsets[i];
}
}
// great, now we have the movement direction.
if ( vMove.SquareMagnitude() != 0.0f )
{
m_fDistTimeMoving += fTimeDelta;
vMove.Normalise();
FLOAT32 fStep = 1.0f;
CFVec2 vTestedMove = vMove * fTimeDelta * m_fSpeed * fStep;
// now check the target position - is it embedded in any walls?
CCircle TargetBounds;
while ( fStep > 0.0f )
{
TargetBounds.Initialise( m_vPosition + vTestedMove, m_fRadius );
if ( false == CMMMContext::GetInstance().CircleIntersectsGeometry( TargetBounds ) )
{
break; // found a valid, allowable movement.
}
fStep -= 0.2f;
vTestedMove = vMove * fTimeDelta * m_fSpeed * fStep;
}
// now update to the new position
m_vPosition += vTestedMove;
// finally what happens at the new position
// is an acorn collected?
if ( m_uNumAcorns != m_uMaxAcorns )
{
CAcorn* pLevelAcorns;
UINT32 uNumLevelAcorns;
CMMMContext::GetInstance().GetAcorns( pLevelAcorns, uNumLevelAcorns );
for ( UINT32 i=0; i<uNumLevelAcorns; i++ )
{
if ( pLevelAcorns[i].GetState() == CAcorn::ES_Available )
{
if ( pLevelAcorns[i].Intersects( TargetBounds ) )
{
pLevelAcorns[i].SetState( CAcorn::ES_Carried );
m_ppAcorns[m_uNumAcorns++] = pLevelAcorns+i;
if ( m_uNumAcorns == m_uMaxAcorns )
{
break; // cannont collect any more!
}
}
}
}
}
// is a tunnel reached?
if ( m_uNumAcorns > 0 )
{
CTunnel* pTunnels;
UINT32 uNumTunnels;
CMMMContext::GetInstance().GetTunnels( pTunnels, uNumTunnels );
for ( UINT32 i=0; i<uNumTunnels; i++ )
{
if ( pTunnels[i].Intersects( TargetBounds ) )
{
// reached the tunnel.
for ( UINT32 i=0; i<m_uNumAcorns; i++ )
{
m_ppAcorns[i]->SetState( CAcorn::ES_Collected );
m_uScore++;
}
m_uNumAcorns = 0;
}
}
}
}
m_fTimeToDisturbance -= fTimeDelta;
if ( m_fTimeToDisturbance <= 0.0f )
{
// schedule the next disturbance.
m_fTimeToDisturbance = FLOAT32(rand())/FLOAT32(RAND_MAX);
m_fTimeToDisturbance *= m_fMaxDistSep-m_fMinDistSep;
m_fTimeToDisturbance += m_fMinDistSep;
// create this disturbance:
FLOAT32 fRad = m_fLastDistDelay=0.0f?0.0f:m_fDistTimeMoving/m_fLastDistDelay;
// DbgPrint( "Creating Disturbance strength %0.2f, next delay %0.2f\n", fRad,m_fTimeToDisturbance );
fRad *= m_fMaxDistRad-m_fMinDistRad;
fRad += m_fMinDistRad;
if ( fRad >= 0.0f )
{
CCircle Dist;
Dist.Initialise( m_vPosition, fRad );
CMMMContext::GetInstance().CreateDisturbance( Dist );
}
m_fDistTimeMoving = 0.0f;
m_fLastDistDelay = m_fTimeToDisturbance;
}
}