//////////////////////////////////////////////////////////////////////////
// findDistanceByAttenuation
BcF32 ScnLightComponent::findDistanceByAttenuation( BcF32 Attenuation ) const
{
// If we want it at a low value, return max distance.
if( Attenuation < 0.05f )
{
Attenuation = 0.05f;
}
BcF32 A = AttnQ_;
BcF32 B = AttnL_;
BcF32 C = AttnC_ - ( 1.0f / Attenuation );
// 0 = Ax2 + Bx + C
if( A > 0.0f )
{
BcF32 Discriminant = ( ( B * B ) - ( 4.0f * A * C ) );
if( Discriminant < 0.0f )
{
return 1e24f;
}
return BcAbs( ( -B + BcSqrt( Discriminant ) ) / ( 2.0f * A ) );
}
// 0 = Bx + C
else if( B > 0.0f )
{
return BcAbs( -C / B );
}
// 0 = C
else
{
return 1e24f;
}
}
////////////////////////////////////////////////////////////////////////////////
// findPointOnEdge
BcBool MaBSPTree::lineIntersection( const MaVec3d& A, const MaVec3d& B, BcBSPPointInfo* pPointInfo, MaBSPNode* pNode /*= NULL*/ )
{
// Check if we want the root node.
if( pNode == NULL )
{
pNode = pRootNode_;
if( pPointInfo != NULL )
{
pPointInfo->Point_ = B;
pPointInfo->Distance_ = 1e12f;
}
}
// Really naive way...
BcBool Intersected = BcFalse;
// TODO: Handle coincident intersection!
MaPlane::eClassify ClassifyA = pNode->Plane_.classify( A, 0.0f );
MaPlane::eClassify ClassifyB = pNode->Plane_.classify( B, 0.0f );
if( ClassifyA == MaPlane::bcPC_FRONT && ClassifyB == MaPlane::bcPC_BACK )
{
BcF32 T;
MaVec3d Intersection;
if( pNode->Plane_.lineIntersection( A, B, T, Intersection ) )
{
// Is point in vertices? If so go down front to find nearer intersection.
if( pointOnNode( Intersection, pNode ) )
{
// If we want point info recurse deeper to get it.
if( pPointInfo != NULL )
{
BcF32 DistanceSquared = ( A - Intersection ).magnitudeSquared();
// Check the distance, if it's less then go deeper!
if( DistanceSquared < ( pPointInfo->Distance_ * pPointInfo->Distance_ ) )
{
pPointInfo->Plane_ = pNode->Plane_;
pPointInfo->Distance_ = BcSqrt( DistanceSquared );
pPointInfo->Point_ = Intersection;
}
}
Intersected |= BcTrue;
}
}
}
// NOTE: ClassifyB shouldn't be required here ...right?
if( pNode->pFront_ != NULL )
{
if( ClassifyA == MaPlane::bcPC_FRONT || ClassifyB == MaPlane::bcPC_FRONT )
{
Intersected |= lineIntersection( A, B, pPointInfo, pNode->pFront_ );
}
}
if( pNode->pBack_ != NULL )
{
if( ClassifyA == MaPlane::bcPC_BACK || ClassifyB == MaPlane::bcPC_BACK )
{
Intersected |= lineIntersection( A, B, pPointInfo, pNode->pBack_ );
}
}
return Intersected;
}
