/*-------------------------------------------------------------------
Procedure : Create Quat from dir vector and up vector
Input : VECTOR * Direction Vector
: VECTOR * Up Vector
: QUAT * Destin Quaternion
Output : Nothing
-------------------------------------------------------------------*/
void QuatFromDirAndUp( VECTOR * Dir, VECTOR * Up, QUAT * Quat )
{
MATRIX TempMat;
VECTOR TempUp;
QUAT RotQuat;
QuatFrom2Vectors( Quat, &Forward, Dir );
QuatToMatrix( Quat, &TempMat );
ApplyMatrix( &TempMat, &SlideUp, &TempUp );
QuatFrom2Vectors( &RotQuat, &TempUp, Up );
QuatMultiply( &RotQuat, Quat, Quat );
}
bool BOTAI_WillHomingMissileHit(VECTOR * MyPos)
{
float Cos;
float Angle;
VECTOR DirVector;
VECTOR TmpVec;
QUATLERP qlerp;
SECONDARYWEAPONBULLET MissCopy = SecBulls[ HomingMissile ];
// direction vector from missile to me
DirVector.x = MyPos->x - MissCopy.Pos.x;
DirVector.y = MyPos->y - MissCopy.Pos.y;
DirVector.z = MyPos->z - MissCopy.Pos.z;
NormaliseVector( &DirVector );
// angle difference between the missile's current vector and wanted vector
Cos = DotProduct( &DirVector, &MissCopy.DirVector );
// set the parameters to perform a linear interpolation on two quaternions
QuatFrom2Vectors( &qlerp.end, &Forward, &DirVector );
qlerp.start = MissCopy.DirQuat;
qlerp.crnt = &MissCopy.DirQuat;
qlerp.dir = QuatDotProduct( &qlerp.start, &qlerp.end );
// bound angle difference
if( Cos < -1.0F ) Cos = -1.0F;
else if ( Cos > 1.0F ) Cos = 1.0F;
// get angle difference in radians
Angle = (float) acos( Cos );
// calculate the amount of angle to turn
if( Angle ) qlerp.time = ( ( D2R( MissCopy.TurnSpeed ) * framelag ) / Angle );
else qlerp.time = 1.0F;
if( qlerp.time > 1.0F ) qlerp.time = 1.0F;
// perform quat interpolation
QuatInterpolate( &qlerp );
QuatToMatrix( &MissCopy.DirQuat, &MissCopy.Mat );
ApplyMatrix( &MissCopy.Mat, &Forward, &MissCopy.DirVector );
ApplyMatrix( &MissCopy.Mat, &SlideUp, &MissCopy.UpVector );
// will missile hit?
if(RaytoSphere2(MyPos, SHIP_RADIUS, &MissCopy.Pos, &MissCopy.DirVector, &TmpVec, &TmpVec ))
{
DebugPrintf("homing missile will hit\n");
return true;
}
else
{
DebugPrintf("safe from homing missile\n");
return false;
}
}