Angle Vector2D::getAngleTo(const Vector2D& other) const
{
// A·B = |A| * |B| * cos θ, θ = arccos (A·B / (|A| * |B|))
// NB that A·B / (|A| * |B|) cannot generate an invalid value for Math::acos
// because of the Cauchy-Schwarz inequality
return Radian(Math::acos(dot(other) / (getLength() * other.getLength())));
}
Steering* DynamicArriveSteering::getSteering()
{
Vector2D direction = mpTarget->getPosition() - mpMover->getPosition();
float distance = direction.getLength();
//are we there?
if( distance < mTargetRadius )
{
mLinear = gZeroVector2D;
mAngular = 0.0f;
return this;
}
float targetSpeed = 0.0f;
//are we outside slow radius?
if( distance > mSlowRadius )
{
targetSpeed = mpMover->getMaxVelocity();
}
else
{
targetSpeed = ( mpMover->getMaxVelocity() * distance ) / mSlowRadius;
}
//combine speed and direction to get targetVelocity
Vector2D targetVelocity = direction;
targetVelocity.normalize();
targetVelocity *= targetSpeed;
//set acceleration
mLinear = targetVelocity - mpMover->getVelocity();
mLinear /= mTimeToTarget;
//check if too fast
if( mLinear.getLength() > mpMover->getMaxAcceleration() )
{
//cut down to max
mLinear.normalize();
mLinear*= mpMover->getMaxAcceleration();
}
mAngular = 0.0f;
return this;
}
Steering* WanderAndSeekOrFlee::getSteering()
{
Vector2D direction = mpTarget->getPosition() - mpMover->getPosition();
float distance = direction.getLength();
ALLEGRO_COLOR color;
if (mShouldFlee)
color = al_map_rgb(0, 0, 0);
else
color = al_map_rgb(0, 191, 255);
if (debugOn)
al_draw_circle(mpMover->getPosition().getX(), mpMover->getPosition().getY(), mRadius, color, 2.0f);
if (distance > mRadius)
return mpDynamicWanderSteering->getSteering();
else
return mpDynamicSeekSteering->getSteering();
}
