/**
* This method generates the vectors for CylinderVectorGenerator.
*
* @param vector Vector to be over-written with the new vector.
*/
void CylinderVectorGenerator::generate( Vector3 &vector ) const
{
BW_GUARD;
// Get a point along the axis of the cylinder.
vector = origin_ + unitRand() * direction_;
// Make sure that the radii are sorted:
float minR = minRadius_;
float maxR = maxRadius_;
if (minR > maxR)
std::swap(minR, maxR);
// Choosing points in a disc uniformly is not as easy as you may first
// think. Choosing the angle and radius randomly gives a distribution
// concentrated at the center. A correct formula is given by:
// http://mathworld.wolfram.com/DiskPointPicking.html
// Here we adjust for the fact that we are not on the unit disc, but on
// an annulus. To do this we convert the radius range from
// [minRadius_, maxRadius] to [alpha, 1.0] where
// alpha = minRadius_/maxRadius_, do the sqrt random distribution and
// then convert back to the range [minRadius_, maxRadius].
float angle = unitRand() * 2.0f * MATH_PI;
float r;
if (minR == maxR) // handle case where radii are equal (or both zero)
{
r = minR;
}
else
{
float alpha = minR/maxR;
float k1 = std::sqrtf( unitRand() * ( 1.0f - alpha ) + minR );
r = Math::lerp( k1, alpha, 1.0f, minR, maxR );
}
vector += r * ( std::cosf( angle ) * basisU_ + std::sinf( angle ) * basisV_ );
}
void DenseMatrix<Complex> :: randomize( void )
// replaces entries with uniformly distributed real random numbers in the interval [-1,1]
{
for( int i = 0; i < m*n; i++ )
{
data[i].re = 2.*unitRand() - 1.;
data[i].im = 2.*unitRand() - 1.;
}
}
void DenseMatrix<Quaternion> :: randomize( void )
// replaces entries with uniformly distributed real random numbers in the interval [-1,1]
{
for( int i = 0; i < m*n; i++ )
{
for( int k = 0; k < 4; k++ )
{
data[i][k] = 2.*unitRand() - 1.;
}
}
}
/**
* This method generates the vectors for SphereVectorGenerator.
*
* @param vector Vector to be over-written with the new vector.
*/
void SphereVectorGenerator::generate( Vector3 &vector ) const
{
// Generate a random point on the unit sphere
// (based upon http://mathworld.wolfram.com/SpherePointPicking.html):
float theta = 2.0f * MATH_PI * unitRand();
float phi = std::acosf( 2.0f * unitRand() - 1.0f );
float sinphi = std::sinf( phi );
float x = std::cosf( theta ) * sinphi;
float y = std::sinf( theta ) * sinphi;
float z = std::cosf( phi );
vector = Vector3(x, y, z);
// Make sure that the radii are sorted:
float minR = minRadius_;
float maxR = maxRadius_;
if (minR > maxR)
std::swap(minR, maxR);
// Choose a random radius, taking into account that spherical shells
// go as r^2 dr (integrate to give the volume of the shell and then
// bias the choice of radius based upon that).
float r;
if (minR == maxR) // handle case where radii are equal (or both zero)
{
r = minR;
}
else
{
float alpha = minR / maxR;
float k1 = std::powf( unitRand() * ( 1.0f - alpha ) + minR , 1.0f/3.0f);
r = Math::lerp( k1, alpha, 1.0f, minR, maxR );
}
// Scale the point to the sphere we want and move it into position.
vector = r*vector + centre_;
}
/**
* This method executes the action for the given frame of time. The dTime
* parameter is the time elapsed since the last call.
*
* @param particleSystem The particle system on which to operate.
* @param dTime Elapsed time in seconds.
*/
void CollidePSA::execute( ParticleSystem &particleSystem, float dTime )
{
BW_GUARD;
SourcePSA* pSource = static_cast<SourcePSA*>( &*particleSystem.pAction( PSA_SOURCE_TYPE_ID ) );
if ( !pSource )
return;
RompColliderPtr pGS = pSource->groundSpecifier();
if ( !pGS )
return;
uint64 tend = timestamp() + stampsPerSecond() / 2000;
bool soundHit = false;
float maxVelocity = 0;
Vector3 soundPos;
uint materialKind;
Particles::iterator it = particleSystem.begin();
Particles::iterator end = particleSystem.end();
WorldTriangle tri;
//bust out of the loop if we take more than 0.5 msec
//Sprite particles don't calculate spin
while ( it != end && timestamp()<tend )
{
Particle &particle = *it++;
if (!particle.isAlive())
{
continue;
}
//note - particles get moved after actions.
Vector3 velocity;
particle.getVelocity(velocity);
Vector3 pos;
Vector3 newPos;
if(particleSystem.isLocal())
{
Matrix world = particleSystem.worldTransform();
pos = world.applyPoint(particle.position());
Vector3 nPos;
particleSystem.predictPosition( particle, dTime, nPos );
newPos = world.applyPoint(nPos);
}
else
{
pos = particle.position();
particleSystem.predictPosition( particle, dTime, newPos );
}
float tValue = pGS->collide( pos, newPos, tri );
if ( tValue >= 0.f && tValue <= 1.f )
{
// calc v as a dotprod of the two normalised vectors (before and after collision)
Vector3 oldVel = velocity / velocity.length();
tri.bounce( velocity, elasticity_ );
particle.setVelocity( velocity );
float newSpeed = velocity.length();
Vector3 newVel(velocity / newSpeed);
float severity = oldVel.dotProduct(newVel);
//DEBUG_MSG("severity: %1.3f, speed=%1.3f\n", severity, newSpeed);
float v = (1 - severity) * newSpeed;
//now spin the particle ( mesh only )
if ( !spriteBased_ )
{
//first, calculate the current rotation, and update the pitch/yaw value.
Matrix currentRot;
currentRot.setRotate( particle.yaw(), particle.pitch(), 0.f );
Matrix spin;
float spinSpeed = particle.meshSpinSpeed();
Vector3 meshSpinAxis = particle.meshSpinAxis();
// If there is no spin direction then creating a rotation
// matrix can create weird matrices - e.g. matrices with
// negative scale components and a translation. We choose the
// velocity as the spin direction (aribitrarily choosing, for
// example up looks weird).
if (meshSpinAxis == Vector3::zero())
{
meshSpinAxis = velocity;
meshSpinAxis.normalise();
}
D3DXMatrixRotationAxis
(
&spin,
&meshSpinAxis,
spinSpeed * (particle.age()-particle.meshSpinAge())
);
currentRot.preMultiply( spin );
particle.pitch( currentRot.pitch() );
particle.yaw( currentRot.yaw() );
//now, reset the age of the spin
particle.meshSpinAge( particle.age() );
//finally, update the spin ( stored in the particle's colour )
float addedSpin = unitRand() * (maxAddedRotation_-minAddedRotation_) + minAddedRotation_;
addedSpin *= min( newSpeed, 1.f );
spinSpeed = Math::clamp( 0.f, spinSpeed + addedSpin, 1.f );
particle.meshSpinSpeed(spinSpeed);
particle.meshSpinAxis(meshSpinAxis);
}
if ( soundEnabled_ && v > 0.5f )
{
soundHit = true;
if (v > maxVelocity) {
maxVelocity = v;
soundPos = particle.position();
materialKind = tri.materialKind();
}
}
}
}
if ( soundHit )
{
SmartPointer < RompSound > rs = RompSound::getProvider();
if (rs)
{
if (!soundTag_.empty())
{
rs->playParticleSound( soundTag_.c_str(), soundPos, maxVelocity, soundSrcIdx_, materialKind );
}
}
}
}
/**
* This method generates the vectors for BoxVectorGenerator.
*
* @param vector Vector to be over-written with the new vector.
*/
void BoxVectorGenerator::generate( Vector3 &vector ) const
{
vector.set( corner_.x + unitRand() * ( opposite_.x - corner_.x ),
corner_.y + unitRand() * ( opposite_.y - corner_.y ),
corner_.z + unitRand() * ( opposite_.z - corner_.z ) );
}
/**
* This function returns a uniform random number in the input range.
*/
inline float randInRange( float min, float max )
{
return min + unitRand() * (max - min);
}
