/*
===============
idParticleStage::ParticleOrigin
===============
*/
void idParticleStage::ParticleOrigin( particleGen_t* g, idVec3& origin ) const
{
if( customPathType == PPATH_STANDARD )
{
//
// find intial origin distribution
//
float radiusSqr, angle1, angle2;
switch( distributionType )
{
case PDIST_RECT: // ( sizeX sizeY sizeZ )
{
origin[0] = ( ( randomDistribution ) ? g->random.CRandomFloat() : 1.0f ) * distributionParms[0];
origin[1] = ( ( randomDistribution ) ? g->random.CRandomFloat() : 1.0f ) * distributionParms[1];
origin[2] = ( ( randomDistribution ) ? g->random.CRandomFloat() : 1.0f ) * distributionParms[2];
break;
}
case PDIST_CYLINDER: // ( sizeX sizeY sizeZ ringFraction )
{
angle1 = ( ( randomDistribution ) ? g->random.CRandomFloat() : 1.0f ) * idMath::TWO_PI;
idMath::SinCos16( angle1, origin[0], origin[1] );
origin[2] = ( ( randomDistribution ) ? g->random.CRandomFloat() : 1.0f );
// reproject points that are inside the ringFraction to the outer band
if( distributionParms[3] > 0.0f )
{
radiusSqr = origin[0] * origin[0] + origin[1] * origin[1];
if( radiusSqr < distributionParms[3] * distributionParms[3] )
{
// if we are inside the inner reject zone, rescale to put it out into the good zone
float f = sqrt( radiusSqr ) / distributionParms[3];
float invf = 1.0f / f;
float newRadius = distributionParms[3] + f * ( 1.0f - distributionParms[3] );
float rescale = invf * newRadius;
origin[0] *= rescale;
origin[1] *= rescale;
}
}
origin[0] *= distributionParms[0];
origin[1] *= distributionParms[1];
origin[2] *= distributionParms[2];
break;
}
case PDIST_SPHERE: // ( sizeX sizeY sizeZ ringFraction )
{
// iterating with rejection is the only way to get an even distribution over a sphere
if( randomDistribution )
{
do
{
origin[0] = g->random.CRandomFloat();
origin[1] = g->random.CRandomFloat();
origin[2] = g->random.CRandomFloat();
radiusSqr = origin[0] * origin[0] + origin[1] * origin[1] + origin[2] * origin[2];
}
while( radiusSqr > 1.0f );
}
else
{
origin.Set( 1.0f, 1.0f, 1.0f );
radiusSqr = 3.0f;
}
if( distributionParms[3] > 0.0f )
{
// we could iterate until we got something that also satisfied ringFraction,
// but for narrow rings that could be a lot of work, so reproject inside points instead
if( radiusSqr < distributionParms[3] * distributionParms[3] )
{
// if we are inside the inner reject zone, rescale to put it out into the good zone
float f = sqrt( radiusSqr ) / distributionParms[3];
float invf = 1.0f / f;
float newRadius = distributionParms[3] + f * ( 1.0f - distributionParms[3] );
float rescale = invf * newRadius;
origin[0] *= rescale;
origin[1] *= rescale;
origin[2] *= rescale;
}
}
origin[0] *= distributionParms[0];
origin[1] *= distributionParms[1];
origin[2] *= distributionParms[2];
break;
}
}
// offset will effect all particle origin types
// add this before the velocity and gravity additions
origin += offset;
//
// add the velocity over time
//
idVec3 dir;
switch( directionType )
{
case PDIR_CONE:
{
// angle is the full angle, so 360 degrees is any spherical direction
angle1 = g->random.CRandomFloat() * directionParms[0] * idMath::M_DEG2RAD;
angle2 = g->random.CRandomFloat() * idMath::PI;
float s1, c1, s2, c2;
idMath::SinCos16( angle1, s1, c1 );
idMath::SinCos16( angle2, s2, c2 );
dir[0] = s1 * c2;
dir[1] = s1 * s2;
dir[2] = c1;
break;
}
case PDIR_OUTWARD:
{
dir = origin;
dir.Normalize();
dir[2] += directionParms[0];
break;
}
}
// add speed
float iSpeed = speed.Integrate( g->frac, g->random );
origin += dir * iSpeed * particleLife;
}
else
{
//
// custom paths completely override both the origin and velocity calculations, but still
// use the standard gravity
//
float angle1, angle2, speed1, speed2;
switch( customPathType )
{
case PPATH_HELIX: // ( sizeX sizeY sizeZ radialSpeed axialSpeed )
{
speed1 = g->random.CRandomFloat();
speed2 = g->random.CRandomFloat();
angle1 = g->random.RandomFloat() * idMath::TWO_PI + customPathParms[3] * speed1 * g->age;
float s1, c1;
idMath::SinCos16( angle1, s1, c1 );
origin[0] = c1 * customPathParms[0];
origin[1] = s1 * customPathParms[1];
origin[2] = g->random.RandomFloat() * customPathParms[2] + customPathParms[4] * speed2 * g->age;
break;
}
case PPATH_FLIES: // ( radialSpeed axialSpeed size )
{
speed1 = idMath::ClampFloat( 0.4f, 1.0f, g->random.CRandomFloat() );
speed2 = idMath::ClampFloat( 0.4f, 1.0f, g->random.CRandomFloat() );
angle1 = g->random.RandomFloat() * idMath::PI * 2 + customPathParms[0] * speed1 * g->age;
angle2 = g->random.RandomFloat() * idMath::PI * 2 + customPathParms[1] * speed1 * g->age;
float s1, c1, s2, c2;
idMath::SinCos16( angle1, s1, c1 );
idMath::SinCos16( angle2, s2, c2 );
origin[0] = c1 * c2;
origin[1] = s1 * c2;
origin[2] = -s2;
origin *= customPathParms[2];
break;
}
case PPATH_ORBIT: // ( radius speed axis )
{
angle1 = g->random.RandomFloat() * idMath::TWO_PI + customPathParms[1] * g->age;
float s1, c1;
idMath::SinCos16( angle1, s1, c1 );
origin[0] = c1 * customPathParms[0];
origin[1] = s1 * customPathParms[0];
origin.ProjectSelfOntoSphere( customPathParms[0] );
break;
}
case PPATH_DRIP: // ( speed )
{
origin[0] = 0.0f;
origin[1] = 0.0f;
origin[2] = -( g->age * customPathParms[0] );
break;
}
default:
{
common->Error( "idParticleStage::ParticleOrigin: bad customPathType" );
}
}
origin += offset;
}
// adjust for the per-particle smoke offset
origin *= g->axis;
origin += g->origin;
// add gravity after adjusting for axis
if( worldGravity )
{
idVec3 gra( 0, 0, -gravity );
gra *= g->renderEnt->axis.Transpose();
origin += gra * g->age * g->age;
}
else
{
origin[2] -= gravity * g->age * g->age;
}
}
