Method Rebuild

trinity/Eve/Renderable/EveSceneStaticParticles.cpp:225–328

-------------------------------------------------------------------------------- Description: Distributes particles in the clusters. --------------------------------------------------------------------------------

//   Distributes particles in the clusters.
// --------------------------------------------------------------------------------
void EveSceneStaticParticles::Rebuild()
{
	if( !m_mesh )
	{
		return;
	}

	// this object must have been set via python
	Tr2RuntimeInstanceData* instanceData = GetInstanceDataObject();
	if( !instanceData )
	{
		return;
	}

	// setup particle system
	Tr2VertexDefinition particleBufferVtxDef;
	particleBufferVtxDef.Add( Tr2VertexDefinition::FLOAT32_3, Tr2VertexDefinition::POSITION );
	particleBufferVtxDef.Add( Tr2VertexDefinition::FLOAT32_1, Tr2VertexDefinition::TEXCOORD, 0 );
	particleBufferVtxDef.Add( Tr2VertexDefinition::FLOAT32_4, Tr2VertexDefinition::TEXCOORD, 1 );
	instanceData->SetLayout( particleBufferVtxDef );

	// need total radius and a center for all clusters
	m_centerOfClusters = Vector3d( 0.0, 0.0, 0.0 );
	for( auto it = m_clusters.begin(); it != m_clusters.end(); ++it )
	{
		const ClusterData* clusterData = &( *it );
		m_centerOfClusters += Vector3d( (double)clusterData->position.x, (double)clusterData->position.y, (double)clusterData->position.z );
	}
	m_centerOfClusters /= (double)m_clusters.size();

	// need total size of particle buffer
	size_t particleBufferSize = 0;
	for( auto it = m_clusters.begin(); it != m_clusters.end(); ++it )
	{
		const ClusterData* clusterData = &( *it );
		particleBufferSize += size_t( m_clusterParticleDensity * clusterData->radius );
	}

	// are we too big? Too many particles? Do we need to adjust?
	m_clusterParticleDensityAdjust = 1.f;
	if( particleBufferSize > m_maxParticleCount )
	{
		m_clusterParticleDensityAdjust = float( m_maxParticleCount ) / float( particleBufferSize );
	}

	// count particle buffer size again, this time with adjustment
	particleBufferSize = 0;
	for( auto it = m_clusters.begin(); it != m_clusters.end(); ++it )
	{
		const ClusterData* clusterData = &( *it );
		particleBufferSize += size_t( m_clusterParticleDensityAdjust * m_clusterParticleDensity * clusterData->radius );
	}

	// alloc big buffer in the particle system
	ParticleBufferItem* currentParticleBufferItem = static_cast<ParticleBufferItem*>( instanceData->GetData( (unsigned int)particleBufferSize ) );

	// run over all the clusters and build
	for( auto it = m_clusters.begin(); it != m_clusters.end(); ++it )