Method SortParticles

trinity/Particle/Tr2ParticleSystem.cpp:1067–1136

}

void Tr2ParticleSystem::SortParticles()
{
	USE_MAIN_THREAD_RENDER_CONTEXT();
	if( !m_bufferDirty && !m_requiresSorting )
	{
		return;
	}

	if( !m_vertexBuffer.IsValid() )
	{
		return;
	}

	XMMATRIX invWorldTransform = m_worldTransform;
	XMVECTOR determinant;
	invWorldTransform = XMMatrixInverse( &determinant, invWorldTransform );

	const float sortingPointEpsilon = 0.001f;
	XMVECTOR sortingReferencePoint = XMVector3TransformCoord( Tr2Renderer::GetViewPosition(), invWorldTransform );
	XMVECTOR lengthSq = XMVector3LengthSq( XMVectorSubtract( sortingReferencePoint, *m_sortingReferencePoint ) );
	if( !m_bufferDirty && XMVectorGetX( lengthSq ) < sortingPointEpsilon )
	{
		return;
	}
	*m_sortingReferencePoint = sortingReferencePoint;

	if( m_aliveCount > 0 )
	{
		if( m_shouldSortVisible && m_sortingAllowed && m_requiresSorting && HasElement( Tr2ParticleElementDeclarationName::POSITION ) )
		{
			for( unsigned i = 0; i < m_aliveCount; ++i )
			{
				m_indexes[i] = i;
			}

			Tr2ParallelSort(
				m_indexes,
				m_indexes + m_aliveCount,
				[=]( unsigned particle1, unsigned particle2 ) -> bool {
					return CompareParticles( particle1, particle2 );
				} );

			if( m_vertexBuffer.IsValid() )
			{
				float* data;
				CR_RETURN( m_vertexBuffer.MapForWriting( data, renderContext ) );
				ON_BLOCK_EXIT( [&] { m_vertexBuffer.UnmapForWriting( renderContext ); } );
				for( unsigned i = 0; i < m_aliveCount; ++i )
				{
					std::copy(
						m_buffers[Tr2ParticleElementData::GPU] + m_indexes[i] * m_vertexSizes[Tr2ParticleElementData::GPU],
						m_buffers[Tr2ParticleElementData::GPU] + ( m_indexes[i] + 1 ) * m_vertexSizes[Tr2ParticleElementData::GPU],
						data + i * m_vertexSizes[Tr2ParticleElementData::GPU] );
				}
			}
		}
		else if( m_vertexBuffer.IsValid() )
		{