Method RebuildDeclaration

trinity/Particle/Tr2ParticleSystem.cpp:884–928

-------------------------------------------------------------------------------------- Description: Rebuilds D3D vertex declaration. --------------------------------------------------------------------------------------

//   Rebuilds D3D vertex declaration.
// --------------------------------------------------------------------------------------
void Tr2ParticleSystem::RebuildDeclaration()
{
	Tr2VertexDefinition vd;

	for( auto it = m_elementMap.begin(); it != m_elementMap.end(); ++it )
	{
		//Skip things we don't want to upload to the GPU
		if( it->second.m_bufferType != Tr2ParticleElementData::GPU )
		{
			continue;
		}

		Tr2VertexDefinition::Item item;
		item.m_stream = 0;
		item.m_offset = it->second.m_offset * sizeof( float );
		item.m_dataType = static_cast<Tr2VertexDefinition::DataType>( vd.DT_FLOAT32 + ( ( it->second.m_dimension - 1 ) << vd.DT_SIZE_OFFSET ) );
		item.m_usage = it->first.GetD3DUsage();

		item.m_usageIndex = it->first.m_type == Tr2ParticleElementDeclarationName::CUSTOM ? it->second.m_usageIndex : 0;

		vd.m_items.push_back( item );
		vd.m_nextOffset[0] = std::max( vd.m_nextOffset[0], item.m_offset + vd.GetDataTypeSizeInBytes( item.m_dataType ) );

		/*
		Since we need to upload both the current and previous frame's data,
		we duplicate the vertex attributes with an offset. This allows the shader to access
		both the current data and the previous data simultaneously.

		Since CUSTOM vertex attributes can't be updated, we only need to duplicate the non-CUSTOM
		attributes. However, for simplicity, all the previous frame particle GPU data is tracked,
		so this could be added in the future if necessary.
		*/

		if( it->first.m_type != Tr2ParticleElementDeclarationName::CUSTOM )
		{
			item.m_usageIndex = 1;
			item.m_offset += m_vertexSizes[Tr2ParticleElementData::GPU] * sizeof( float ) / 2;

			vd.m_items.push_back( item );
			vd.m_nextOffset[0] = std::max( vd.m_nextOffset[0], item.m_offset + vd.GetDataTypeSizeInBytes( item.m_dataType ) );
		}
	}

	m_declaration = Tr2EffectStateManager::GetVertexDeclarationHandle( vd );
}

// --------------------------------------------------------------------------------------
// Description: