Method EmitParticles

trinity/Particle/Tr2GpuParticleSystem.cpp:562–598

-------------------------------------------------------------------------------------- Description: Emits new particles into the system. Uses constant buffer to pass emitter parameters to the shader. --------------------------------------------------------------------------------------

//   to the shader.
// --------------------------------------------------------------------------------------
void Tr2GpuParticleSystem::EmitParticles( Tr2RenderContext& renderContext )
{
	struct EmitterCBPrefix
	{
		uint32_t count;
		float padding[3];
	};

	static const size_t maxSize = TRINITY_PLATFORM_MAX_CONSTANT_BUFFER_SIZE;
	static const size_t emitsPerDispatch = ( maxSize - sizeof( EmitterCBPrefix ) ) / sizeof( EmitterGpu );
	struct CB
	{
		EmitterCBPrefix prefix;
		EmitterGpu emitters[emitsPerDispatch];
	} cb;

	m_emitTimer.Begin( renderContext );
	ON_BLOCK_EXIT( [&] { m_emitTimer.End( renderContext ); } );

	for( size_t i = 0; i < m_emitRequests.GetCount(); i += emitsPerDispatch )
	{
		cb.prefix.count = uint32_t( std::min( m_emitRequests.GetCount() - i, emitsPerDispatch ) );
		for( size_t j = 0; j < cb.prefix.count; ++j )
		{
			cb.emitters[j] = m_emitRequests[i + j].emitter;
		}
		FillAndSetConstants(
			m_emitCB,
			&cb,
			sizeof( EmitterCBPrefix ) + cb.prefix.count * sizeof( EmitterGpu ),
			Tr2RenderContextEnum::COMPUTE_SHADER,
			Tr2Renderer::GetPerObjectVSStartRegister(),
			renderContext );

		Tr2Renderer::RunComputeShader( m_emit, cb.prefix.count, 1, 1, renderContext );
	}
}

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