Method UpdateFogEnvironmentMap

trinity/Tr2VolumetricsRenderer.cpp:406–491

void Tr2VolumetricsRenderer::UpdateFogEnvironmentMap( Tr2RenderContext& renderContext )
{
	bool froxelsEnabled = m_froxelFogSettings.thickness.value > 0.0f;
	bool environmentLightingEnabled = froxelsEnabled && m_froxelFogSettings.environmentIntensity.value > 0;


	uint32_t environmentMapResolution = 1;
	if( environmentLightingEnabled )
	{
		environmentMapResolution = 128;

		CCP_ASSERT( environmentMapResolution % 8 == 0 );
	}

	auto& mieEnvironmentMap = *m_mieEnvironmentMap->GetTexture();
	if( !mieEnvironmentMap.IsValid() || mieEnvironmentMap.GetWidth() != environmentMapResolution )
	{
		USE_MAIN_THREAD_RENDER_CONTEXT();

		m_environmentBlendCounter = 0; //reset counter so we start back from 0 when we enabled it next time.

		if( environmentLightingEnabled )
		{
			//Full 32-bit precision is needed due to blending to this texture with a low weight.
			Tr2BitmapDimensions dimensions( Tr2RenderContextEnum::TEX_TYPE_CUBE, Tr2RenderContextEnum::PIXEL_FORMAT_R32G32B32A32_FLOAT, environmentMapResolution, environmentMapResolution, 1, 1, 6 );

			mieEnvironmentMap.Create( dimensions, Tr2GpuUsage::UNORDERED_ACCESS | Tr2GpuUsage::SHADER_RESOURCE, renderContext );
		}
		else
		{
			//Create dummy texture
			Tr2BitmapDimensions dimensions( Tr2RenderContextEnum::TEX_TYPE_CUBE, Tr2RenderContextEnum::PIXEL_FORMAT_R8G8B8A8_UNORM, 1, 1, 1, 1, 6 );

			uint8_t black[4] = {};
			Tr2SubresourceData initialData[6];
			for( uint32_t i = 0; i < 6; ++i )
			{
				initialData[i].m_sysMem = black;
				initialData[i].m_sysMemPitch = 4;
				initialData[i].m_sysMemSlicePitch = 4;
			}

			mieEnvironmentMap.Create( dimensions, Tr2GpuUsage::UNORDERED_ACCESS | Tr2GpuUsage::SHADER_RESOURCE, initialData, renderContext );
		}
		if( !mieEnvironmentMap.IsValid() )
		{
			CCP_LOGERR( "Tr2VolumetricsRenderer failed to create environment cubemap with size %ix", int( environmentMapResolution ) );
			return;
		}

		m_mieEnvironmentMap->OnTextureChange().Broadcast();
	}

	if( environmentLightingEnabled )
	{
		GPU_REGION( renderContext, "Update Fog Environment Map" );

		const float g = 1.61803398874989484820;