Method RebuildGeometry

trinity/Eve/UI/EveEllipseSet.cpp:241–359

}

void EveEllipseSet::RebuildGeometry( const EveUpdateContext& updateContext )
{
	m_indexCount = 0;

	BoundingSphereInitialize( m_boundingSphere );

	const unsigned int segmentCount = std::max( 16u, std::min( 512u, m_ribbonSegmentCount ) );
	const unsigned int ellipseCount = static_cast<unsigned int>( m_ellipses.size() );
	const uint32_t vertexCount = ellipseCount * 2u * segmentCount;
	const uint32_t indexCount = ellipseCount * 6u * segmentCount;

	if( ellipseCount == 0 )
	{
		m_vertexBuffer = Tr2BufferAL();
		m_indexBuffer = Tr2BufferAL();
		m_geometryDirty = false;
		return;
	}

	TriPoolAllocator* allocator = Tr2Renderer::GetPoolAllocator();
	if( !allocator )
	{
		return;
	}

	auto vertices = reinterpret_cast<EllipseVertex*>( allocator->Allocate( vertexCount * sizeof( EllipseVertex ) ) );
	auto indices = reinterpret_cast<uint32_t*>( allocator->Allocate( indexCount * sizeof( uint32_t ) ) );
	if( !vertices || !indices )
	{
		return;
	}

	uint32_t vWrite = 0;
	uint32_t iWrite = 0;

	// Screen-space billboard ribbon: store centerline + tangent; VS expands to pixel width at draw time.
	for( auto& spec : m_ellipses )
	{
		Vector3 semiMajorAxis, semiMinorAxis;
		BuildOrbitEllipseAxes( *spec, semiMajorAxis, semiMinorAxis );

		const Vector3& center = spec->m_center;
		const float semiMajor = std::max( spec->m_semiMajor, 1e-4f );
		const float semiMinor = std::max( spec->m_semiMinor, 1e-4f );

		const uint32_t baseVertexIndex = vWrite;

		for( unsigned int i = 0; i < segmentCount; ++i )
		{
			const float angle = ( static_cast<float>( i ) / static_cast<float>( segmentCount ) ) * ( 2.f * TRI_PI );
			const float cosAngle = cosf( angle );
			const float sinAngle = sinf( angle );
			const Vector3 point = center + semiMajorAxis * ( semiMajor * cosAngle ) + semiMinorAxis * ( semiMinor * sinAngle );
			Vector3 tangent = semiMajorAxis * ( -semiMajor * sinAngle ) + semiMinorAxis * ( semiMinor * cosAngle );
			float tangentLength = Length( tangent );
			if( tangentLength < 1e-12f )
			{
				tangent = semiMajorAxis;