Function buildContour

TheForceEngine/TFE_Polygon/polygon.cpp:884–941

	}
			
	bool buildContour(const BEdge* startEdge, const std::vector<BEdge>& edgesList, std::vector<s32>& remEdges, Contour* outContour)
	{
		if (!outContour) { return false; }
		outContour->vtx.clear();

		Vec2f startPt = startEdge->v0;
		s32 nextEdge = startEdge->nextEdge;
		outContour->vtx.push_back(startPt);
		// Loop until the end or we are back at the start.
		while (!remEdges.empty())
		{
			const BEdge* edge = &edgesList[nextEdge];
			if (vtxEqual(&edge->v0, &startPt))
			{
				// Vertex with 3+ edges intersecting.
				break;
			}
			outContour->vtx.push_back(edge->v0);

			// Erase the remaining edge.
			const s32 remEdgeCount = (s32)remEdges.size();
			const s32* remIdx = remEdges.data();
			bool foundEdge = false;
			for (s32 i = 0; i < remEdgeCount; i++)
			{
				if (remIdx[i] == nextEdge)
				{
					remEdges.erase(remEdges.begin() + i);
					foundEdge = true;
					break;
				}
			}
			// There is a loop in the contour.
			if (!foundEdge)
			{
				break;
			}
			nextEdge = edge->nextEdge;

			// Reached the end.
			if (vtxEqual(&edge->v1, &startPt))
			{
				break;
			}
		}

		// No valid contour.
		if (outContour->vtx.empty())
		{
			return false;
		}

		// Next determine the winding order.
		const f32 area = TFE_Polygon::signedArea((s32)outContour->vtx.size(), outContour->vtx.data());
		outContour->clockwise = (area >= 0.0f);
		outContour->outsideClip = false;
		return true;
	}