Function canRemoveVertex

Source/ThirdParty/recastnavigation/RecastMesh.cpp:563–661

}

static bool canRemoveVertex(rcContext* ctx, rcPolyMesh& mesh, const unsigned short rem)
{
	const int nvp = mesh.nvp;
	
	// Count number of polygons to remove.
	int numTouchedVerts = 0;
	int numRemainingEdges = 0;
	for (int i = 0; i < mesh.npolys; ++i)
	{
		unsigned short* p = &mesh.polys[i*nvp*2];
		const int nv = countPolyVerts(p, nvp);
		int numRemoved = 0;
		int numVerts = 0;
		for (int j = 0; j < nv; ++j)
		{
			if (p[j] == rem)
			{
				numTouchedVerts++;
				numRemoved++;
			}
			numVerts++;
		}
		if (numRemoved)
		{
			numRemainingEdges += numVerts-(numRemoved+1);
		}
	}
	
	// There would be too few edges remaining to create a polygon.
	// This can happen for example when a tip of a triangle is marked
	// as deletion, but there are no other polys that share the vertex.
	// In this case, the vertex should not be removed.
	if (numRemainingEdges <= 2)
		return false;
	
	// Find edges which share the removed vertex.
	const int maxEdges = numTouchedVerts*2;
	int nedges = 0;
	rcScopedDelete<int> edges((int*)rcAlloc(sizeof(int)*maxEdges*3, RC_ALLOC_TEMP));
	if (!edges)
	{
		ctx->log(RC_LOG_WARNING, "canRemoveVertex: Out of memory 'edges' (%d).", maxEdges*3);
		return false;
	}
		
	for (int i = 0; i < mesh.npolys; ++i)
	{
		unsigned short* p = &mesh.polys[i*nvp*2];
		const int nv = countPolyVerts(p, nvp);

		// Collect edges which touches the removed vertex.
		for (int j = 0, k = nv-1; j < nv; k = j++)
		{
			if (p[j] == rem || p[k] == rem)
			{
				// Arrange edge so that a=rem.
				int a = p[j], b = p[k];
				if (b == rem)