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Code Block
{ 3, 0, 1, 2,
  3, 2, 3, 0 }

\uD83D\uDCD8 Instructions

Simple Example

Lets assume we have a single polygon with 300 points (nb_circle_steps). This is all in one “face”. So, the correct code for this would be

Code Block
	std::vector<int> face_list;
	face_list.push_back(nb_circle_steps);
	for (uint32_t i = 0; i < nb_circle_steps; i++)
		face_list.push_back(i);

	std::vector<SC::Store::Point> out_points;
	bool triStatus = SC::Store::Utils::TriangulateFace(mesh_points.data(), face_list.data(), face_list.size(), SC::Store::Point(0, 0, 1), out_points);
	if (triStatus)
        std::cout << "TriangulateFace : out_points count = " << out_points.size() << std::endl;
	else
        std::cout << "TriangulateFace : failed" << std::endl;
Info

Notice face_list.size() is used as an argument to TriagulateFace rather than nb_circle_steps.

Concave Faces

This is the only triangulation function available in Communicator and it handles concave polygons. Consider this simple test.

Code Block
	int point_count = 5;
	std::vector<int> face_list;
	face_list.push_back(point_count);
	for (uint32_t i = 0; i < point_count; i++)
		face_list.push_back(i);

    std::vector<SC::Store::Point> poly_points;
    poly_points.resize(point_count);
	poly_points[0].x = 0;
	poly_points[0].y = 0;
	poly_points[0].z = 0;
	poly_points[1].x = 1;
	poly_points[1].y = 1;
	poly_points[1].z = 0;
	poly_points[2].x = 2;
	poly_points[2].y = 0;
	poly_points[2].z = 0;
	poly_points[3].x = 1;
	poly_points[3].y = 2;
	poly_points[3].z = 0;
	poly_points[4].x = 0;
	poly_points[4].y = 0;
	poly_points[4].z = 0;

	std::vector<SC::Store::Point> out_points;
	bool triStatus = SC::Store::Utils::TriangulateFace(poly_points.data(), face_list.data(), face_list.size(), SC::Store::Point(0, 0, 1), out_points);

The result was

Code Block
+		[0]	{x=1.00000000 y=2.00000000 z=0.00000000 }	SC::Store::Point
+		[1]	{x=0.00000000 y=0.00000000 z=0.00000000 }	SC::Store::Point
+		[2]	{x=1.00000000 y=1.00000000 z=0.00000000 }	SC::Store::Point
+		[3]	{x=1.00000000 y=2.00000000 z=0.00000000 }	SC::Store::Point
+		[4]	{x=1.00000000 y=1.00000000 z=0.00000000 }	SC::Store::Point
+		[5]	{x=2.00000000 y=0.00000000 z=0.00000000 }	SC::Store::Point

Faces with Holes

This method supports holes as well. It expects more than one face passed in where one face represents the perimeter and subsequent faces represent holes. Simply negate the first parameter in the face list for a face which represents a hole.

Code Block
	int perim_count = 4;
	int hole_count = 4;
	int point_count = perim_count + hole_count;
	std::vector<int> face_list;
	for (uint32_t i = 0; i < point_count; i++)
	{
		if (i == 0)
			face_list.push_back(perim_count);
		else if (i == 4)
			face_list.push_back(-hole_count); // negated parameter indicates this face is a hole

		face_list.push_back(i);
	}

    std::vector<SC::Store::Point> poly_points;
	poly_points.push_back(SC::Store::Point(0, 0, 0)); // perimeter
	poly_points.push_back(SC::Store::Point(3, 0, 0));
	poly_points.push_back(SC::Store::Point(3, 3, 0));
	poly_points.push_back(SC::Store::Point(0, 3, 0));
	poly_points.push_back(SC::Store::Point(1, 1, 0)); // hole
	poly_points.push_back(SC::Store::Point(2, 1, 0));
	poly_points.push_back(SC::Store::Point(2, 2, 0));
	poly_points.push_back(SC::Store::Point(1, 2, 0));

	std::vector<SC::Store::Point> out_points;
	bool triStatus = SC::Store::Utils::TriangulateFace(poly_points.data(), face_list.data(), face_list.size(), SC::Store::Point(0, 0, 1), out_points);
	if (triStatus)
		std::cout << "TriangulateFace : out_points count = " << out_points.size() << std::endl;
	else
		std::cout << "TriangulateFace : failed" << std::endl;

...

For the full example, check out our forum post.