Support for rendering large point clouds

[fwilliams]

Hi,

This seems like a great visualization tool for 3D problems! It would be nice to have some support for rendering large colored and lit point clouds. I tried adding spheres to a scene (one per point) but this slowed down very quickly for even a moderately large number of spheres (~10-50k). It would be nice to have support for rendering very large point clouds!

[matajoh]

We absolutely support this! We have some examples in the tutorial for point clouds:

C++ tutorial:

scenepic/src/examples/tutorial.cpp

Lines 106 to 129 in f695a29

	void point_clouds_1()
	{
	std::cout << "== Point Clouds 1 ==" << std::endl;
	// Create a scene
	sp::Scene scene;
	// Create a mesh that we'll turn in to a point-cloud using enable_instancing()
	auto mesh = scene.create_mesh();
	mesh->shared_color(sp::Color(0, 1, 0));
	mesh->add_cube();
	mesh->apply_transform(sp::Transforms::scale(0.01f));
	sp::VectorBuffer positions = sp::random<sp::VectorBuffer>(10000, 3, 0, 1);
	positions = (2 * positions).array() - 1;
	mesh->enable_instancing(positions);
	// Create Canvas and Frame, and add Mesh to Frame
	auto canvas = scene.create_canvas_3d("", 300, 300);
	canvas->shading(sp::Shading(sp::Colors::White));
	auto frame = canvas->create_frame();
	frame->add_mesh(mesh);
	scene.save_as_html("point_clouds_1.html", "Point Clouds 1");
	}

Python tutorial (also in the Jupyter notebook of course):

scenepic/test/test_tutorial.py

Lines 49 to 59 in f695a29

	scene = sp.Scene()
	mesh = scene.create_mesh(shared_color=sp.Color(0, 1, 0))
	mesh.add_cube()
	mesh.apply_transform(sp.Transforms.Scale(0.01))
	mesh.enable_instancing(positions=2 * np.random.rand(10000, 3) - 1)
	canvas = scene.create_canvas_3d(
	width=300, height=300, shading=sp.Shading(bg_color=sp.Colors.White))
	frame = canvas.create_frame()
	frame.add_mesh(mesh)

The key thing is to use the enable_instancing function on the mesh. It should be able to support as much as your graphics card can handle. Please let me know if this resolves your issue.

[fwilliams]

Thanks! This does work for me. I somehow missed the tutorial. I couldn't find a link in the main documentation. It would be really great to have a more fleshed out tutorial in the main documentation, but I'm sure this will happen eventually. Thanks for the cool library!

[matajoh]

Great feedback! We'll work on making this more front and center in our documentation, as it is a very common use case. Thanks!