RotatingPointcloud

Overview

class RotatingPointcloud : public omdi::examples::Sim

Built-in example simulation that animates one or more rotating 2D point clouds.

omdi::examples::RotatingPointcloud manages a set of named point groups, each containing a fixed number of randomly distributed 2D points. On each update() call the groups are rotated by an angle proportional to the elapsed time, producing a smooth spinning animation. The resulting omdi::Points objects are returned by get_data() and can be passed directly to omdi::ScatterPlot.

It is a convenient starting point for testing and demonstrating omdi::ScatterPlot with live, time-varying data.

Usage example

#include <omdi.hpp>

// Construct with a list of (name, npoints) pairs
auto sim = omdi::examples::RotatingPointcloud({
  { "group A", 500 },
  { "group B", 300 }
});

// Create a ScatterPlot to display the point clouds
auto scatter = omdi::ScatterPlot { "Pointcloud", sim.get_data() };

// Inside the render loop:
auto timer = omdi::Timer();

app.Render(&state, [&]() {
  sim.update(timer.elapsed(), timer.delta());
  scatter.update_all(sim.get_data());
  scatter.plot();
  timer.tick();
}, components, managers);

Constructor

RotatingPointcloud::RotatingPointcloud(const std::vector<std::pair<std::string, size_t>> &groups)

Construct a RotatingPointcloud simulation.

Parameters:

groups – List of (name, npoints) pairs. For each pair a group of npoints randomly positioned 2D points is created and associated with the given name.

Public interface

void RotatingPointcloud::update(double time, double delta)

Advance the simulation by one step.

Rotates every point group by an angle derived from the current time, producing continuous rotation. The updated positions are stored internally and can be retrieved with get_data().

Parameters:

• time – Absolute simulation time (seconds).

• delta – Time elapsed since the last update (seconds). Currently unused by the built-in implementation but forwarded for compatibility with omdi::examples::Sim.

auto RotatingPointcloud::n_groups() const -> size_t

Return the number of named point groups managed by this simulation.

Returns:

Number of (name, npoints) pairs passed to the constructor.

auto RotatingPointcloud::get_data() const -> std::map<std::string, omdi::Points>

Return the current point data for all groups.

Returns:

A map from group name to the corresponding omdi::Points, containing the most recently computed point positions. The map is returned by value; the caller owns the result.

Notes

• The returned map from get_data() can be passed directly to omdi::ScatterPlot::update_all() to refresh all series at once.

• Initial point positions are randomized in the constructor and then rotated rigidly on each update() call; the number of points per group does not change over time.

• omdi::examples::RotatingPointcloud is declared in examples/pointcloud.h and is included automatically via omdi.hpp.