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dancing_kirby.cpp

A simple example for a delayed_send based application.

A simple example for a delayed_send based application.

// This example illustrates how to do time-triggered loops in CAF.
#include <algorithm>
#include <chrono>
#include <iostream>
#include "caf/all.hpp"
using std::cout;
using std::endl;
using std::pair;
using namespace caf;
// ASCII art figures.
constexpr const char* figures[] = {
"<(^.^<)",
"<(^.^)>",
"(>^.^)>",
};
// Bundes an index to an ASCII art figure plus its position on screen.
struct animation_step {
size_t figure_idx;
size_t offset;
};
// Array of {figure, offset} pairs.
constexpr animation_step animation_steps[] = {
{1, 7}, {0, 7}, {0, 6}, {0, 5}, {1, 5}, {2, 5}, {2, 6},
{2, 7}, {2, 8}, {2, 9}, {2, 10}, {1, 10}, {0, 10}, {0, 9},
{1, 9}, {2, 10}, {2, 11}, {2, 12}, {2, 13}, {1, 13}, {0, 13},
{0, 12}, {0, 11}, {0, 10}, {0, 9}, {0, 8}, {0, 7}, {1, 7},
};
// Width of the printed area.
constexpr size_t animation_width = 20;
// Draws an animation step by printing "{offset_whitespaces}{figure}{padding}".
void draw_kirby(const animation_step& animation) {
cout.width(animation_width);
// Override last figure.
cout << '\r';
// Print left padding (offset).
std::fill_n(std::ostream_iterator<char>{cout}, animation.offset, ' ');
// Print figure.
cout << figures[animation.figure_idx];
// Print right padding.
cout.fill(' ');
// Make sure figure is visible.
cout.flush();
}
// --(rst-dancing-kirby-begin)--
// Uses a message-based loop to iterate over all animation steps.
behavior dancing_kirby(event_based_actor* self) {
// Let's get started.
auto i = std::begin(animation_steps);
auto e = std::end(animation_steps);
self->send(self, update_atom_v);
return {
[=](update_atom) mutable {
// We're done when reaching the past-the-end position.
if (i == e) {
cout << endl;
self->quit();
return;
}
// Print current animation step.
draw_kirby(*i);
// Animate next step in 150ms.
++i;
self->delayed_send(self, std::chrono::milliseconds(150), update_atom_v);
},
};
}
// --(rst-dancing-kirby-end)--
void caf_main(actor_system& system) {
system.spawn(dancing_kirby);
}
CAF_MAIN()
caf::actor_system
Actor environment including scheduler, registry, and optional components such as a middleman.
Definition actor_system.hpp:117
caf::actor_system::spawn
infer_handle_from_class_t< C > spawn(Ts &&... xs)
Returns a new actor of type C using xs... as constructor arguments.
Definition actor_system.hpp:321
caf::behavior
Describes the behavior of an actor, i.e., provides a message handler and an optional timeout.
Definition behavior.hpp:39
caf::event_based_actor
A cooperatively scheduled, event-based actor implementation.
Definition event_based_actor.hpp:53
caf::scheduled_actor::quit
void quit(error x=error{})
Finishes execution of this actor after any currently running message handler is done.
caf
Root namespace of libcaf.
Definition abstract_actor.hpp:44