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shm.cpp

This is an example of how to use the Wayland C++ bindings with SHM.

/*
* Copyright (c) 2014-2022, Nils Christopher Brause, Philipp Kerling, Zsolt Bölöny
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <stdexcept>
#include <iostream>
#include <array>
#include <memory>
#include <sstream>
#include <ctime>
#include <algorithm>
#include <random>
#include <cstdint>
#include <wayland-client.hpp>
#include <wayland-client-protocol-extra.hpp>
#include <linux/input.h>
#include <wayland-cursor.hpp>
#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
using namespace wayland;
// helper to create a std::function out of a member function and an object
template <typename R, typename T, typename... Args>
std::function<R(Args...)> bind_mem_fn(R(T::* func)(Args...), T *t)
{
return [func, t] (Args... args)
{
return (t->*func)(args...);
};
}
// shared memory helper class
class shared_mem_t
{
private:
std::string name;
int fd = 0;
size_t len = 0;
void *mem = nullptr;
public:
shared_mem_t() = default;
shared_mem_t(const shared_mem_t&) = delete;
shared_mem_t(shared_mem_t&&) noexcept = delete;
shared_mem_t& operator=(const shared_mem_t&) = delete;
shared_mem_t& operator=(shared_mem_t&&) noexcept = delete;
shared_mem_t(size_t size)
: len(size)
{
// create random filename
std::stringstream ss;
std::random_device device;
std::default_random_engine engine(device());
std::uniform_int_distribution<unsigned int> distribution(0, std::numeric_limits<unsigned int>::max());
ss << distribution(engine);
name = ss.str();
// open shared memory file
fd = memfd_create(name.c_str(), 0);
if(fd < 0)
throw std::runtime_error("shm_open failed.");
// set size
if(ftruncate(fd, size) < 0)
throw std::runtime_error("ftruncate failed.");
// map memory
mem = mmap(nullptr, len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if(mem == MAP_FAILED) // NOLINT
throw std::runtime_error("mmap failed.");
}
~shared_mem_t() noexcept
{
if(fd)
{
if(munmap(mem, len) < 0)
std::cerr << "munmap failed.";
if(close(fd) < 0)
std::cerr << "close failed.";
if(shm_unlink(name.c_str()) < 0)
std::cerr << "shm_unlink failed";
}
}
int get_fd() const
{
return fd;
}
void *get_mem()
{
return mem;
}
};
// example Wayland client
class example
{
private:
// global objects
display_t display;
registry_t registry;
compositor_t compositor;
shell_t shell;
xdg_wm_base_t xdg_wm_base;
seat_t seat;
shm_t shm;
// local objects
surface_t surface;
shell_surface_t shell_surface;
xdg_surface_t xdg_surface;
xdg_toplevel_t xdg_toplevel;
pointer_t pointer;
keyboard_t keyboard;
callback_t frame_cb;
cursor_image_t cursor_image;
buffer_t cursor_buffer;
surface_t cursor_surface;
std::shared_ptr<shared_mem_t> shared_mem;
std::array<buffer_t, 2> buffer;
int cur_buf;
bool running;
bool has_pointer;
bool has_keyboard;
void draw(uint32_t serial = 0)
{
float h = static_cast<float>((serial >> 4) & 0xFF)/255.0F;
float s = 1;
float v = 1;
int hi = static_cast<int>(h*6);
float f = h*6 - static_cast<float>(hi);
float p = v*(1-s);
float q = v*(1-s*f);
float t = v*(1-s*(1-f));
float r = 0;
float g = 0;
float b = 0;
switch(hi)
{
case 1:
r = q; g = v; b = p;
break;
case 2:
r = p; g = v; b = t;
break;
case 3:
r = p; g = q; b = v;
break;
case 4:
r = t; g = p; b = v;
break;
case 5:
r = v; g = p; b = q;
break;
default: // 0,6
r = v; g = t; b = p;
break;
}
// draw stuff
uint32_t pixel = (0x80 << 24)
| (static_cast<uint32_t>(r * 255.0) << 16)
| (static_cast<uint32_t>(g * 255.0) << 8)
| static_cast<uint32_t>(b * 255.0);
std::fill_n(static_cast<uint32_t*>(shared_mem->get_mem())+cur_buf*320*240, 320*240, pixel);
surface.attach(buffer.at(cur_buf), 0, 0);
surface.damage(0, 0, 320, 240);
if(!cur_buf)
cur_buf = 1;
else
cur_buf = 0;
// schedule next draw
frame_cb = surface.frame();
frame_cb.on_done() = bind_mem_fn(&example::draw, this);
surface.commit();
}
public:
example(const example&) = delete;
example(example&&) noexcept = delete;
~example() noexcept = default;
example& operator=(const example&) = delete;
example& operator=(example&&) noexcept = delete;
example()
{
// retrieve global objects
registry = display.get_registry();
registry.on_global() = [&] (uint32_t name, const std::string& interface, uint32_t version)
{
if(interface == compositor_t::interface_name)
registry.bind(name, compositor, version);
else if(interface == shell_t::interface_name)
registry.bind(name, shell, version);
else if(interface == xdg_wm_base_t::interface_name)
registry.bind(name, xdg_wm_base, version);
else if(interface == seat_t::interface_name)
registry.bind(name, seat, version);
else if(interface == shm_t::interface_name)
registry.bind(name, shm, version);
};
display.roundtrip();
seat.on_capabilities() = [&] (const seat_capability& capability)
{
has_keyboard = capability & seat_capability::keyboard;
has_pointer = capability & seat_capability::pointer;
};
// create a surface
surface = compositor.create_surface();
// create a shell surface
if(xdg_wm_base)
{
xdg_wm_base.on_ping() = [&] (uint32_t serial) { xdg_wm_base.pong(serial); };
xdg_surface = xdg_wm_base.get_xdg_surface(surface);
xdg_surface.on_configure() = [&] (uint32_t serial) { xdg_surface.ack_configure(serial); };
xdg_toplevel = xdg_surface.get_toplevel();
xdg_toplevel.set_title("Window");
xdg_toplevel.on_close() = [&] () { running = false; };
}
else
{
shell_surface = shell.get_shell_surface(surface);
shell_surface.on_ping() = [&] (uint32_t serial) { shell_surface.pong(serial); };
shell_surface.set_title("Window");
shell_surface.set_toplevel();
}
surface.commit();
display.roundtrip();
// Get input devices
if(!has_keyboard)
throw std::runtime_error("No keyboard found.");
if(!has_pointer)
throw std::runtime_error("No pointer found.");
pointer = seat.get_pointer();
keyboard = seat.get_keyboard();
// create shared memory
shared_mem = std::make_shared<shared_mem_t>(2*320*240*4);
auto pool = shm.create_pool(shared_mem->get_fd(), 2*320*240*4);
for(unsigned int c = 0; c < 2; c++)
buffer.at(c) = pool.create_buffer(c*320*240*4, 320, 240, 320*4, shm_format::argb8888);
cur_buf = 0;
// load cursor theme
cursor_theme_t cursor_theme = cursor_theme_t("default", 16, shm);
cursor_t cursor = cursor_theme.get_cursor("cross");
cursor_image = cursor.image(0);
cursor_buffer = cursor_image.get_buffer();
// create cursor surface
cursor_surface = compositor.create_surface();
// draw cursor
pointer.on_enter() = [&] (uint32_t serial, const surface_t& /*unused*/, int32_t /*unused*/, int32_t /*unused*/)
{
cursor_surface.attach(cursor_buffer, 0, 0);
cursor_surface.damage(0, 0, cursor_image.width(), cursor_image.height());
cursor_surface.commit();
pointer.set_cursor(serial, cursor_surface, 0, 0);
};
// window movement
pointer.on_button() = [&] (uint32_t serial, uint32_t /*unused*/, uint32_t button, pointer_button_state state)
{
if(button == BTN_LEFT && state == pointer_button_state::pressed)
{
if(xdg_toplevel)
xdg_toplevel.move(seat, serial);
else
shell_surface.move(seat, serial);
}
};
// press 'q' to exit
keyboard.on_key() = [&] (uint32_t /*unused*/, uint32_t /*unused*/, uint32_t key, keyboard_key_state state)
{
if(key == KEY_Q && state == keyboard_key_state::pressed)
running = false;
};
// draw stuff
draw();
}
void run()
{
// event loop
running = true;
while(running)
display.dispatch();
}
};
int main()
{
example e;
e.run();
return 0;
}
wayland-client.hpp