libinput for keyboard input :3

Signed-off-by: Slendi <slendi@socopon.com>

flake.nix

@@ -34,6 +34,7 @@
           wayland
           zlib
           sdl3
+          libinput
         ];
       in
       {

meson.build

@@ -23,6 +23,8 @@ vulkan_dep = dependency('vulkan')
 openxr_dep = dependency('openxr')
 zlib_dep = dependency('zlib')
 sdl3_dep = dependency('sdl3')
+libinput_dep = dependency('libinput')
+libudev_dep = dependency('libudev')
 imgui_src = files(
 	'thirdparty/imgui/imgui.cpp',
 	'thirdparty/imgui/imgui_draw.cpp',
@@ -140,6 +142,8 @@ exe = executable('vr-compositor',
 		zlib_dep,
 		sdl3_dep,
 		fastgltf_dep,
+		libinput_dep,
+		libudev_dep,
 	],
 	cpp_args: [
 		'--embed-dir=' + join_paths(meson.project_build_root(), 'shaders')

src/Application.cpp

@@ -1,20 +1,204 @@
 #include "Application.h"
 
+#include <algorithm>
+#include <cerrno>
+#include <cstdint>
+#include <fcntl.h>
 #include <iostream>
+#include <optional>
 #include <print>
 #include <stdexcept>
+#include <unistd.h>
 
 #include <SDL3/SDL_events.h>
 #include <SDL3/SDL_init.h>
+#include <SDL3/SDL_mouse.h>
 #include <SDL3/SDL_timer.h>
 #include <SDL3/SDL_video.h>
 
 #include <imgui_impl_sdl3.h>
 #include <imgui_impl_vulkan.h>
 
+#include <libinput.h>
+#include <libudev.h>
+#include <linux/input-event-codes.h>
+
 #include "Util.h"
 #include "VulkanRenderer.h"
 
+namespace {
+
+int open_restricted(char const *path, int flags, void * /*user_data*/)
+{
+	int fd { open(path, flags | O_CLOEXEC) };
+	return fd < 0 ? -errno : fd;
+}
+
+void close_restricted(int fd, void * /*user_data*/) { close(fd); }
+
+libinput_interface const g_libinput_interface {
+	.open_restricted = open_restricted,
+	.close_restricted = close_restricted,
+};
+
+auto linux_key_to_imgui(uint32_t keycode) -> std::optional<ImGuiKey>
+{
+	switch (keycode) {
+	case KEY_ESC:
+		return ImGuiKey_Escape;
+	case KEY_TAB:
+		return ImGuiKey_Tab;
+	case KEY_ENTER:
+		return ImGuiKey_Enter;
+	case KEY_BACKSPACE:
+		return ImGuiKey_Backspace;
+	case KEY_SPACE:
+		return ImGuiKey_Space;
+	case KEY_LEFTSHIFT:
+		return ImGuiKey_LeftShift;
+	case KEY_RIGHTSHIFT:
+		return ImGuiKey_RightShift;
+	case KEY_LEFTCTRL:
+		return ImGuiKey_LeftCtrl;
+	case KEY_RIGHTCTRL:
+		return ImGuiKey_RightCtrl;
+	case KEY_LEFTALT:
+		return ImGuiKey_LeftAlt;
+	case KEY_RIGHTALT:
+		return ImGuiKey_RightAlt;
+	case KEY_LEFTMETA:
+		return ImGuiKey_LeftSuper;
+	case KEY_RIGHTMETA:
+		return ImGuiKey_RightSuper;
+	case KEY_CAPSLOCK:
+		return ImGuiKey_CapsLock;
+	case KEY_NUMLOCK:
+		return ImGuiKey_NumLock;
+	case KEY_SCROLLLOCK:
+		return ImGuiKey_ScrollLock;
+	case KEY_UP:
+		return ImGuiKey_UpArrow;
+	case KEY_DOWN:
+		return ImGuiKey_DownArrow;
+	case KEY_LEFT:
+		return ImGuiKey_LeftArrow;
+	case KEY_RIGHT:
+		return ImGuiKey_RightArrow;
+	case KEY_HOME:
+		return ImGuiKey_Home;
+	case KEY_END:
+		return ImGuiKey_End;
+	case KEY_PAGEUP:
+		return ImGuiKey_PageUp;
+	case KEY_PAGEDOWN:
+		return ImGuiKey_PageDown;
+	case KEY_INSERT:
+		return ImGuiKey_Insert;
+	case KEY_DELETE:
+		return ImGuiKey_Delete;
+	case KEY_F1:
+		return ImGuiKey_F1;
+	case KEY_F2:
+		return ImGuiKey_F2;
+	case KEY_F3:
+		return ImGuiKey_F3;
+	case KEY_F4:
+		return ImGuiKey_F4;
+	case KEY_F5:
+		return ImGuiKey_F5;
+	case KEY_F6:
+		return ImGuiKey_F6;
+	case KEY_F7:
+		return ImGuiKey_F7;
+	case KEY_F8:
+		return ImGuiKey_F8;
+	case KEY_F9:
+		return ImGuiKey_F9;
+	case KEY_F10:
+		return ImGuiKey_F10;
+	case KEY_F11:
+		return ImGuiKey_F11;
+	case KEY_F12:
+		return ImGuiKey_F12;
+	case KEY_0:
+		return ImGuiKey_0;
+	case KEY_1:
+		return ImGuiKey_1;
+	case KEY_2:
+		return ImGuiKey_2;
+	case KEY_3:
+		return ImGuiKey_3;
+	case KEY_4:
+		return ImGuiKey_4;
+	case KEY_5:
+		return ImGuiKey_5;
+	case KEY_6:
+		return ImGuiKey_6;
+	case KEY_7:
+		return ImGuiKey_7;
+	case KEY_8:
+		return ImGuiKey_8;
+	case KEY_9:
+		return ImGuiKey_9;
+	case KEY_A:
+		return ImGuiKey_A;
+	case KEY_B:
+		return ImGuiKey_B;
+	case KEY_C:
+		return ImGuiKey_C;
+	case KEY_D:
+		return ImGuiKey_D;
+	case KEY_E:
+		return ImGuiKey_E;
+	case KEY_F:
+		return ImGuiKey_F;
+	case KEY_G:
+		return ImGuiKey_G;
+	case KEY_H:
+		return ImGuiKey_H;
+	case KEY_I:
+		return ImGuiKey_I;
+	case KEY_J:
+		return ImGuiKey_J;
+	case KEY_K:
+		return ImGuiKey_K;
+	case KEY_L:
+		return ImGuiKey_L;
+	case KEY_M:
+		return ImGuiKey_M;
+	case KEY_N:
+		return ImGuiKey_N;
+	case KEY_O:
+		return ImGuiKey_O;
+	case KEY_P:
+		return ImGuiKey_P;
+	case KEY_Q:
+		return ImGuiKey_Q;
+	case KEY_R:
+		return ImGuiKey_R;
+	case KEY_S:
+		return ImGuiKey_S;
+	case KEY_T:
+		return ImGuiKey_T;
+	case KEY_U:
+		return ImGuiKey_U;
+	case KEY_V:
+		return ImGuiKey_V;
+	case KEY_W:
+		return ImGuiKey_W;
+	case KEY_X:
+		return ImGuiKey_X;
+	case KEY_Y:
+		return ImGuiKey_Y;
+	case KEY_Z:
+		return ImGuiKey_Z;
+	default:
+		return std::nullopt;
+	}
+}
+
+} // namespace
+
 namespace Lunar {
 
 Application::Application()
@@ -33,6 +217,8 @@ Application::Application()
 
 	m_renderer = std::make_unique<VulkanRenderer>(m_window, m_logger);
 
+	init_input();
+
 	mouse_captured(true);
 
 	m_logger.info("App init done!");
@@ -42,6 +228,8 @@ Application::~Application()
 {
 	m_renderer.reset();
 
+	shutdown_input();
+
 	SDL_DestroyWindow(m_window);
 	SDL_Quit();
 
@@ -65,7 +253,10 @@ auto Application::run() -> void
 		if (dt > 0)
 			fps = 1000.0f / (float)dt;
 
+		process_libinput_events();
+
 		while (SDL_PollEvent(&e)) {
+			bool forward_to_imgui { false };
 			if (e.type == SDL_EVENT_QUIT) {
 				m_running = false;
 			} else if (e.type == SDL_EVENT_WINDOW_RESIZED) {
@@ -73,14 +264,25 @@ auto Application::run() -> void
 				SDL_GetWindowSize(m_window, &width, &height);
 				m_renderer->resize(static_cast<uint32_t>(width),
 				    static_cast<uint32_t>(height));
-			} else if (e.type == SDL_EVENT_KEY_DOWN && e.key.repeat == false) {
-				if (e.key.key == SDLK_F11 && e.key.mod & SDL_KMOD_LCTRL) {
-					mouse_captured(!mouse_captured());
-					m_show_imgui = !mouse_captured();
-				}
+				clamp_mouse_to_window(width, height);
+				forward_to_imgui = true;
+			} else if (e.type == SDL_EVENT_MOUSE_MOTION) {
+				m_mouse_x = e.motion.x;
+				m_mouse_y = e.motion.y;
+				forward_to_imgui = true;
+			} else if (e.type == SDL_EVENT_MOUSE_BUTTON_DOWN
+			    || e.type == SDL_EVENT_MOUSE_BUTTON_UP) {
+				m_mouse_x = e.button.x;
+				m_mouse_y = e.button.y;
+				forward_to_imgui = true;
+			} else if (e.type == SDL_EVENT_MOUSE_WHEEL) {
+				m_mouse_x = e.wheel.mouse_x;
+				m_mouse_y = e.wheel.mouse_y;
+				forward_to_imgui = true;
 			}
 
-			ImGui_ImplSDL3_ProcessEvent(&e);
+			if (forward_to_imgui)
+				ImGui_ImplSDL3_ProcessEvent(&e);
 		}
 
 		ImGui_ImplSDL3_NewFrame();
@@ -110,6 +312,111 @@ auto Application::run() -> void
 	}
 }
 
+auto Application::init_input() -> void
+{
+	m_udev = udev_new();
+	if (!m_udev) {
+		m_logger.err("Failed to create udev context");
+		throw std::runtime_error("App init fail");
+	}
+
+	m_libinput
+	    = libinput_udev_create_context(&g_libinput_interface, this, m_udev);
+	if (!m_libinput) {
+		m_logger.err("Failed to create libinput context");
+		shutdown_input();
+		throw std::runtime_error("App init fail");
+	}
+
+	if (libinput_udev_assign_seat(m_libinput, "seat0") != 0) {
+		m_logger.err("Failed to assign libinput seat");
+		shutdown_input();
+		throw std::runtime_error("App init fail");
+	}
+
+	int width {}, height {};
+	SDL_GetWindowSize(m_window, &width, &height);
+	float mouse_x {}, mouse_y {};
+	SDL_GetMouseState(&mouse_x, &mouse_y);
+	m_mouse_x = mouse_x;
+	m_mouse_y = mouse_y;
+	ImGui::GetIO().AddMousePosEvent(
+	    static_cast<float>(m_mouse_x), static_cast<float>(m_mouse_y));
+}
+
+auto Application::shutdown_input() -> void
+{
+	if (m_libinput) {
+		libinput_unref(m_libinput);
+		m_libinput = nullptr;
+	}
+
+	if (m_udev) {
+		udev_unref(m_udev);
+		m_udev = nullptr;
+	}
+}
+
+auto Application::process_libinput_events() -> void
+{
+	if (!m_libinput)
+		return;
+
+	if (int const rc { libinput_dispatch(m_libinput) }; rc != 0) {
+		m_logger.err("libinput_dispatch failed ({})", rc);
+		return;
+	}
+
+	for (libinput_event *event { libinput_get_event(m_libinput) };
+	    event != nullptr; event = libinput_get_event(m_libinput)) {
+		switch (libinput_event_get_type(event)) {
+		case LIBINPUT_EVENT_KEYBOARD_KEY:
+			handle_keyboard_event(libinput_event_get_keyboard_event(event));
+			break;
+		default:
+			break;
+		}
+
+		libinput_event_destroy(event);
+	}
+}
+
+auto Application::handle_keyboard_event(libinput_event_keyboard *event) -> void
+{
+	uint32_t const key { libinput_event_keyboard_get_key(event) };
+	auto const state { libinput_event_keyboard_get_key_state(event) };
+	bool const pressed { state == LIBINPUT_KEY_STATE_PRESSED };
+
+	if (key == KEY_LEFTCTRL || key == KEY_RIGHTCTRL) {
+		if (pressed) {
+			++m_ctrl_pressed_count;
+		} else if (m_ctrl_pressed_count > 0) {
+			--m_ctrl_pressed_count;
+		}
+	}
+
+	if (pressed && key == KEY_F11 && m_ctrl_pressed_count > 0) {
+		mouse_captured(!mouse_captured());
+		m_show_imgui = !mouse_captured();
+	}
+
+	if (auto imgui_key { linux_key_to_imgui(key) }) {
+		ImGui::GetIO().AddKeyEvent(*imgui_key, pressed);
+	}
+}
+
+auto Application::clamp_mouse_to_window(int width, int height) -> void
+{
+	double const max_x { std::max(0.0, static_cast<double>(width - 1)) };
+	double const max_y { std::max(0.0, static_cast<double>(height - 1)) };
+
+	m_mouse_x = std::clamp(m_mouse_x, 0.0, max_x);
+	m_mouse_y = std::clamp(m_mouse_y, 0.0, max_y);
+
+	ImGui::GetIO().AddMousePosEvent(
+	    static_cast<float>(m_mouse_x), static_cast<float>(m_mouse_y));
+}
+
 auto Application::mouse_captured(bool new_state) -> void
 {
 	if (!SDL_SetWindowRelativeMouseMode(m_window, new_state)) {

src/Application.h

@@ -8,6 +8,11 @@
 
 #include <imgui.h>
 
+struct libinput;
+struct libinput_event_keyboard;
+struct libinput_event_pointer;
+struct udev;
+
 namespace Lunar {
 
 struct VulkanRenderer;
@@ -23,13 +28,26 @@ struct Application {
 	auto toggle_mouse_captured() -> void { mouse_captured(!m_mouse_captured); }
 
 private:
+	auto init_input() -> void;
+	auto shutdown_input() -> void;
+	auto process_libinput_events() -> void;
+	auto handle_keyboard_event(libinput_event_keyboard *event) -> void;
+	auto clamp_mouse_to_window(int width, int height) -> void;
+
 	SDL_Window *m_window { nullptr };
 	Logger m_logger { "Lunar" };
 	std::unique_ptr<VulkanRenderer> m_renderer;
 
+	udev *m_udev { nullptr };
+	libinput *m_libinput { nullptr };
+
 	bool m_running { true };
 	bool m_mouse_captured { false };
 	bool m_show_imgui { false };
+	int m_ctrl_pressed_count { 0 };
+
+	double m_mouse_x { 0.0 };
+	double m_mouse_y { 0.0 };
 };
 
 } // namespace Lunar