move app code to new module

Mostly to keep it clean.

README.md

@@ -1,14 +1,15 @@
 # retrovnc
 
-a headless Libretro frontend that exports a VNC server.
+A fully headless Libretro frontend that exports a VNC server for display and input.
 
-This is mostly a "fun project", and probably isn't a very great solution for remote gaming. 
+In layman terms, this lets you play games over VNC. Which isn't all that great, but hey.
+
+This is mostly a "fun project" and consists mostly of code I already wrote.
 
 # Dependencies
 
 - A C++ toolchain
-- A Rust toolchain. 
-- Maybe libvncserver (i'm not sure, it seems like the package can build it).
+- A Rust toolchain.
 
 # Building
 
@@ -16,8 +17,9 @@ This is mostly a "fun project", and probably isn't a very great solution for rem
 
 # Usage
 
-`$ retrovnc --core <CORE> --rom <ROM>`
+`$ retrovnc --core <CORE> --rom <ROM>` (see `retrovnc --help` for more options)
 
 For disc-based titles it is probably a good idea to pass the cuesheet file. I will implement stuff later to make this less annoying.
 
 
+

crates/retro_frontend/src/frontend.rs

@@ -68,6 +68,7 @@ pub struct Frontend {
 	pub(crate) game_loaded: bool,
 
 	pub(crate) av_info: Option<SystemAvInfo>,
+	pub(crate) sys_info: Option<SystemInfo>,
 
 	/// The core's requested pixel format.
 	/// TODO: HW accel. (or just not care)
@@ -114,6 +115,7 @@ impl Frontend {
 			game_loaded: false,
 
 			av_info: None,
+			sys_info: None,
 
 			pixel_format: PixelFormat::RGB565,
 			converted_pixel_buffer: Vec::new(),
@@ -327,13 +329,6 @@ impl Frontend {
 			);
 
 			info!("Core {} loaded", path.as_ref().display());
-
-			// Get AV info
-			// Like core API, we have to MaybeUninit again.
-			let mut av_info: MaybeUninit<SystemAvInfo> = MaybeUninit::uninit();
-			(core_api_ref.retro_get_system_av_info)(av_info.as_mut_ptr());
-
-			self.av_info = Some(av_info.assume_init());
 		}
 
 		Ok(())
@@ -381,32 +376,46 @@ impl Frontend {
 			return Err(Error::CoreNotLoaded);
 		}
 
-		// For now I'm only implementing the gameinfo garbage that
-		// makes you read the whole file in. Later on I'll look into VFS
-		// support; but for now, it seems more cores will probably
-		// play ball with this.. which sucks :(
-
 		// I'm aware this is nasty but bleh
 		let slice = path.as_ref().as_os_str().as_bytes();
 		let path_string = CString::new(slice).expect("shouldn't fail");
-		let contents = fs::read(path)?;
 
-		let gameinfo = GameInfo {
-			path: path_string.as_ptr(),
-			data: contents.as_ptr() as *const ffi::c_void,
-			size: contents.len(),
-			meta: std::ptr::null(),
-		};
+		let system_info = self.get_system_info()?;
 
 		let core_api = self.core_api.as_ref().unwrap();
 
-		unsafe {
-			if !(core_api.retro_load_game)(&gameinfo) {
-				return Err(Error::RomLoadFailed);
-			}
+		let mut gameinfo = GameInfo {
+			path: path_string.as_ptr(),
+			data: std::ptr::null(),
+			size: 0,
+			meta: std::ptr::null(),
+		};
 
-			self.game_loaded = true;
-			Ok(())
+		// If the core does not need fullpath, then
+		// read the file data into a buffer we give to the core.
+		// This is pretty wasteful but works.
+		if !system_info.need_fullpath {
+			let contents = fs::read(path)?;
+			gameinfo.data = contents.as_ptr() as *const ffi::c_void;
+			gameinfo.size = contents.len();
+
+			unsafe {
+				if !(core_api.retro_load_game)(&gameinfo) {
+					return Err(Error::RomLoadFailed);
+				}
+
+				self.game_loaded = true;
+				Ok(())
+			}
+		} else {
+			unsafe {
+				if !(core_api.retro_load_game)(&gameinfo) {
+					return Err(Error::RomLoadFailed);
+				}
+
+				self.game_loaded = true;
+				Ok(())
+			}
 		}
 	}
 
@@ -436,7 +445,39 @@ impl Frontend {
 		if let Some(av) = self.av_info.as_ref() {
 			Ok(av.clone())
 		} else {
-			Err(Error::NoAvInfo)
+			// Get AV info
+			// Like core API, we have to MaybeUninit again.
+			let mut av_info: MaybeUninit<SystemAvInfo> = MaybeUninit::uninit();
+			unsafe {
+				let core_api = self.core_api.as_ref().unwrap();
+				(core_api.retro_get_system_av_info)(av_info.as_mut_ptr());
+
+				self.av_info = Some(av_info.assume_init());
+			}
+
+			Ok(self.av_info.as_ref().unwrap().clone())
+		}
+	}
+
+	pub fn get_system_info(&mut self) -> Result<SystemInfo> {
+		if !self.core_loaded() {
+			return Err(Error::CoreNotLoaded);
+		}
+
+		if let Some(sys) = self.sys_info.as_ref() {
+			Ok(sys.clone())
+		} else {
+			let mut sys_info: MaybeUninit<SystemInfo> = MaybeUninit::uninit();
+
+			// Actually get the system info
+			unsafe {
+				let core_api = self.core_api.as_ref().unwrap();
+				(core_api.retro_get_system_info)(sys_info.as_mut_ptr());
+
+				self.sys_info = Some(sys_info.assume_init());
+			}
+
+			Ok(self.sys_info.as_ref().unwrap().clone())
 		}
 	}
 

crates/retro_frontend/src/libretro_callbacks.rs

@@ -6,7 +6,7 @@ use rgb565::Rgb565;
 
 use std::ffi;
 
-use tracing::{debug, error, info};
+use tracing::{debug, error};
 
 /// This function is used with HW OpenGL cores to transfer the current FBO's ID.
 unsafe extern "C" fn hw_gl_get_framebuffer() -> usize {
@@ -110,7 +110,9 @@ pub(crate) unsafe extern "C" fn environment_callback(
 			let hw_render_context_type =
 				HwContextType::from_uint(hw_render.context_type).expect("Uh oh!");
 
-			if hw_render_context_type != HwContextType::OpenGL && hw_render_context_type != HwContextType::OpenGLCore {
+			if hw_render_context_type != HwContextType::OpenGL
+				&& hw_render_context_type != HwContextType::OpenGLCore
+			{
 				error!(
 					"Core is trying to request an context type we don't support ({:?}), failing",
 					hw_render_context_type
@@ -118,8 +120,6 @@ pub(crate) unsafe extern "C" fn environment_callback(
 				return false;
 			}
 
-			info!("Core requesting context type {:?}", hw_render_context_type);
-
 			let init_data = (*(*FRONTEND).interface).hw_gl_init();
 
 			hw_render.get_current_framebuffer = hw_gl_get_framebuffer;
@@ -239,9 +239,8 @@ pub(crate) unsafe extern "C" fn video_refresh_callback(
 				(pitch * height as usize) as usize,
 			);
 
-			// Resize the pixel buffer if we need to
+			// Resize the conversion buffer if we need to
 			if (pitch * height as usize) as usize != (*FRONTEND).converted_pixel_buffer.len() {
-				info!("Resizing RGB565 -> RGBA buffer");
 				(*FRONTEND)
 					.converted_pixel_buffer
 					.resize((pitch * height as usize) as usize, 0);

crates/retrovnc/src/app.rs

@@ -0,0 +1,394 @@
+use crate::egl;
+use crate::rfb::*;
+
+use std::{path::Path, time::Duration};
+
+use retro_frontend::{
+	frontend::{Frontend, FrontendInterface, HwGlInitData},
+	input_devices::{InputDevice, RetroPad},
+};
+
+use anyhow::Result;
+
+/// Called by OpenGL. We use this to dump errors.
+extern "system" fn opengl_message_callback(
+	source: gl::types::GLenum,
+	_type: gl::types::GLenum,
+	id: gl::types::GLuint,
+	_severity: gl::types::GLenum,
+	_length: gl::types::GLsizei,
+	message: *const gl::types::GLchar,
+	_user: *mut std::ffi::c_void,
+) {
+	unsafe {
+		let message = std::ffi::CStr::from_ptr(message);
+		if _type == gl::DEBUG_TYPE_ERROR {
+			tracing::error!(
+				"OpenGL error: {:?} (res {:08x}, id = {:08x}, source = {:08x})",
+				message,
+				_type,
+				id,
+				source
+			);
+		}
+	}
+}
+
+pub struct App {
+	/// The frontend.
+	frontend: Option<Box<Frontend>>,
+
+	/// VNC server
+	rfb_server: Box<RfbServer>,
+
+	pad: RetroPad,
+
+	/// True if HW rendering is active.
+	hw_render: bool,
+
+	// EGL state
+	egl_display: egl::types::EGLDisplay,
+	egl_context: egl::types::EGLContext,
+
+	// OpenGL object IDs
+	texture_id: gl::types::GLuint,
+	renderbuffer_id: gl::types::GLuint,
+	fbo_id: gl::types::GLuint,
+
+	/// Cached readback buffer.
+	readback_buffer: Vec<u32>,
+}
+
+impl App {
+	pub fn new(rfb_config: RfbServerConfig) -> Result<Box<Self>> {
+		let mut boxed = Box::new(Self {
+			frontend: None,
+			rfb_server: RfbServer::new(rfb_config)?,
+			pad: RetroPad::new(),
+			hw_render: false,
+			egl_display: std::ptr::null(),
+			egl_context: std::ptr::null(),
+			texture_id: 0,
+			renderbuffer_id: 0,
+			fbo_id: 0,
+			readback_buffer: Vec::new(),
+		});
+
+		// SAFETY: The boxed allocation will never drop since the main loop always loops forever.
+		// Even if it did, the only way to touch the pointer involves the frontend library calling retro_run,
+		// and the core calling one of the given callbacks. Therefore this is gnarly, but "fine".
+		//
+		// I'm still not really sure how to tell the borrow checker that this is alright,
+		// short of Box::leak() (which I don't want to do, since ideally I'd like actual cleanup to occur).
+		let obj = &mut *boxed as &mut dyn FrontendInterface;
+		boxed.frontend = Some(Frontend::new(obj as *mut dyn FrontendInterface));
+
+		Ok(boxed)
+	}
+
+	fn get_frontend(&mut self) -> &mut Frontend {
+		self.frontend.as_mut().unwrap()
+	}
+
+	pub fn init(&mut self) {
+		// Currently retrovnc just hardcodes the assumption of a single RetroPad.
+
+		// SAFETY: This too won't ever be Use-After-Free'd because the only oppoturnity to
+		// goes away on drop as well. That's a bit flaky reasoning wise, but is true.
+		//
+		// In all honesty, I'm not sure this even needs to be a *mut so I could see if
+		// making it a immutable reference works.
+		let pad = &mut self.pad as *mut dyn InputDevice;
+		self.get_frontend().plug_input_device(0, pad);
+
+		// Initalize the display
+		self.init_display();
+	}
+
+	fn init_display(&mut self) {
+		let av_info = self.get_frontend().get_av_info().expect("No AV info");
+
+		// Start VNC server.
+		{
+			let server = &mut self.rfb_server;
+			tracing::info!("Starting VNC server");
+			server.start();
+			server.resize(
+				av_info.geometry.base_width as u16,
+				av_info.geometry.base_height as u16,
+			);
+		}
+	}
+
+	pub fn load_core<P: AsRef<Path>>(&mut self, path: P) -> Result<()> {
+		// Unload an existing core.
+		if self.get_frontend().core_loaded() {
+			let _ = self.get_frontend().unload_core();
+		}
+
+		self.get_frontend().load_core(path)?;
+		Ok(())
+	}
+
+	pub fn load_game<P: AsRef<Path>>(&mut self, path: P) -> Result<()> {
+		self.get_frontend().load_game(path)?;
+		Ok(())
+	}
+
+	/// Initalizes a headless EGL context for OpenGL rendering.
+	unsafe fn hw_gl_egl_init(&mut self) {
+		self.egl_display = egl::get_device_platform_display();
+
+		self.egl_context = {
+			const EGL_CONFIG_ATTRIBUTES: [egl::types::EGLenum; 13] = [
+				egl::SURFACE_TYPE,
+				egl::PBUFFER_BIT,
+				egl::BLUE_SIZE,
+				8,
+				egl::RED_SIZE,
+				8,
+				egl::BLUE_SIZE,
+				8,
+				egl::DEPTH_SIZE,
+				8,
+				egl::RENDERABLE_TYPE,
+				egl::OPENGL_BIT,
+				egl::NONE,
+			];
+			let mut egl_major: egl::EGLint = 0;
+			let mut egl_minor: egl::EGLint = 0;
+
+			let mut egl_config_count: egl::EGLint = 0;
+
+			let mut config: egl::types::EGLConfig = std::ptr::null();
+
+			egl::Initialize(
+				self.egl_display,
+				std::ptr::addr_of_mut!(egl_major),
+				std::ptr::addr_of_mut!(egl_minor),
+			);
+
+			egl::ChooseConfig(
+				self.egl_display,
+				EGL_CONFIG_ATTRIBUTES.as_ptr() as *const egl::EGLint,
+				std::ptr::addr_of_mut!(config),
+				1,
+				std::ptr::addr_of_mut!(egl_config_count),
+			);
+
+			egl::BindAPI(egl::OPENGL_API);
+
+			let context =
+				egl::CreateContext(self.egl_display, config, egl::NO_CONTEXT, std::ptr::null());
+
+			// Make the context current on the display so OpenGL routines "just work"
+			egl::MakeCurrent(self.egl_display, egl::NO_SURFACE, egl::NO_SURFACE, context);
+
+			context
+		};
+	}
+
+	/// Destroys EGL resources.
+	unsafe fn hw_gl_egl_exit(&mut self) {
+		if self.hw_render {
+			// Delete FBO
+			self.hw_gl_delete_fbo();
+
+			// Release the EGL context we created before destroying it
+			egl::MakeCurrent(
+				self.egl_display,
+				egl::NO_SURFACE,
+				egl::NO_SURFACE,
+				egl::NO_CONTEXT,
+			);
+			egl::DestroyContext(self.egl_display, self.egl_context);
+			egl::Terminate(self.egl_display);
+			self.egl_display = std::ptr::null();
+			self.egl_context = std::ptr::null();
+		}
+	}
+
+	/// Deletes all OpenGL FBO resources (the FBO itself, the render texture, and the renderbuffer used for depth)
+	fn hw_gl_delete_fbo(&mut self) {
+		unsafe {
+			gl::DeleteFramebuffers(1, std::ptr::addr_of_mut!(self.fbo_id));
+			self.fbo_id = 0;
+
+			gl::DeleteTextures(1, std::ptr::addr_of_mut!(self.texture_id));
+			self.texture_id = 0;
+
+			gl::DeleteRenderbuffers(1, std::ptr::addr_of_mut!(self.renderbuffer_id));
+			self.renderbuffer_id = 0;
+		}
+	}
+
+	fn hw_gl_create_fbo(&mut self, width: u32, height: u32) {
+		unsafe {
+			if self.fbo_id != 0 {
+				self.hw_gl_delete_fbo();
+			}
+
+			gl::GenFramebuffers(1, std::ptr::addr_of_mut!(self.fbo_id));
+			gl::BindFramebuffer(gl::FRAMEBUFFER, self.fbo_id);
+
+			gl::GenTextures(1, std::ptr::addr_of_mut!(self.texture_id));
+			gl::BindTexture(gl::TEXTURE_2D, self.texture_id);
+
+			gl::TexImage2D(
+				gl::TEXTURE_2D,
+				0,
+				gl::RGBA8 as i32,
+				width as i32,
+				height as i32,
+				0,
+				gl::RGBA,
+				gl::UNSIGNED_BYTE,
+				std::ptr::null(),
+			);
+
+			gl::GenRenderbuffers(1, std::ptr::addr_of_mut!(self.renderbuffer_id));
+			gl::BindRenderbuffer(gl::RENDERBUFFER, self.renderbuffer_id);
+
+			gl::RenderbufferStorage(
+				gl::RENDERBUFFER,
+				gl::DEPTH_COMPONENT,
+				width as i32,
+				height as i32,
+			);
+
+			gl::FramebufferTexture2D(
+				gl::FRAMEBUFFER,
+				gl::COLOR_ATTACHMENT0,
+				gl::TEXTURE_2D,
+				self.texture_id,
+				0,
+			);
+
+			gl::BindTexture(gl::TEXTURE_2D, 0);
+
+			gl::FramebufferRenderbuffer(
+				gl::FRAMEBUFFER,
+				gl::DEPTH_ATTACHMENT,
+				gl::RENDERBUFFER,
+				self.renderbuffer_id,
+			);
+
+			gl::BindRenderbuffer(gl::RENDERBUFFER, 0);
+
+			gl::Viewport(0, 0, width as i32, height as i32);
+
+			gl::BindFramebuffer(gl::FRAMEBUFFER, 0);
+
+			// Notify the frontend layer about the new FBO
+			let id = self.fbo_id;
+			self.get_frontend().set_gl_fbo(id);
+
+			// Resize the readback buffer
+			self.readback_buffer.resize((width * height) as usize, 0);
+		}
+	}
+
+	/// The main loop. Should probably be abstracted a bit better.
+	pub fn main_loop(&mut self) -> ! {
+		let frontend = self.get_frontend();
+
+		let av_info = frontend.get_av_info().expect("???");
+		let step_ms = (1.0 / av_info.timing.fps) * 1000.;
+		let step_duration = Duration::from_micros((step_ms * 1000.) as u64);
+
+		// Do the main loop
+		loop {
+			frontend.run_frame();
+			std::thread::sleep(step_duration);
+		}
+	}
+}
+
+impl FrontendInterface for App {
+	fn video_resize(&mut self, width: u32, height: u32) {
+		tracing::info!("Resized to {width}x{height}");
+
+		// Resize OpenGL resources if we need to.
+		if self.hw_render {
+			self.hw_gl_create_fbo(width, height);
+		}
+
+		self.rfb_server.resize(width as u16, height as u16);
+	}
+
+	fn video_update(&mut self, slice: &[u32], pitch: u32) {
+		//let framebuffer_size = self.get_frontend().get_size();
+		self.rfb_server.update_buffer(&slice, pitch, false);
+	}
+
+	fn video_update_gl(&mut self) {
+		let dimensions = self.get_frontend().get_size();
+
+		unsafe {
+			gl::BindFramebuffer(gl::FRAMEBUFFER, self.fbo_id);
+
+			// I know this sucks but it works for this case.
+			gl::ReadPixels(
+				0,
+				0,
+				dimensions.0 as i32,
+				dimensions.1 as i32,
+				gl::RGBA,
+				gl::UNSIGNED_BYTE,
+				self.readback_buffer.as_mut_ptr() as *mut std::ffi::c_void,
+			);
+
+			self.rfb_server
+				.update_buffer(&self.readback_buffer[..], dimensions.0, true);
+
+			gl::BindFramebuffer(gl::FRAMEBUFFER, 0);
+		}
+	}
+
+	fn audio_sample(&mut self, _slice: &[i16], _size: usize) {}
+
+	fn input_poll(&mut self) {
+		self.pad.reset();
+
+		// Press all buttons the VNC server marked as pressed
+		let buttons = self.rfb_server.get_buttons();
+		for i in 0..buttons.len() {
+			if buttons[i] {
+				self.pad.press_button(i as u32, None);
+			}
+		}
+	}
+
+	fn hw_gl_init(&mut self) -> HwGlInitData {
+		if self.hw_render {
+			panic!("Cannot initalize HW rendering more than once");
+		}
+
+		unsafe {
+			// Initalize EGL
+			self.hw_gl_egl_init();
+
+			// load OpenGL functions (using EGL loader. We should probably check the one extension exists)
+			gl::load_with(|s| {
+				let str = std::ffi::CString::new(s).expect("Uhh huh.");
+				std::mem::transmute(egl::GetProcAddress(str.as_ptr()))
+			});
+
+			// set OpenGL debug message callback
+			gl::Enable(gl::DEBUG_OUTPUT);
+			gl::DebugMessageCallback(Some(opengl_message_callback), std::ptr::null());
+
+			// Create the initial FBO for the core to render to
+			let dimensions = self.get_frontend().get_size();
+			self.hw_gl_create_fbo(dimensions.0, dimensions.1);
+		}
+
+		self.hw_render = true;
+
+		return unsafe {
+			HwGlInitData {
+				get_proc_address: std::mem::transmute(egl::GetProcAddress as *mut std::ffi::c_void),
+			}
+		};
+	}
+}

crates/retrovnc/src/egl.rs

@@ -1,3 +1,5 @@
+//! EGL bindings and helpers.
+
 #[allow(non_camel_case_types)]
 #[allow(unused_imports)]
 mod egl_impl {
@@ -15,6 +17,8 @@ mod egl_impl {
 
 	include!(concat!(env!("OUT_DIR"), "/egl_bindings.rs"));
 
+	// TODO: Move these helpers to a new "helpers" module.
+
 	pub type GetPlatformDisplayExt = unsafe extern "C" fn(
 		platform: types::EGLenum,
 		native_display: *const std::ffi::c_void,

crates/retrovnc/src/main.rs

@@ -1,382 +1,18 @@
-use std::{net::Ipv4Addr, path::Path, time::Duration};
-
 use anyhow::Result;
+use std::net::Ipv4Addr;
 
-use retro_frontend::{
-	frontend::{Frontend, FrontendInterface, HwGlInitData},
-	input_devices::{InputDevice, RetroPad},
-};
 use tracing::Level;
 use tracing_subscriber::FmtSubscriber;
 
 use clap::{arg, command, value_parser};
 
-/// Called by OpenGL. We use this to dump errors.
-extern "system" fn opengl_message_callback(
-	source: gl::types::GLenum,
-	_type: gl::types::GLenum,
-	id: gl::types::GLuint,
-	_severity: gl::types::GLenum,
-	_length: gl::types::GLsizei,
-	message: *const gl::types::GLchar,
-	_user: *mut std::ffi::c_void,
-) {
-	unsafe {
-		let message = std::ffi::CStr::from_ptr(message);
-		if _type == gl::DEBUG_TYPE_ERROR {
-			tracing::error!(
-				"OpenGL error: {:?} (res {:08x}, id = {:08x}, source = {:08x})",
-				message,
-				_type,
-				id,
-				source
-			);
-		}
-	}
-}
+mod app;
 
 mod egl;
 mod rfb;
-use rfb::*;
 
-struct App {
-	frontend: Option<Box<Frontend>>,
-	rfb_server: Box<RfbServer>,
-	pad: RetroPad,
-
-	hw_render: bool,
-
-	// EGL state
-	egl_display: egl::types::EGLDisplay,
-	egl_context: egl::types::EGLContext,
-
-	// OpenGL object IDs
-	texture_id: gl::types::GLuint,
-	renderbuffer_id: gl::types::GLuint,
-	fbo_id: gl::types::GLuint,
-
-	/// Cached readback buffer.
-	readback_buffer: Vec<u32>,
-}
-
-impl App {
-	fn new(rfb_config: RfbServerConfig) -> Result<Box<Self>> {
-		let mut boxed = Box::new(Self {
-			frontend: None,
-			rfb_server: RfbServer::new(rfb_config)?,
-			pad: RetroPad::new(),
-			hw_render: false,
-			egl_display: std::ptr::null(),
-			egl_context: std::ptr::null(),
-			texture_id: 0,
-			renderbuffer_id: 0,
-			fbo_id: 0,
-			readback_buffer: Vec::new(),
-		});
-
-		// Very very nasty, but honestly it works.
-		// I'll look into cleaning it up later.
-		let obj = &mut *boxed as &mut dyn FrontendInterface;
-		boxed.frontend = Some(Frontend::new(obj as *mut dyn FrontendInterface));
-
-		Ok(boxed)
-	}
-
-	fn get_frontend(&mut self) -> &mut Frontend {
-		self.frontend.as_mut().unwrap()
-	}
-
-	fn init(&mut self) {
-		// Currently retrovnc just hardcodes the assumption of a single RetroPad.
-		let pad = &mut self.pad as *mut dyn InputDevice;
-
-		self.get_frontend().plug_input_device(0, pad);
-
-		// Initalize the display
-		self.init_display();
-	}
-
-	fn init_display(&mut self) {
-		let av_info = self.get_frontend().get_av_info().expect("No AV info");
-
-		// Start VNC server.
-		{
-			let server = &mut self.rfb_server;
-			tracing::info!("Starting VNC server");
-			server.start();
-			server.resize(
-				av_info.geometry.base_width as u16,
-				av_info.geometry.base_height as u16,
-			);
-		}
-	}
-
-	fn load_core<P: AsRef<Path>>(&mut self, path: P) -> Result<()> {
-		if self.get_frontend().core_loaded() {
-			println!("???");
-			let _ = self.get_frontend().unload_core();
-		}
-
-		self.get_frontend().load_core(path)?;
-		Ok(())
-	}
-
-	fn load_game<P: AsRef<Path>>(&mut self, path: P) -> Result<()> {
-		self.get_frontend().load_game(path)?;
-		Ok(())
-	}
-
-	/// Initalizes a headless EGL context for OpenGL rendering.
-	unsafe fn hw_gl_egl_init(&mut self) {
-		self.egl_display = egl::get_device_platform_display();
-
-		self.egl_context = {
-			const EGL_CONFIG_ATTRIBUTES: [egl::types::EGLenum; 13] = [
-				egl::SURFACE_TYPE,
-				egl::PBUFFER_BIT,
-				egl::BLUE_SIZE,
-				8,
-				egl::RED_SIZE,
-				8,
-				egl::BLUE_SIZE,
-				8,
-				egl::DEPTH_SIZE,
-				8,
-				egl::RENDERABLE_TYPE,
-				egl::OPENGL_BIT,
-				egl::NONE,
-			];
-			let mut egl_major: egl::EGLint = 0;
-			let mut egl_minor: egl::EGLint = 0;
-
-			let mut egl_config_count: egl::EGLint = 0;
-
-			let mut config: egl::types::EGLConfig = std::ptr::null();
-
-			egl::Initialize(
-				self.egl_display,
-				std::ptr::addr_of_mut!(egl_major),
-				std::ptr::addr_of_mut!(egl_minor),
-			);
-
-			egl::ChooseConfig(
-				self.egl_display,
-				EGL_CONFIG_ATTRIBUTES.as_ptr() as *const egl::EGLint,
-				std::ptr::addr_of_mut!(config),
-				1,
-				std::ptr::addr_of_mut!(egl_config_count),
-			);
-
-			egl::BindAPI(egl::OPENGL_API);
-
-			let context =
-				egl::CreateContext(self.egl_display, config, egl::NO_CONTEXT, std::ptr::null());
-
-			// Make the context current on the display so OpenGL routines "just work"
-			egl::MakeCurrent(self.egl_display, egl::NO_SURFACE, egl::NO_SURFACE, context);
-
-			context
-		};
-	}
-
-	/// Destroys EGL resources.
-	unsafe fn hw_gl_egl_exit(&mut self) {
-		// Release the EGL context we created before destroying it
-		egl::MakeCurrent(
-			self.egl_display,
-			egl::NO_SURFACE,
-			egl::NO_SURFACE,
-			egl::NO_CONTEXT,
-		);
-		egl::DestroyContext(self.egl_display, self.egl_context);
-		egl::Terminate(self.egl_display);
-		self.egl_display = std::ptr::null();
-		self.egl_context = std::ptr::null();
-	}
-
-	fn hw_gl_delete_fbo(&mut self) {
-		unsafe {
-			gl::DeleteFramebuffers(1, std::ptr::addr_of_mut!(self.fbo_id));
-			self.fbo_id = 0;
-
-			gl::DeleteTextures(1, std::ptr::addr_of_mut!(self.texture_id));
-			self.texture_id = 0;
-
-			gl::DeleteRenderbuffers(1, std::ptr::addr_of_mut!(self.renderbuffer_id));
-			self.renderbuffer_id = 0;
-		}
-	}
-
-	fn hw_gl_create_fbo(&mut self, width: u32, height: u32) {
-		unsafe {
-			if self.fbo_id != 0 {
-				self.hw_gl_delete_fbo();
-			}
-
-			gl::GenFramebuffers(1, std::ptr::addr_of_mut!(self.fbo_id));
-			gl::BindFramebuffer(gl::FRAMEBUFFER, self.fbo_id);
-
-			gl::GenTextures(1, std::ptr::addr_of_mut!(self.texture_id));
-			gl::BindTexture(gl::TEXTURE_2D, self.texture_id);
-
-			gl::TexImage2D(
-				gl::TEXTURE_2D,
-				0,
-				gl::RGBA8 as i32,
-				width as i32,
-				height as i32,
-				0,
-				gl::RGBA,
-				gl::UNSIGNED_BYTE,
-				std::ptr::null(),
-			);
-
-			gl::GenRenderbuffers(1, std::ptr::addr_of_mut!(self.renderbuffer_id));
-			gl::BindRenderbuffer(gl::RENDERBUFFER, self.renderbuffer_id);
-
-			gl::RenderbufferStorage(
-				gl::RENDERBUFFER,
-				gl::DEPTH_COMPONENT,
-				width as i32,
-				height as i32,
-			);
-
-			gl::FramebufferTexture2D(
-				gl::FRAMEBUFFER,
-				gl::COLOR_ATTACHMENT0,
-				gl::TEXTURE_2D,
-				self.texture_id,
-				0,
-			);
-
-			gl::BindTexture(gl::TEXTURE_2D, 0);
-
-			gl::FramebufferRenderbuffer(
-				gl::FRAMEBUFFER,
-				gl::DEPTH_ATTACHMENT,
-				gl::RENDERBUFFER,
-				self.renderbuffer_id,
-			);
-
-			gl::BindRenderbuffer(gl::RENDERBUFFER, 0);
-
-			gl::Viewport(0, 0, width as i32, height as i32);
-
-			gl::BindFramebuffer(gl::FRAMEBUFFER, 0);
-
-			// Notify the frontend layer about the new FBO
-			let id = self.fbo_id;
-			self.get_frontend().set_gl_fbo(id);
-
-			// Resize the readback buffer
-			self.readback_buffer.resize((width * height) as usize, 0);
-		}
-	}
-
-	// Main loop
-	fn main_loop(&mut self) -> ! {
-		let frontend = self.get_frontend();
-
-		let av_info = frontend.get_av_info().expect("???");
-		let step_ms = (1.0 / av_info.timing.fps) * 1000.;
-		let step_duration = Duration::from_micros((step_ms * 1000.) as u64);
-
-		// Do the main loop
-		loop {
-			frontend.run_frame();
-			std::thread::sleep(step_duration);
-		}
-	}
-}
-
-impl FrontendInterface for App {
-	fn video_resize(&mut self, width: u32, height: u32) {
-		tracing::info!("Resized to {width}x{height}");
-
-		// Resize OpenGL resources if we need to.
-		if self.hw_render {
-			self.hw_gl_create_fbo(width, height);
-		}
-
-		self.rfb_server.resize(width as u16, height as u16);
-	}
-
-	fn video_update(&mut self, slice: &[u32], pitch: u32) {
-		//let framebuffer_size = self.get_frontend().get_size();
-		self.rfb_server.update_buffer(&slice, pitch, false);
-	}
-
-	fn video_update_gl(&mut self) {
-		let dimensions = self.get_frontend().get_size();
-
-		unsafe {
-			gl::BindFramebuffer(gl::FRAMEBUFFER, self.fbo_id);
-
-			// I know this sucks but it works for this case.
-			gl::ReadPixels(
-				0,
-				0,
-				dimensions.0 as i32,
-				dimensions.1 as i32,
-				gl::RGBA,
-				gl::UNSIGNED_BYTE,
-				self.readback_buffer.as_mut_ptr() as *mut std::ffi::c_void,
-			);
-
-			self.rfb_server
-				.update_buffer(&self.readback_buffer[..], dimensions.0, true);
-
-			gl::BindFramebuffer(gl::FRAMEBUFFER, 0);
-		}
-	}
-
-	fn audio_sample(&mut self, _slice: &[i16], _size: usize) {}
-
-	fn input_poll(&mut self) {
-		self.pad.reset();
-
-		// Press all buttons the VNC server marked as pressed
-		let buttons = self.rfb_server.get_buttons();
-		for i in 0..buttons.len() {
-			if buttons[i] {
-				self.pad.press_button(i as u32, None);
-			}
-		}
-	}
-
-	fn hw_gl_init(&mut self) -> HwGlInitData {
-		if self.hw_render {
-			panic!("Cannot initalize HW rendering more than once");
-		}
-
-		unsafe {
-			// Initalize EGL
-			self.hw_gl_egl_init();
-
-			// load OpenGL functions (using EGL loader. We should probably check the one extension exists)
-			gl::load_with(|s| {
-				let str = std::ffi::CString::new(s).expect("Uhh huh.");
-				std::mem::transmute(egl::GetProcAddress(str.as_ptr()))
-			});
-
-			// set OpenGL debug message callback
-			gl::Enable(gl::DEBUG_OUTPUT);
-			gl::DebugMessageCallback(Some(opengl_message_callback), std::ptr::null());
-
-			// Create the initial FBO for the core to render to
-			let dimensions = self.get_frontend().get_size();
-			self.hw_gl_create_fbo(dimensions.0, dimensions.1);
-		}
-
-		self.hw_render = true;
-
-		return unsafe {
-			HwGlInitData {
-				get_proc_address: std::mem::transmute(egl::GetProcAddress as *mut std::ffi::c_void),
-			}
-		};
-	}
-}
+use app::*;
+use rfb::RfbServerConfig;
 
 fn main() -> Result<()> {
 	// Setup a tracing subscriber
@@ -387,20 +23,32 @@ fn main() -> Result<()> {
 	tracing::subscriber::set_global_default(subscriber).unwrap();
 
 	let matches = command!()
-		.arg(arg!(--core <VALUE>).required(true))
-		// Not that it matters, but this is only really required for cores that require
-		// content to be loaded; that's most cores, but libretro does support the difference.
-		// TODO: A core will tell us if it requires content, if it's not provided we can yell and exit.
-		.arg(arg!(--rom <VALUE>).required(false))
+		.about("Headless VNC libretro frontend (with GPU rendering support)")
+		.arg(
+			arg!(--core <VALUE>)
+				.required(true)
+				.help("libretro core to load")
+				.short('c'),
+		)
+		.arg(
+			arg!(--rom <VALUE>)
+				.required(false)
+				.help("ROM to load into core")
+				.short('r'),
+		)
 		.arg(
 			arg!(--rfb_listen <ADDRESS>)
 				.required(false)
+				.help("VNC listen address")
+				.short('l')
 				.default_value("127.0.0.1"),
 		)
 		.arg(
 			arg!(--rfb_port <PORT>)
 				.value_parser(value_parser!(u16))
-				.required(true),
+				.required(true)
+				.help("VNC listen port")
+				.short('p'),
 		)
 		.get_matches();
 
@@ -419,11 +67,11 @@ fn main() -> Result<()> {
 		listen_port: *matches.get_one::<u16>("rfb_port").unwrap(),
 	};
 
-	// Initalize the app
 	let mut app = App::new(rfb_config)?;
 
 	app.load_core(core_path)?;
 
+	// TODO: Make sure to fail if a core requests content but it was never provided
 	if let Some(rom_path) = matches.get_one::<String>("rom") {
 		app.load_game(rom_path)?
 	}